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22 octobre 2010 5 22 /10 /octobre /2010 03:51

Information and Communication Technologies for Development (ICT4D) is a general term referring to the application of Information and Communication Technologies (ICTs) within the field of socioeconomic development, international development and human rights. ICT4D concerns itself with directly applyinginformation technology approaches to poverty reduction        (Dell XPS M1210 Battery)         .

ICTs can be applied either in the direct sense, wherein their use directly benefits the disadvantaged population, or in an indirect sense, wherein the ICTs assist aid organisations or non-governmental organizations or governments or businesses in order to improve general socio-economic conditions. In many impoverished regions of the world, legislative and political measures are required to facilitate or enable application of ICTs, especially with respect to monopolistic communications structures and censorship laws       (Dell Studio XPS 1340 Battery)         .

The concept of ICT4D can be interpreted as dealing with disadvantaged populations anywhere in the world, but is more typically associated with applications in developing countries. The field is becoming recognized as an interdisciplinary research area as can be noted by the growing number of conferences, workshops and publications        (Dell Studio XPS 1640 Battery)   .

Such research have been spurred on in part by the need for scientifically validated benchmarks and results, which can be used to measure the efficacy of current projects.  Many international development agencies recognize the importance of ICT4D. For example the World Bank's GICT section has a dedicated team of some 200 staff working on these issues       (Dell Vostro 1710 Battery)       .

A good example of the impact of ICTs on development are farmers getting better market price information and thus boosting their income.  Community ecenter in the Philippines developed a website to promote its local products worldwide.  Another example includes mobile telecommunications and radio broadcasting fighting political corruption in Burundi.

The dominant terminology used in this field is "ICT4D". Alternatives include ICTD and development informatics      (ASUS EEE PC900 battery) .


A telecentre in Gambia

The history of ICT4D can, roughly, be divided into three periods:

  • ICT4D 0.0: mid-1950s to late-1990s. During this period (before the creation of the term "ICT4D"), the focus was on computing / data processing for back office applications in large government and private sector organisations in developing countries   (Dell RM791 battery)          .
  • ICT4D 1.0: late-1990s to late-2000s. The combined advent of the Millennium Development Goals and mainstream usage of the Internet in industrialised countries led to a rapid rise in investment in ICT infrastructure and ICT programmes / projects in developing countries. The most typical application was thetelecentre, used to bring information on development issues such as health, education, and agricultural extension into poor communities         (Sony VGP-BPS13 battery)     .
  • More latterly, telecentres might also deliver online or partly online government services.
  • ICT4D 2.0: late-2000s onwards. There is no clear boundary between phase 1.0 and 2.0 but suggestions of moving to a new phase include the change from the telecentre to the mobile phone as the archetypal application; less concern with e-readiness and more interest in the impact of ICTs on development; and more focus on the poor as producers and innovators with ICTs (as opposed to just consumers of ICT-based information)      (Sony VGP-BPL9 battery)         .




ICT4D initiatives and projects may be designed and implemented by international institutions, private companies (e.g. Intel's Classmate), governments (e.g. e-Mexico initiative), non-governmental organizations (e.g. International Institute for Communication and Development), or virtual organizations (e.g. One Laptop per Child). The projects can typically be evaluation research, matching a tool and a problem, exploratory research, or constructive research         (Sony VGP-BPL11 battery)          .

ICT4D projects address one or more of the following issues:

  • Access and Infrastructure: providing suitable computer hardware, operating systems, software, and connectivity to the internet. These would include the affordability of software and hardware, the ability to share software (as echoed in the Free Software movement), and the ability to sustainably connect to the internet        (Sony VGP-BPL15 battery)       .
  • Capacity building and training in ICT: installing, maintaining, and developing hardware and software, digital literacy (technological literacy and informational literacy) and e-Awareness.
  • Digital content and services: e-services (e-learning, e-health, e-business/e-commerce, e-Governance/e-Government), including concerns related to local-language solutions in computing, and theOpen Access agenda     (Dell Inspiron E1505 battery)         .
  • Regulation of the ICT Sector and digital rights: Universal Access vs. monopolistic structures, Intellectual Property Rights, privacy, security, and digital identity.
  • Ethics and Social Contexts
  • Environment and Agriculture
  • Free and Open Source Software     (Dell Latitude E6400 battery)
  • Gender and ICT
  • Health and Medicine
  • Policy and Social Analyses
  • Technical Innovation for Development
  • India Development Gateway Project (Agriculture, Primary Education, Social Welfare, Rural Energy, e-Governance and Health  (HP Pavilion dv6000 Battery)        )


Bad access roads and lack of power hamper ICT4D Projects in rural areas

Projects which deploy technologies in underdeveloped areas face well-known problems concerning crime, problems of adjustment to the social context, and also possibly infrastructural problems    (Sony Vaio VGN-FZ31S battery)        .

The literacy issue is one of the factors why projects fail in rural areas; proper education and training is needed to make the user at least understand how to manipulate the application to get the information they need. Constant follow up with the community is needed to monitor if the project is being used or implemented    (Sony Vaio VGN-FZ31S battery)      .

Projects in marginalised rural areas face the most significant hurdles. Since people in marginalised rural areas are at the very bottom of the pyramid, development efforts should make the most difference in this sector. ICTs have the potential to multiply development effects   and are thus also meaningful in the rural arena.  However introducing ICTs in these areas is also most costly, as the following barriers exist     (Hp pavilion dv6000 battery)        :

  • Lack of Infrastructure: no power, no running water, bad roads
  • Lack of Health Services: diseases like HIV, TB, malaria are more common.
  • Lack of Employment: there are practically no jobs in marginalised rural areas.
  • Hunger: hungry users have problems concentrating     (Sony VGN-FW11S Battery)         .
  • Illiteracy: Text user interfaces do not work very well, innovative Human Computer Interfaces (see Human Computer Interaction) are required.
  • Lack of means to maintain the project: some projects may be left to deteriorate in time because if a component gets broken they are costly to repair and maintain.
  • Lack of support from the local government       (Sony VGP-BPS13A/B Battery)
  • Social Contexts: the potential users living in rural marginalised areas often cannot easily see the point of ICTs, because of social context and also because of the impediments of hunger, disease and illiteracy.
  • Possibility of encouraging brain-drain.
  • Corruption is one of the factors that hampers the implementation of ICT projects in rural areas     (Toshiba Satellite P10 Battery)          .
  • Training and seminars must be conducted according to a suitable time for farmers, to make sure that their daily routine is not affected.
  • Many applications are not user friendly.
  • Projects are sometimes not being needs-driven     (SONY VAIO VGN-FZ210CE Battery)        .

The World Bank runs Information for Development Program (infoDev), whose Rural ICT Toolkit analyses the costs and possible profits involved in such a venture and shows that there is more potential in developing areas than many might assume.  The potential for profit arises from two sources- resource sharing across large numbers of users (specifically, the publication talks about line sharing, but the principle is the same for, e.g. telecentres at which computing / Internet are shared) and remittances (specifically the publication talks about carriers making money from incoming calls, i.e. from urban to rural areas       (Hp Pavilion dv3-1000 battery)        .

Remittances are estimated to have a volume of upward of 250 billion USD and websites have been established to take advantage of this fact (e.g. Aryty, Philippines; Mukuru.com, Zimbabwe.

One of the main challenge in overcoming the digital divide is to widen the influence of the respective policies from those carried out by telecommunications authority, to the entire public sector         (Dell Precision M70 Battery)         .

While most of the national digital agendas are led by national telecommunications authorities, such as the FCC and NTIA, the case of Chile shows that the funds managed by the telecom authority represent less than 5 % of the total funds spent by the overall government on ICT-related policies and projects (spread out over 22 governmental departments), such as carried out the national health department, the education ministry or the finance department        (Acer Aspire One battery)         .

The funds available for ICT4D throughout the public sector are a large multiple of those spent by technology and infrastructure authorities alone. Countries and international organizations usually do not know which agency manages which kinds of ICT-funds, and do not even make an effort to track these resources. Since ICT for development is about more than providing mere access to technologies          (Toshiba Satellite L305 Battery)       ,

the logical conclusion is to coordinate the funds and projects implemented by telecommunications and technologies authorities, with those managed by health, education, finance and defense authorities. The first task consists of taking inventory of the funds available to the entire public sector. This is generally not done and not even the actors and decision makers have a coherent picture about what is done. Double efforts and lack of synergies are the common result           (Toshiba Satellite Pro M15 Battery)     .

Lessons learned

What's crucial in making any ICT4D effort successful is effective partnership between four key stakeholders:

  • Public sector (governments - from developed nations, developing nations, international bodies, and local governments)
  • Private sector (companies belonging to members of the target audience, multi-national organizations wishing to expand their markets to the 4 billion people under US$2/day, pro-poor or social companies         (Toshiba Satellite M65 battery)     )
  • Informal sector (NGOs, advocacy groups, think tanks)
  • Representation from the target audience

InfoDev have published 6 lessons from an analysis of 17 their pilot programmes (see below). These lessons are backed by a variety of examples as well as a list of recommendations       (Toshiba Satellite T4900 Battery)     :

  • Lesson 1: Involve target groups in project design and monitoring.
  • Lesson 2: When choosing the technology for a poverty intervention project, pay particular attention to infrastructure requirements, local availability, training requirements, and technical challenges. Simpler technology often produces better results            (Toshiba PA3399U-2BRS battery)     .
  • Lesson 3: Existing technologies—particularly the telephone, radio, and television—can often convey information less expensively, in local languages, and to larger numbers of people than can newer technologies. In some cases, the former can enhance the capacity of the latter        (Toshiba Satellite A200 Battery)          .
  • Lesson 4: ICT projects that reach out to rural areas might contribute more to the MDGs than projects based in urban areas.
  • Lesson 5: Financial sustainability is a challenge for ICT-for-development initiatives.
  • Lesson 6: Projects that focus on ICT training should include a job placement component        (Toshiba Satellite 1200 Battery)  .

Sustainability and scalability

A Geekcorps volunteer setting up a Wi-Fiantenna in Mali

A growing perspective in the field is also the need to build projects that are sustainable and scalable, rather than focusing on those which must be propped up by huge amounts of external funding and cannot survive for long without it. Sustaining the project's scalability is a huge challenge of ICT for development; how the target user will continue using the platform          (Toshiba NB100 Battery)        .

ICT4D is not one shot implementation but rather it is a complex process to be undertaken continuously, and the progress of each project evolves around the pervasive education for, and adaptability of, the technology

Also, many so-called "developing" countries, such as India (or other South Asian countries like Sri Lanka, Pakistan, and Bangladesh, as also nations likeMalaysia, China, Indonesia, Brazil, South Africa and many others) have proved their skills in IT (information technology)           (Toshiba Satellite M300 Battery)          .

In this context, unless these skills are tapped adequately to build on ICT4D projects, not only will a lot of potential be wasted, but a key indigenous partner in the growth of this sector would be lost. Also there would be unnecessary negative impact on the balance of payments due to imports in both hardware and software         (Dell INSPIRON 1525 battery)       .

Currently, the main two perspectives coming out of this sector either emphasize the need for external aid to build infrastructure before projects can touch viability, or the need to develop and build on local talent. Both approaches are, of course, not mutually exclusive       (Dell Latitude D830 Battery)        .


Satellite Internet access via VSAT is a common form of connectivity in developing countries ([[Ghana, Ecamic project]] pictured)

As it has grown in popularity, especially in the international development sector, ICT4D has also increasingly come under criticism. For instance, questions have been raised about whether projects that have been implemented at enormous cost are actually designed to be scalable, or whether these projects make enough of an impact to produce noticeable change          (Dell Studio 1735 Battery)       .

In Sri Lankan journalist Nalaka Gunawardene argues that thousands of pilot projects have been seeded without regard to generalisability, scalability, and sustainability, implying that these projects will always require external funding to continue running and that their impact is limited.[21] This sentiment echoes a 2003 report by the World Bank        (Dell Latitude D620 Battery)        .

Further criticism on ICT4D concerns the impact of ICTs on traditional cultures and the so-called cultural imperialism which may be spread with ICTs. For example, young males are tempted to spend their recreational time playing violent computer games. It is emphasised that local language content and software seem to be good ways to help soften the impact of ICTs in developing areas     (SONY VAIO VGN-FZ150E Battery)            .

Many fear of the potential of ICT to seriously widen the Digital Divide and the gap between people with access to information economy and those without. This issue was brought to the forefront of the international agenda and was heavily discussed in some major international political meetings such as the G8 meeting in Okinawa, Japan last July, 2000      (Sony VGN-FZ31Z Battery)   .

Anriette Esterhuysen, an advocate for ICT4D and human rights in South Africa , pointed out that some ICT4D projects often give more emphasis to how ICT can help its beneficiaries economically rather than helping them create a society where social justice and equal rights prevail. She believes that sustainable development can only be achieved if there are human rights and people can speak freely         (SONY VAIO VGN-FZ38M Battery)         .

Another point of criticism against ICT4D is that its projects are seldom environmentally friendly. Beneficiary communities are often given the responsibility to dispose of the toxic electronic scrap when an equipment breaks down beyond repair. Since transporting the equipment to a recycling facility is costly; the equipment is often disposed of improperly, thus contributing to the pollution of the environment       (SONY VAIO VGN-FZ21m Battery)       .


Graph of Internet users per 100 inhabitants between 1997 and 2007 by International Telecommunication Union

Mobile phone subscribers per 100 inhabitants growth in developed and developing world between 1997 and 2007

ICT4D projects typically try to employ low-cost, low-powered technology that can be sustainable in developing environment. The challenge is large, since it is estimated that 40 % of the world's population has less than US$ 20 per year available to spend on ICT     (SONY VAIO VGN-FZ18m Battery)          .

In Brazil, the poorest 20% of the population counts with merely US$ 9 per year to spend on ICT (US$ 0.75 per month)  . This is the economic reality of these income segments in developing countries and the magnitude of the challenge to provide one laptop per child. From Latin America it is known that the borderline between ICT as a necessity good and ICT as a luxury good is roughly around the “magical number” of US$ 10 per person per month, or US$ 120 per year        (SONY VAIO VGN-FZ11m Battery)       .

This is how much ICT people seem to strive for and this is therefore how much ICT everybody would like to have as a minimum. In light of this reality, telecentre, desktop virtualization and multiseat configurations are probably the most simple and common way to affordable computing as of today     (Dell Studio 1555 Battery)           .

ICT4D projects need to be properly monitored and implemented; the system's design and user interface should be suitable to the target users. ICT4D projects installed without proper coordination with its beneficiary community has a tendency to fall short of its main objectives. For example, the usage of ICT4D projects in the farming sector in third world countries, where a majority of the population are considered to be technologically illiterate; projects lie idle and sometimes get damaged or become obsolete         (Dell Latitude D610 Battery)            .

Furthermore, there should be a line of communication between the project coordinator and the user for immediate response to the query of, or the difficulty encountered by, the user. Addressing properly the problem will help encourage the user via interactivity and participation      (Dell Vostro 1500 Battery)      .

Notable events

World Summit on the Information Society (WSIS)

A major event for ICT4D was the twin WSIS (WSIS) - lead organisation was the International Telecommunications Union (ITU). The first part of WSIS took place in Geneva, Switzerland in December 2003 (with a large ICT4D exhibition and an ICT4D symposium co-ordinated by infoDev). The second part of WSIS took place in Tunis, Tunisia, in November 2005          (Dell Latitude D610 Battery)   .

One of its chief aims of the WSIS process was to seek solutions to help bridge the so-called "digital divide" separating rich countries from poor countries by spreading access to the Internet in the developing world.

Perspectives on the WSIS are available elsewhere on Wikipedia, and this covers links to civil society, Tunis 2005, US priorities at WSIS, media responses, Tunis conference developments, roles for business and government, digital divide issues, the digital divide and the digital dilemma,common ground, a civil society study on WSIS, and external links     (Toshiba Satellite M60 battery)     .

World Summit on the Information Society (WSIS)Stocktaking

WSIS Stocktaking is a publicly accessible database of ICT-related implementation activities, initiated during the Tunis phase of WSIS. WSIS Stocktaking Database has become an effective tool for the exchange of information on the projects in relation to the implementation of the 11 Action Lines. It is worth mentioning that many of entries reflect more than one flagship initiative and project carried out by the WSIS Stakeholders           (SONY VAIO VGN-FZ11S Battery)       .

Read more. All Stakeholders are welcomed: Governments, International Organizations, Private Sector, Civil Society, Others.

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21 octobre 2010 4 21 /10 /octobre /2010 04:10

A quiet PC is a personal computer that makes little noise. Common uses for quiet PCs include video editing, sound mixing, home servers, and home theater PCs. A typical quiet PC uses quiet cooling and storage devices and energy-efficient parts      (Dell XPS M1210 Battery)          .

Like noise, the term "quiet PC" is subjective and there is currently no standard definition for a "quiet PC". However, a general definition accepted by some is that the sound emitted by such PCs should not exceed 30 dBA when measured 1 meter away from the computer      (Dell Studio XPS 1340 Battery)          .

In addition to the average sound pressure level, the frequency spectrum and dynamics of the sound are important in determining if the sound of the computer is noticed. Sounds with a smooth frequency spectrum (lacking audible tonal peaks), and little temporal variation are less likely to be noticed. The character and amount of other sound in the environment also affects how much sound will be noticed or masked, so a computer may be quiet with relation to a particular environment or set of users      (Dell Studio XPS 1640 Battery)          .

Causes of noise

The main causes of PC noise are:

  • Mechanical friction noise generated by micro motors and fan bearings, as well as vibration noise from low quality chassis and improper assemblies.
  • Turbulence caused by obstructions in the flow of air, such as poorly designed fan grilles and heatsinks. A lack of clearance between rotating fan blades and nearby support struts and grilles will create an audible noise, similar to how a mechanical siren operates         (Dell Vostro 1710 Battery)        .
  • As the fan blades spin, they produce a vortex of air that trails off the edge of the blade. When the vortexes path crosses an object it may produce noise. Fan blades can be designed to reduce this problem by using special notched shapes.
  • Noise generated by electrical coils or transformers used in power supplies, motherboards, video cards or LCD monitors .     (ASUS EEE PC900 battery)

Noise in personal computers has been increasing with rising computing power and number of transistors on a single die (integrated circuit). More transistors of a given size use more power, which releases more heat. Faster-rotating cooling fans are one common way to remove this heat. Also, motor rotation speed for hard disc drive (HDD) and Optical disc drive (ODD) has been rising for faster data processing with technical advances in micro motors         (Dell RM791 battery)         .

Faster rotation (usually measured in RPM) causes higher bearing friction, thus more noise, given the same bearing technology.

The noise issue had received widespread attention with AMD's early Athlon CPUs and Intel's Pentium 4 Prescott core CPU known for its excessive heat and bundled fan noise running on high RPM. With the introduction of Home Theatre PCs (HTPC), the excessive heat and noise problem, that had been mostly confined to the overclocking and quiet computing communities, came to the attention of the general public      (Sony VGP-BPS13 battery)              .

The main approaches to reducing noise problems from personal computers are:

  1. Reduce heat generation by using energy efficient parts - nearly all the energy used by a computer is converted into heat.
  2. Improve cooling - by using more efficient cooling parts and lower friction, quieter bearings.
  3. Use Soundproofing to reduce the effects of remaining noise sources         (Sony VGP-BPL9 battery)           .

Common noise reduction methods

  • Replace heat sinks with more efficient models. This often entails the use of larger copper or aluminum heat sinks which may incorporate heat pipes.
  • Replace fans with passive cooling solutions where possible, such as fans on motherboards and GPUs.
  • Replace fans with low-speed, large-diameter fans with low bearing and motor noise. Larger fans can move more air per revolution than smaller fans        (Sony VGP-BPL11 battery)         .
  • Replace the constant-speed fan in the power supply with a thermostatically controlled variable speed fan that runs at less than maximum speed, and thus runs quieter most of the time.
  • Replace the power supply with a quieter model. The main considerations, from a noise-reduction point of view, in choosing a power supply are fan quality, AC/DC conversion efficiency, and how good the thermal fan speed control is at keeping the fan running slow and steady. Efficiency is important because the less heat that is produced the less work the fan has to perform (Sony VGP-BPL15 battery)          .
  • Replace hard drives with quieter models. Hard drives can also be replaced with laptop hard drives, with solid state devices likecompact flash or networked file systems like NFS. This reduces or eliminates this source of noise and reduces system power and cooling requirements.
  • Place a damping material around hard drives (or other spinning drives) such as Sorbothane   (Dell Inspiron E1505 battery)   .
  • Cover the case with sound insulation material such as rubber, foam or fiber mat, although this method has limited effectiveness. The material can (because of its weight) dampen case resonance, and can also absorb some high-frequency sound. Care must be taken to be sure the soundproofing does not interfere with airflow and cooling       (Dell Latitude E6400 battery)           .
  • In energy-hungry computers, water cooling may be necessary for quiet operation. Older water pumps sometimes can make systems noisier than air-cooled, low-power computers. However, recent advances in 12v DC pump technologies have resulted in highly reduced noise levels from many pumps. In a modern watercooling system geared towards silence rather than performance, the loudest component in the computer is often the Hard Drive or Optical disc drive when performing accesses to the media            (HP Pavilion dv6000 Battery)      .

Low-cost methods

A number of methods exist for reducing computer noise at little or no added cost.

  • Reduce CPU supply voltage ("undervolting"). Many of today's CPUs can run stably at their stock speed, or even with a slight overclock, at a reduced voltage, which reduces heat output.Underclocking can be done for the same effect, however this reduces performance and is not as effective as undervolting; all the same, underclocking may allow further undervolting         (Sony Vaio VGN-FZ31S battery)      .
  • Power consumption is approximately proportional to V2·f, that is, it varies linearly with the clock frequency and quadratically with the voltage.This means that even a small reduction in voltage can have a large effect in power consumption. Undervolting and underclocking can also be used with chipsets and GPUs.
  • Enable Cool'n'Quiet for AMD CPUs or EIST on Intel's CPUs          (Sony Vaio VGN-FZ31S battery)         .
  • Reduce fan speed. For newer computers, the speed of fans can be varied automatically, depending on how hot certain parts of the computer get. Lowering a DC fan motor's supply voltage will reduce its speed while making it quieter and lowering the amount of air the fan moves. Doing this arbitrarily could lead to components overheating; therefore, whenever performing hardware work it is advised to monitor the temperature of system components          (Hp pavilion dv6000 battery)         .
  • Fans with Molex connectors can be modified easily. With 3-pin fans, either fixed inline resistors or diodes, or commercial fan controllers, such as the Zalman Fanmate, can be used. Software like speedfan may allow fan speed control. Many newer motherboards support Pulse-width modulation (PWM) control, allowing the fan speed to be set in the BIOS or with software          (Sony VGN-FW11S Battery)          .
  • Mount fans on anti-vibration mounts.
  • Remove restrictive fan grills to allow easier airflow, or replace noisy fan grills with quieter versions.
  • Use software such as Nero DriveSpeed to reduce the speed of optical drives.
  • Isolate hard disk noise, either by using anti-vibration mounts (generally rubber or silicone grommets), or by suspending the hard disk to fully decouple it from the computer chassis by mounting it in a 5.25 inch drive bay with viscoelastic polymer mounts         (Sony VGP-BPS13A/B Battery)            .
  • Set the hard disk's AAM value to its lowest setting. This reduces the seek noise produced by the hard drive, but also reduces performance slightly.
  • Set operating system to spin down hard drives after a short time of inactivity. This may reduce a drive's life span and commonly conflicts with the OS and running programs, though it can still be useful for drives that are only used for data storage          (Toshiba Satellite P10 Battery)       .
  • Defragment the hard drives to reduce the drive heads' need to search widely for data, also improves performance. This may not be practical or even possible with some operating systems, such as Linux, UNIX or Free BSD.
  • Arrange components and cables to improve airflow. Wires hanging inside the computer can block the airflow, which can increase the temperature. They can be easily moved to the side of the case so that air can pass through more easily (SONY VAIO VGN-FZ210CE Battery)         .
  • Remove dust from inside the computer. Dust on computer parts will retain more heat. Fans draw in dust along with outside air, it can build up quickly inside the computer. Dust can be removed with a vacuum cleaner, gas duster or compressed air. Special anti-static vacuum cleaners should be used however to prevent electrostatic discharge (ESD). Ideally, this would be done often enough to prevent a significant amount of dust from ever building up. How frequently this would need to be performed would depend entirely on the environment in which the computer is used         (Hp Pavilion dv3-1000 battery)      .

Sound power and pressure measurement

Though standards do exist for measuring and reporting sound power output by such things as computer components, they are often ignored. Many manufacturers do not give sound power measurements. Some report sound pressure measurements, but those that do often do not specify how sound pressure measurements were taken. Even such basic information as measurement distance is rarely reported     (Dell Precision M70 Battery)          .

Without knowing how it was measured, it is not possible to verify these claims, and comparisons between such measurements (e.g. for product selection) are meaningless. Comparative reviews, which test several devices under the same conditions are more useful. Although even then, an average sound pressure level is only one factor in determining which components will be perceived as quieter            (Acer Aspire One battery)          .

Individual components in a quiet PC

The following are notes regarding individual components in quiet PCs.

The motherboard, CPU and video card are major energy users in a computer. Components that need less power will be easier to cool quietly. The a quiet power supply is selected to be efficient when providing enough power for the computer        (Toshiba Satellite L305 Battery)             .


Main article: Motherboards

Passively cooled northbridge chipsets help reduce noise.

A motherboard based on a chipset that uses less energy may be easier to cool quietly.

Many modern motherboard chipsets have hot northbridges (notably nForce4), which may come with active cooling, usually a small, noisy fan. Fanless heatsinks, such as the Zalman ZM-NB47J, ZM-NBF47 or the Thermalright HR-05, may be used to eliminate a noisy chipset fan          (Toshiba Satellite Pro M15 Battery)          .

Some motherboard manufacturers have got rid of these fans by incorporating large heatsinks or heatpipe coolers, however they still require good case airflow to remove heat. Also, motherboard voltage regulators often have heatsinks and may need airflow to ensure adequate cooling.

Motherboards can also produce coil noise.

Undervolting and underclocking generally require motherboard support.

Some motherboards can control the fan speed using software like speedfan. Most recent motherboards have built in PWM based fan control for one or two fans         (Toshiba Satellite M65 battery)          .


A large copper heatsink and high flow fan provide exceptional cooling for the cooler-running Pentium 4 Northwood.

The heat output of a CPU can vary according to its brand and model - to be exact, its TDP. Intel's third revision Pentium 4, using the "Prescott" core, was infamous for being one of the hottest-running CPUs on the market. By comparison, AMD's Athlon series and the new Intel Core 2 perform better at lower clock speeds, and thus produce less heat        (Toshiba Satellite T4900 Battery)         .

Modern CPUs often incorporate energy saving systems, such as Cool'n'Quiet, LongHaul, and EIST. These reduce the CPU clock speed and core voltagewhen the processor is idle, thus reducing heat. The heat produced by CPUs can be further reduced by undervolting, underclocking or both        (Toshiba PA3399U-2BRS battery)        .

Most modern mainstream and value CPUs are made with a lower TDP to reduce heat, noise, and power consumption. Most of Intel's desktop Core 2 Duo processors have 65W TDPs, and AMD has newer processors with a TDP between 35W and 65W. Some processors come in special low power versions      (Toshiba Satellite A200 Battery)       .

Modern low power CPUs

Maximum TDP:

  • Athlon 64 X2: 45W, 65W, 85W
  • Intel Core and Core 2 series: 35W, 65W, 85W
  • Intel Pentium M and Celeron M (lacks SpeedStep)
  • VIA C7: 12W-20W (Fanless)
  • transmeta processors
  • Geode (processor): 5W, 25W
  • Intel Atom: 2W, 4W, 8W
  • Loongson: 1W, 5W, 7W (Fanless)     (Toshiba Satellite 1200 Battery)

Video cards

Video cards can produce a significant amount of heat. A fast GPU may be the largest power consumer in a computer. For instance, 161 watts peak power consumption for an ATI Radeon HD 2900 XT 512. Because of space limitations, video card coolers often use small fans running at high speeds, making them noisy   (Toshiba NB100 Battery)     .

Display options for making a quiet computer include:

  • Use motherboard video output - typically motherboard video takes less power than an external video card, typically at the price of lower gaming or HD video decoding performance.
  • Select a video card that does not use a fan
    • many of the more efficient GPUs are available in fanless models
    • many older video cards used less power than more recent video cards, thus heatsinks or fans were often not required
  • Replace the GPU cooler with a larger heatsink and possibly a larger, slower fan            (Toshiba Satellite M300 Battery)
  • No video card - use a terminal, thin client, USB display or desktop sharing software if display required

Power supplies

Main article: Computer power supply

PSUs are made quieter through the use of higher efficiency (which reduces waste heat and need for airflow), quieter fans, more intelligent fan controllers (ones for which the correlation between temperature and fan speed is more complex than linear), more effective heatsinks and through designs which allow air to flow through with less resistance.

For a given power supply size, more efficient supplies, such as those certified 80 plus, generate less heat        (Dell INSPIRON 1525 battery)            .

Selecting a power supply of appropriate wattage for the computer is important for high efficiency and minimizing heat. Power supplies are typically less efficient when lightly or heavily loaded. High wattage power supplies will typically be less efficient when lightly loaded, for instance when the computer is idle or sleeping. Most desktop computers spend most of their time lightly loaded   (Dell Latitude D830 Battery)          .

For example, most desktop PCs draw less than 250 watts at full load, and 200 watts or less is more typical.

Power supplies with thermally controlled fans can be made quieter by providing a cooler and/or less obstructed source of air. For instance, the power supply is in a separate compartment in the Antec P180 to keep the air supplied to the PSU cool.

The fan in a power supply can be replaced with a quieter one, although there is a risk of electric shock when doing this, and it usually voids the warranty                     (Dell Studio 1735 Battery)          .

Fanless power supplies are available.

  • Some of them are equipped with large passive heat sinks and rely on convection or case airflow to dissipate heat. It is also imperative that such fanless power supplies be installed in a case with good ventilation.
  • There are also fanless DC to DC power supplies that operate like those in laptops, using an external power brick to supply DC power, which is then converted to appropriate voltages and regulated for use by the computer.  These power supplies usually have lower wattage ratings        (Dell Latitude D620 Battery)    .

The electrical coils in power supplies can produce noise which can become noticeable in a quiet PC.


Main article: Computer case

Antec P180, with isolated chambers for more segregated airflow.

Another example of the Antec P180, this one demonstrating the use of the Scythe Ninja, a fanless CPU cooler       (SONY VAIO VGN-FZ150E Battery)          .

Cases designed for low noise usually include reasonably quiet fans, and often come with a relatively quiet power supply. Some cases for quiet computers incorporate heatsinks to cool components passively.

Cases that provide lots of space make it easier to quiet a PC, both by allowing for airflow and by accommodating large coolers    (Sony VGN-FZ31Z Battery)            .

Case airflow

Noise optimized cases like the Antec P180 and Antec P150 often have ducting and partitioning within the case to optimize airflow and thermally isolate components. For example, the P180 has the PSU mounted in the bottom of the case in an isolated partition. This design feature allows cooler air to enter the PSU, reducing the necessary airflow and accordingly, the noise output of the fan. Apple has also employed this tactic in their G5 workstations in an effort to reduce noise         (SONY VAIO VGN-FZ38M Battery)         .

Antec's Sonata is often considered by the mainstream to be one of the quietest PC cases; however, it has since been surpassed by the P180 and other more-advanced cases. Vents and ducts may easily be added to regular cases.

More obstructive fan grills increase pressure drop and lower airflow, necessitating higher fan speeds and more noise output. They also increase the turbulence of the flow, which causes some noise of its own        (SONY VAIO VGN-FZ21m Battery)           .

Cases designed to be quiet typically have wire grills or honeycombed fan grills, which perform almost as well as wire grills; both are far superior to the old style of stamped grill.

Features that facilitate neat cable management, such as brackets and space to run cables behind motherboard tray, help increase cooling efficiency         (SONY VAIO VGN-FZ18m Battery)          .

Air filtering

Air filters can help to prevent dust from coating heatsinks and surfaces, thereby impeding heat transfer, making fans spin faster. However the filter itself can increase noise if it restricts airflow too much, or is not cleaned, requiring a larger or faster fan to handle the pressure drop behind the filter.

Regular cleaning of air intake filters will help to keep airflow minimally restricted and keep the interior clean        (SONY VAIO VGN-FZ11m Battery)           .

In some cases a fine mesh intake screen is sufficient to stop most large dust particles from entering the system. These screens should be vacuumed or washed to remove dust.

Case soundproofing

The inside of a case can be lined with dampening materials to reduce noise by:

  • attenuating the vibration of the case panels via extensional damping or constrained-layer damping.
  • reducing the amplitude of the vibration of the case panels by increasing their mass.
  • absorbing airborne noise, such as with foam          (Dell Studio 1555 Battery)           .

Cooling systems

Main article: Computer cooling

Heat sinks

Main article: Heat sink

Heat sinks that operate efficiently with little airflow are often used in quiet computers. Typically they are (relatively) large, and have larger spaces to allow freer airflow. Often heat pipes are used to help distribute heat. For instance, in 2007, the Scythe Ninja or the Thermalright Ultra-120 were frequently used as CPU heat sinks in quiet computers         (Dell Latitude D610 Battery)          .


Main article: Computer fan

A 120 mm variable speed fan.

Bearing and motor noise vary between different fan models and often between different samples of the same model.

Quiet PCs typically use larger (e.g. 120 mm) low-speed fans. Although 140 mm fans are made by some manufacturers, such as Aerocool and Yate Loon, there are very few cases or heatsinks that can use them. Fan adapters, which allow larger fans to be used in place of smaller ones, and fan brackets, like the Zalman FB123, often help when replacing small fans        (Dell Vostro 1500 Battery)  .

Quiet fan manufacturers include Nexus, EBM-Papst, Yate Loon and Scythe. In situations where the resistance to flow is very low, like in free-air conditions,Noctua fans also perform very well. Extensive comparative surveys have been posted by Silent PC Review and MadShrimps.

Fan controllers can be used to slow down fans and to precisely choose fan speed. Fan controllers can produce a fixed fan speed using an inline resistor or diode, or a variable speed using a potentiometer or Pulse Width Modulation (PWM)      (Dell Latitude D610 Battery)       .

Resistor-based fan control feeds the fan a lower voltage, while PWM fan control rapidly cycles between feeding the fan full voltage and no voltage. PWM fan control reduces rotational speed, and is the easiest and most efficient option for motherboards which have PWM fan headers. This is because PWM fans in conjunction with the motherboard chipset obtain temperature data from Digital Temperature Sensors on the CPU itself. All PWM fans are four pin, and if plugged into a conventional three pin supply will operate at full speed just like a three pin fan         (Toshiba Satellite M60 battery)            .

Fans can also be plugged into the power supply's 5 volt line instead of the 12 volt line (or between the two for a potential difference of 7 volts, although this cripples the fan's speed sensing) to run them at a reduced speed. Most fans will run at 5 volts once they are spinning, but may not start reliably at less than 7 V. Some simple fan controllers will only vary the fans' supply voltage between 8 V and 12 V to avoid this problem entirely. Some fan controllers start the fan at 12 V, then drop the voltage after a few seconds        (SONY VAIO VGN-FZ11S Battery)     .

Soft mounting fans (e.g. with rubber or silicone fan isolators) can help reduce transfer of fan vibrations to other components.

Intel has recently developed a piezoelectric fan for use in desktop PCs, which is quieter than motor fans and consumes a fraction of the power         (HP Pavilion DV7 Battery)         .


Main article: Watercooling

Watercooling is a method of heat-dissipation by transferring the heat through a conductive material which is in contact with a liquid, most often demineralised water and an additive to prevent bacterial growth and provide cosmetic effects. This heated water travels in a loop which usually contains a reservoir, radiator and pump. Recent advances in 12v DC pump technologies (for the first time specifically geared-for pc development) allow for new pumps to be both extremely powerful and extremely quiet     (Dell Vostro 1400 Battery)         .

Loops can be made up of any combination of these items and some aren't required such as the radiator or reservoir if alternatives methods are used. The radiator often uses one or more fans to air cool the radiator fins and dissipate the majority of the heat at this point.

The most common loop order is reservoir to pump, radiator then the watercooling block and back to the reservoir         (Dell RM791 battery)        .

The radiator and fan efficiency has the greatest effect on the noise level and cooling efficiency but watercooling is currently the most effective and potentially quietest methods of cooling above ambient temperatures.

There is an inherent danger in the use of water around electrical equipment and leak testing the loop is always recommended before attaching any parts to the motherboard, after all loop connections have been made. The 12v DC pump can be run using batteries or a power supply making sure no power is going to any other part of the system     (SONY VAIO VGN-FZ Battery)       .

Because of these risks and the use of water under pressure watercooling is a greater technical challenge to set up due to the number of components and case modification usually required.

Secondary storage

Hard drives

Main article: Hard drives

Silicone grommets in a computer case for mounting a hard drive to reduce vibration.

Previously, hard drives used ball bearing motors, but they got noisy when the rotational speed of the drive was increased to 5400 RPM or 7200 RPM. More recent desktop hard drives use fluid bearing motors. The first hard drive widely reputed to be quiet was the Seagate Barracuda ATA IV       (Hp 520 battery)              .

The smaller 2.5" form-factor hard drives generally vibrate less, are quieter, and use less power than the traditional 3.5" drives. On the other hand, they often have lower performance and less capacity, and cost more per gigabyte.

To minimize vibrations from a hard drive being transferred to, and amplified by, the case, hard drives can be mounted with soft rubber studs, suspended with elastics or placed on soft foam or Sorbothane           (HP Pavilion dv9000 battery)           .

Hard disk enclosures can also help reduce drive noise. Care must be taken to ensure that the drive gets adequate cooling. Hard disk temperatures can often be monitored by SMART software.

Solid-state storage

Flash memory

Solid-state drive

Solid-state drive (SSD) storage offers faster seek times, lower power consumption, no moving parts; making it theoretically more reliable and silent. There is scope for very high capacity drives; however, they are currently extremely expensive per GB and are fairly scarce      (Dell Vostro 1000 battery)           .

Compact Flash cards

A few people use Compact Flash (CF) cards for storage. Because they use IDE protocol, a simple adapter is all that is needed to connect CF cards to function as an IDE or PC Card hard disk. CF cards are also small, allowing SFF PCs to be made, produce no noise, use very little power (further reducing heat output in the AC/DC conversion in the PSU), and an insignificant amount of heat. However, they are very expensive per GB and are only available in small capacities     (Dell XPS M2010 battery)         .

There are also issues regarding the maximum number of writes to each sector; often specified as 100,000 write cycles. However, there are industrial grade cards which specify a higher number of erase cycles, and different file systems, or technologies such as Enhanced Write Filter can reduce the writes to the card. Also, CF cards will fail gradually, so it will be easy to notice before any significant amount of data are lost, unlike the possible immediate failure of HDDs           (Dell XPS M1530 battery)           .

Due to their small capacities they are easy to back up entirely, and often have 10 year or even lifetime warranties.

Windows minimization projects such as Winimize (Windows 98, less than 20MB) and Linux projects such as Puppy Linux mean that running an OS in small capacity, cheap compact flash card is possible. Because they have many OS components removed, they are less prone to viruses and other malware         (Dell Studio 1737 battery)              .

The sustained transfer rate of current CF cards is a maximum of around 25 MB/s, compared to an average of around 70 MB/s for modern hard drives. However, the speed of flash memory is increasing at a faster rate than that of hard drives, and they have minimal seek times compared to hard drives, which increases the speed of loading many small files, and makes the PC seem more responsive as most operations performed by the OS include small files          (Dell Inspiron 300M Battery)          .

Due to the fast seek times CF cards also don't show the effects of file system fragmentation like hard drives do.

Newer CF cards support faster transfer protocols like DMA. It is possible to use a Compact Flash card for storing only information that isn't changed very often, such as music, videos and binary executables, while storing the small configuration files and other frequently modified data on a small hard drive or i-RAM       (Dell Studio 1735 Battery)           .

USB flash drives

Main article: USB flash drives

Where a motherboard supports booting from USB drives, they can be used in a similar fashion to CF cards to run the OS. With some Linux distributions, it is not much harder than using a CF card. As they both use flash memory, they have the same advantages and disadvantages, however speed is limited by the USB bus      (Dell Studio 1555 Battery)          .

Gigabyte i-RAM

The i-RAM is a solid-state disk which has four DIMM slots to allow regular PC RAM to be used like a disk. It is much faster than a hard disk, does not have the write cycle limitations of flash memory, however it requires power continuously in order to maintain its contents (from standby power or a battery when the system is off), uses more power than many laptop hard drives, has maximum capacity of 4 GiB, and is expensive          (Dell Latitude E6400 battery)            .

Problems and solutions

All forms of affordable solid-state storage offer relatively small capacity. They can be used as main storage for tasks which do not use large amounts of data or large programs, such as web browsing or word processing. Larger files and programs can be stored on a secondary hard drive which is only accessed when needed. Keeping the OS, often accessed files, and smaller programs on a solid-state drive means that the hard drives can be powered down much of the time           (Sony Vaio VGN-FZ61B battery)     .

Network-attached storage, or NAS, is another alternative, allowing loud hard drives to be stored remotely.

Small USB drives or CF cards can be used to make the process of network booting easier also.

Optical drives

Optical drives can be slowed down by software to quiet them, such as Nero DriveSpeed, or emulated by virtual drive programs such as Daemon Tools to eliminate their noise entirely. Notebook optical drives can be used, which tend to be quieter, however this may be because they tend to run slower (typically 24x CD speed, 8x DVD speed). Some DVD drives have a feature, commonly calledRiplock, which reduces drive noise by slowing the drive during video playback         (Acer Aspire One battery)             .

External components


Main article: Laptops

Laptop computers typically do not have power supply fans or video card fans, and they use smaller hard drives. They also use many lower power components. However, laptop CPU coolers are usually smaller, so may be noisier than their desktop counterparts. Limited space, limited access and proprietary components make silencing laptops more difficult          (HP Pavilion DV4 Battery)          .

A few laptops do not use cooling fans, for instance the Dell Latitude X1, Panasonic Toughbook W5 and T5, Fujitsu Lifebook P7120. Also, some netbooks, such as the Dell Mini 9, 10 and 12 do not have fans. The Mini 9 used SSD rather than a hard disk. The OLPC XO-1 has no internal moving parts .


Main article: Computer display

CRT monitors can produce coil noise, as can the external power supply for an LCD monitor or the voltage converter for the monitor's backlight                   (SONY VAIO VGN-FZ460E Battery)         .

LCD monitors tend to produce the least noise (whine) from when at full brightness. Reducing brightness using the video card does not introduce whine, but may reduce color accuracy.An LCD monitor with an external power supply tucked out of the way will produce less noticeable noise than one with the power supply built into the screen housing         (Dell Vostro A90 Battery)            .


Main article: Computer printer

Dot matrix and daisy wheel printers are often noisy, and soundproofed boxes or cabinets can be used to reduce the noise. Another solution is to locate the printer away from the immediate work area or in another room, especially if it can be controlled through a local area network        (Dell Vostro A860 Battery)            .

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20 octobre 2010 3 20 /10 /octobre /2010 04:21

Green computing or green IT, refers to environmentally sustainable computing or IT. In the article Harnessing Green IT: Principles and Practices, San Murugesan defines the field of green computing as "the study and practice of designing, manufacturing, using, and disposing of computers, servers, and associated subsystems—such as monitors, printers, storage devices, and networking and communications systems—efficiently and effectively with minimal or no impact on the environment      (Dell XPS M1210 Battery)      ."

The goals of green computing are similar to green chemistry; reduce the use of hazardous materials, maximize energy efficiency during the product's lifetime, and promote the recyclability or biodegradability of defunct products and factory waste. Research continues into key areas such as making the use of computers as energy-efficient as possible, and designing algorithms and systems for efficiency-related computer technologies         (Dell Studio XPS 1340 Battery)          .


In 1992, the U.S. Environmental Protection Agency launched Energy Star, a voluntary labeling program which is designed to promote and recognize energy-efficiency in monitors, climate control equipment, and other technologies. This resulted in the widespread adoption of sleep mode among consumer electronics       (Dell Studio XPS 1640 Battery)          .

The term "green computing" was probably coined shortly after the Energy Star program began; there are several USENET posts dating back to 1992 which use the term in this manner.Concurrently, the Swedish organization TCO Development launched the TCO Certification program to promote low magnetic and electrical emissions from CRT-based computer displays; this program was later expanded to include criteria on energy consumption, ergonomics, and the use of hazardous materials in construction      (Dell Vostro 1710 Battery)             .

Regulations and industry initiatives

The Organisation for Economic Co-operation and Development (OECD) has published a survey of over 90 government and industry initiatives on "Green ICTs", i.e. information and communication technologies, the environment and climate change. The report concludes that initiatives tend to concentrate on the greening ICTs themselves rather than on their actual implementation to tackle global warming and environmental degradation      (ASUS EEE PC900 battery) .

In general, only 20% of initiatives have measurable targets, with government programs tending to include targets more frequently than business associations.


Many governmental agencies have continued to implement standards and regulations that encourage green computing. The Energy Star program was revised in October 2006 to include stricter efficiency requirements for computer equipment, along with a tiered ranking system for approved products      (Dell RM791 battery)           .

Some efforts place responsibility on the manufacturer to dispose of the equipment themselves after it is no longer needed; this is called the extended producer responsibility model. The European Union's directives 2002/95/EC (Restriction of Hazardous Substances Directive), on the reduction of hazardous substances, and 2002/96/EC (Waste Electrical and Electronic Equipment Directive) on waste electrical and electronic equipment required the substitution of heavy metals and flame retardants like Polybrominated biphenyl and Polybrominated diphenyl ethers in all electronic equipment put on the market starting on July 1, 2006          (Sony VGP-BPS13 battery)           .

The directives placed responsibility on manufacturers for the gathering and recycling of old equipment.

There are currently 26 US States that have established state-wide recycling programs for obsolete computers and consumer electronics equipment. The statutes either impose an "advance recovery fee" for each unit sold at retail, or require the manufacturers to reclaim the equipment at disposal    (Sony VGP-BPL9 battery).


Climate Savers Computing Initiative (CSCI) is an effort to reduce the electric power consumption of PCs in active and inactive states.[9] The CSCI provides a catalog of green products from its member organizations, and information for reducing PC power consumption. It was started on 2007-06-12. The name stems from the World Wildlife Fund's Climate Savers program, which was launched in 1999.[10] The WWF is also a member of the Computing Initiative (Sony VGP-BPL11 battery)   .

The Green Electronics Council offers the Electronic Product Environmental Assessment Tool (EPEAT) to assist in the purchase of "greener" computing systems. The Council evaluates computing equipment on 51 criteria - 23 required and 28 optional - that measure a product's efficiency and sustainability attributes. Products are rated Gold, Silver or Bronze depending on how many optional criteria they meet      (Sony VGP-BPL15 battery)        .

On 2007-01-24, President George W. Bush issued Executive Order 13423, which requires all United States Federal agencies to use EPEAT when purchasing computer systems.

The Green Grid is a global consortium dedicated to advancing energy efficiency in data centers and business computing ecosystems. It was founded in February 2007 by several key companies in the industry – AMD, APC, Dell, HP, IBM, Intel, Microsoft, Rackable Systems, SprayCool, Sun Microsystems and VMware         (Dell Inspiron E1505 battery)       .

The Green Grid has since grown to hundreds of members, including end users and government organizations, all focused on improving data center efficiency.

The Green500 list rates supercomputers by energy efficiency (megaflops/watt, encouraging a focus on efficiency rather than absolute performance        (Dell Latitude E6400 battery)            .

Green Comm Challenge is an organization that promotes the development of energy conservation technology and practices in the field of Information and Communications Technology (ICT). Green Comm Challenge achieved worldwide notoriety in 2007, when it enlisted as one of the challengers in the 33rd edition of the America's Cup, an effort meant to show how researchers, technologists and entrepreneurs from around the world can be brought together by an exciting vision: building the ultimate renewable energy machine, a competitive America’s Cup boat          (HP Pavilion dv6000 Battery)         .

Approaches to green computing

In the article Harnessing Green IT: Principles and Practices, San Murugesan defines the field of green computing as "the study and practice of designing, manufacturing, using, and disposing of computers, servers, and associated subsystems—such as monitors, printers, storage devices, and networking and communications systems—efficiently and effectively with minimal or no impact on the environment      (Sony Vaio VGN-FZ31S battery) ."

Murugesan lays out four paths along which he believes the environmental effects of computing should be addressed: Green use, green disposal, green design, and green manufacturing.

Modern IT systems rely upon a complicated mix of people, networks and hardware; as such, a green computing initiative must cover all of these areas as well         (Sony Vaio VGN-FZ31S battery)        .

A solution may also need to address end user satisfaction, management restructuring, regulatory compliance, and return on investment (ROI). There are also considerable fiscal motivations for companies to take control of their own power consumption; "of the power management tools available, one of the most powerful may still be simple, plain, common sense     (Hp pavilion dv6000 battery)             ."

Product longevity

Gartner maintains that the PC manufacturing process accounts for 70 % of the natural resources used in the life cycle of a PC. Therefore, the biggest contribution to green computing usually is to prolong the equipment's lifetime. Another report from Gartner recommends to "Look for product longevity, including upgradability and modularity        (Sony VGN-FW11S Battery)    ."

For instance, manufacturing a new PC makes a far bigger ecological footprint than manufacturing a new RAM module to upgrade an existing one, a common upgrade that saves the user having to purchase a new computer.

Software and deployment optimization

Algorithmic efficiency

Main article: Algorithmic efficiency

The efficiency of algorithms has an impact on the amount of computer resources required for any given computing function and there are many efficiency trade-offs in writing programs        (Sony VGP-BPS13B/B Battery)    .

As computers have become more numerous and the cost of hardware has declined relative to the cost of energy, the energy efficiency and environmental impact of computing systems and programs has received increased attention. A study by Alex Wissner-Gross, a physicist at Harvard, estimated that the average Google search released 7 grams of carbon dioxide (CO?).  However, Google disputes this figure, arguing instead that a typical search produces only 0.2 grams of CO?     (Sony VGP-BPS13A/B Battery)         .

Resource allocation

Main article: Resource allocation

Algorithms can also be used to route data to data centers where electricity is less expensive. Researchers from MIT, Carnegie Mellon University, and Akamai have tested an energy allocation algorithm that successfully routes traffic to the location with the cheapest energy costs       (Toshiba Satellite P10 Battery)              .

The researchers project up to a 40 percent savings on energy costs if their proposed algorithm were to be deployed. Strictly speaking, this approach does not actually reduce the amount of energy being used; it only reduces the cost to the company using it. However, a similar strategy could be used to direct traffic to rely on energy that is produced in a more environmentally friendly or efficient way       (SONY VAIO VGN-FZ210CE Battery)       .

A similar approach has also been used to cut energy usage by routing traffic away from data centers experiencing warm weather; this allows computers to be shut down to avoid using air conditioning.

Larger server centers are sometimes located where energy and land are inexpensive and readily available. Local availability of renewable energy, climate that allows outside air to be used for cooling, or locating them where the heat they produce may be used for other purposes could be factors in green siting decisions          (Hp Pavilion dv3-1000 battery)            .


Main article: Platform virtualization

See also: Comparison of platform virtual machines

Computer virtualization refers to the abstraction of computer resources, such as the process of running two or more logical computer systems on one set of physical hardware. The concept originated with the IBM mainframe operating systems of the 1960s, but was commercialized for x86-compatible computers only in the 1990s      (Dell Precision M70 Battery)         .

With virtualization, a system administrator could combine several physical systems into virtual machines on one single, powerful system, thereby unplugging the original hardware and reducing power and cooling consumption. Virtualization can assist in distributing work so that servers are either busy, or put in a low power sleep state. Several commercial companies and open-source projects now offer software packages to enable a transition to virtual computing             (Acer Aspire One battery)         .

Intel Corporation and AMD have also built proprietary virtualization enhancements to the x86 instruction set into each of their CPU product lines, in order to facilitate virtualized computing.

Terminal servers

Main article: Terminal server

Terminal servers have also been used in green computing. When using the system, users at a terminal connect to a central server; all of the actual computing is done on the server, but the end user experiences the operating system on the terminal       (Toshiba Satellite L305 Battery)          .

These can be combined with thin clients, which use up to 1/8 the amount of energy of a normal workstation, resulting in a decrease of energy costs and consumption.  There has been an increase in using terminal services with thin clients to create virtual labs. Examples of terminal server software include Terminal Services for Windows and the Linux Terminal Server Project (LTSP) for the Linux operating system         (Toshiba Satellite Pro M15 Battery)             .

Power management

Main article: Power management

The Advanced Configuration and Power Interface (ACPI), an open industry standard, allows an operating system to directly control the power-saving aspects of its underlying hardware          (Toshiba Satellite M65 battery)           .

This allows a system to automatically turn off components such as monitors and hard drives after set periods of inactivity. In addition, a system may hibernate, where most components (including the CPU and the system RAM) are turned off. ACPI is a successor to an earlier Intel-Microsoft standard called Advanced Power Management, which allows a computer's BIOS to control power management functions                (Toshiba Satellite T4900 Battery)          .

Some programs allow the user to manually adjust the voltages supplied to the CPU, which reduces both the amount of heat produced and electricity consumed. This process is called undervolting. Some CPUs can automatically undervolt the processor depending on the workload; this technology is called "SpeedStep" on Intel processors, "PowerNow!"/"Cool'n'Quiet" on AMD chips, LongHaul on VIA CPUs, and LongRun with Transmeta processors         (Toshiba PA3399U-2BRS battery)        .

Operating system support

The dominant desktop operating system, Microsoft Windows, has included limited PC power management features since Windows 95. These initially provided for stand-by (suspend-to-RAM) and a monitor low power state. Further iterations of Windows added hibernate (suspend-to-disk) and support for the ACPI standard        (Toshiba Satellite A200 Battery)      .

Windows 2000 was the first NT based operating system to include power management. This required major changes to the underlying operating system architecture and a new hardware driver model. Windows 2000 also introduced Group Policy, a technology which allowed administrators to centrally configure most Windows features         (Toshiba Satellite 1200 Battery)     .

However, power management was not one of those features. This is probably because the power management settings design relied upon a connected set of per-user and per-machine binary registry values, effectively leaving it up to each user to configure their own power management settings         (Toshiba NB100 Battery)          .

This approach, which is not compatible with Windows Group Policy, was repeated in Windows XP. The reasons for this design decision by Microsoft are not known, and it has resulted in heavy criticism  Microsoft significantly improved this in Windows Vista  by redesigning the power management system to allow basic configuration by Group Policy        (Toshiba Satellite M300 Battery)      .

The support offered is limited to a single per-computer policy. The most recent release, Windows 7 retains these limitations but does include refinements for more efficient user of operating system timers, processor power management,  and display panel brightness. The most significant change in Windows 7 is in the user experience. The prominence of the default High Performance power plan has been reduced with the aim of encouraging users to save power      (Dell INSPIRON 1525 battery)          .

There is a significant market in third-party PC power management software offering features beyond those present in the Windows operating system. Most products offer Active Directory integration and per-user/per-machine settings with the more advanced offering multiple power plans, scheduled power plans, anti-insomnia features and enterprise power usage reporting      (Toshiba NB100 Battery)  .

Power supply

Desktop computer power supplies (PSUs) are generally 70–75% efficient,dissipating the remaining energy as heat. An industry initiative called 80 PLUS certifies PSUs that are at least 80% efficient; typically these models are drop-in replacements for older, less efficient PSUs of the same form factor.  As of July 20, 2007, all new Energy Star 4.0-certified desktop PSUs must be at least 80% efficient       (Dell Latitude D830 Battery) .


Smaller form factor (e.g. 2.5 inch) hard disk drives often consume less power per gigabyte than physically larger drives. Unlike hard disk drives, solid-state drives store data in flash memory or DRAM. With no moving parts, power consumption may be reduced somewhat for low capacity flash based devices      (Dell Studio 1735 Battery)  .

In a recent case study, Fusion-io, manufacturers of the world's fastest Solid State Storage devices, managed to reduce the carbon footprint and operating costs of MySpace data centers by 80% while increasing performance speeds beyond that which had been attainable via multiple hard disk drives in Raid 0. In response, MySpace was able to permanently retire several of their servers, including all their heavy-load servers, further reducing their carbon footprint       (Dell Latitude D620 Battery)     .

As hard drive prices have fallen, storage farms have tended to increase in capacity to make more data available online. This includes archival and backup data that would formerly have been saved on tape or other offline storage. The increase in online storage has increased power consumption. Reducing the power consumed by large storage arrays, while still providing the benefits of online storage, is a subject of ongoing research   (SONY VAIO VGN-FZ150E Battery)     .

Video card

A fast GPU may be the largest power consumer in a computer.

Energy efficient display options include:

No video card - use a shared terminal, shared thin client, or desktop sharing software if display required.

Use motherboard video output - typically low 3D performance and low power     (Sony VGN-FZ31Z Battery)      .

Select a GPU based on low idle power, average wattage or performance per watt.


CRT monitors typically use more power than LCD monitors. They also contain significant amounts of lead. LCD monitors typically use a cold-cathode fluorescent bulb to provide light for the display. Some newer displays use an array of light-emitting diodes (LEDs) in place of the fluorescent bulb, which reduces the amount of electricity used by the display      (SONY VAIO VGN-FZ38M Battery)  .

Fluorescent back-lights also contain mercury, whereas LED back-lights do not.

Materials recycling

Main articles: Electronic waste and computer recycling

Recycling computing equipment can keep harmful materials such as lead, mercury, and hexavalent chromium out of landfills, and can also replace equipment that otherwise would need to be manufactured, saving further energy and emissions    (SONY VAIO VGN-FZ21m Battery)       .

Computer systems that have outlived their particular function can be re-purposed, or donated to various charities and non-profit organizations.  However, many charities have recently imposed minimum system requirements for donated equipment.Additionally, parts from outdated systems may be salvaged and recycled through certain retail outlets and municipal or private recycling centers. Computing supplies, such as printer cartridges, paper, and batteries may be recycled as well                 (SONY VAIO VGN-FZ18m Battery)       .

A drawback to many of these schemes is that computers gathered through recycling drives are often shipped to developing countries where environmental standards are less strict than in North America and Europe.  The Silicon Valley Toxics Coalition estimates that 80% of the post-consumer e-waste collected for recycling is shipped abroad to countries such as China and Pakistan       (SONY VAIO VGN-FZ11m Battery)             .

The recycling of old computers raises an important privacy issue. The old storage devices still hold private information, such as emails, passwords and credit card numbers, which can be recovered simply by someone using software that is available freely on the Internet. Deletion of a file does not actually remove the file from the hard drive        (SONY VAIO VGN-FZ31z Battery)        .

Before recycling a computer, users should remove the hard drive, or hard drives if there is more than one, and physically destroy it or store it somewhere safe. There are some authorized hardware recycling companies to whom the computer may be given for recycling, and they typically sign a non-disclosure agreement     (Sony VGN-FW11S Battery)         .


Main article: Telecommuting

Teleconferencing and telepresence technologies are often implemented in green computing initiatives. The advantages are many; increased worker satisfaction, reduction of greenhouse gas emissions related to travel, and increased profit margins as a result of lower overhead costs for office space, heat, lighting, etc     (Dell Studio 1555 Battery,Dell Latitude D610 Battery)              .

The savings are significant; the average annual energy consumption for U.S. office buildings is over 23 kilowatt hours per square foot, with heat, air conditioning and lighting accounting for 70% of all energy consumed. Other related initiatives, such as hotelling, reduce the square footage per employee as workers reserve space only when they need it     (Dell Vostro 1500 Battery)         .

Many types of jobs, such as sales, consulting, and field service, integrate well with this technique.

Voice over IP (VoIP) reduces the telephony wiring infrastructure by sharing the existing Ethernet copper. VoIP and phone extension mobility also made hot desking more practical       (Toshiba Satellite M60 battery)      .

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A monitor or display (sometimes called a visual display unit) is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel, while older monitors use a cathodic ray tube about as deep as the screen size         (Dell XPS M1210 Battery)             .

Originally computer monitors were used for data processing and television receivers for entertainment; increasingly computers are being used both for data processing and entertainment. Displays exclusively for data use tend to have an aspect ratio of 4:3; those used also (or solely) for entertainment are usually 16:9 widescreen, Sometimes a compromise is used, e.g. 16:10      (Dell Studio XPS 1340 Battery)          .

Screen size

Main articles: Viewable image size and Computer display standard

For any rectangular section on a round tube, the diagonal measurement is also the diameter of the tube

The area of displays with identical diagonal measurements can vary substantially      (Dell Studio XPS 1640 Battery)

The size of an approximately rectangular display is usually given as the distance between two opposite screen corners, that is, the diagonal of the rectangle. One problem with this method is that it does not take into account the display aspect ratio, so that for example a 16:9 21 in (53 cm) widescreen display is far less high, and has less area, than a 21 in (53 cm) 4:3 screen. The 4:3 screen has dimensions of 16.8 × 12.6 in (43 × 32 cm) and area 211 sq in (1,360 cm2), while the widescreen is 18.3 × 10.3 in (46 × 26 cm), 188 sq in (1,210 cm2)       (Dell Vostro 1710 Battery)           .

For many purposes the height of the display is the main parameter; a 16:9 display needs a diagonal 22% larger than a 4:3 display for the same height.

This method of measurement is inherited from the method used for the first generation of CRT television, when picture tubes with circular faces were in common use. Being circular, only their diameter was needed to describe their size         (ASUS EEE PC900 battery) .

Since these circular tubes were used to display rectangular images, the diagonal measurement of the rectangle was equivalent to the diameter of the tube's face. This method continued even when cathode ray tubes were manufactured as rounded rectangles; it had the advantage of being a single number specifying the size, and was not confusing when the aspect ratio was universally 4:3       (Dell RM791 battery)             .

A problematic practice was the use of the size of a monitor's imaging element, rather than the size of its viewable image, when describing its size in publicity and advertising materials. On CRT displays a substantial portion of the CRT's screen is concealed behind the case's bezel or shroud in order to hide areas outside the monitor's "safe area" due to overscan. These practices were seen as deceptive, and widespread consumer objection and lawsuits eventually forced most manufacturers to instead measure viewable size          (Sony VGP-BPS13 battery)           .

Performance measurements

The performance of a monitor is measured by the following parameters:

Luminance is measured in candelas per square meter (cd/m2 also called a Nit).

Viewable image size is measured diagonally. For CRTs, the viewable size is typically 1 in (25 mm) smaller than the tube itself         (sony vgp-bpl9 battery)            .

Aspect ratios is the ratio of the horizontal length to the vertical length. 4:3 is the standard aspect ratio, for example, so that a screen with a width of 1024 pixels will have a height of 768 pixels. If a widescreen display has an aspect ratio of 16:9, a display that is 1024 pixels wide will have a height of 576 pixels       (Sony VGP-BPL11 battery)          .

Display resolution is the number of distinct pixels in each dimension that can be displayed. Maximum resolution is limited by dot pitch.

Dot pitch is the distance between subpixels of the same color in millimeters. In general, the smaller the dot pitch, the sharper the picture will appear            (Sony VGP-BPL15 battery)      .

Refresh rate is the number of times in a second that a display is illuminated. Maximum refresh rate is limited by response time.

Response time is the time a pixel in a monitor takes to go from active (black) to inactive (white) and back to active (black) again, measured in milliseconds. Lower numbers mean faster transitions and therefore fewer visible image artifacts.

Contrast ratio is the ratio of the luminosity of the brightest color (white) to that of the darkest color (black) that the monitor is capable of producing          (Dell Inspiron E1505 battery )        .

Power consumption is measured in watts.

Viewing angle is the maximum angle at which images on the monitor can be viewed, without excessive degradation to the image. It is measured in degrees horizontally and vertically        (Dell Latitude E6400 battery)      .




High dynamic range (up to around 15,000:1), excellent color, wide gamut and low black level.

Can display natively in almost any resolution and refresh rate      (HP Pavilion dv6000 Battery)

No input lag

Sub-millisecond response times

Near zero color, saturation, contrast or brightness distortion. Excellent viewing angle.

Usually much cheaper than LCD or Plasma screens.

Allows the use of light guns/pens       (Hp Pavilion dv3-1000 battery)


Large size and weight, especially for bigger screens (a 20-inch unit weighs about 50 lb (23 kg))

High power consumption

Generates a considerable amount of heat when running

Geometric distortion caused by variable beam travel distances        (Dell Precision M70 Battery)

Can suffer screen burn-in

Produces noticeable flicker at low refresh rates

Normally only produced in 4:3 aspect ratio

Hazardous to repair/service

Effective vertical resolution limited to 1024 scan lines        (Acer Aspire One battery)         .

Color displays cannot be made in sizes smaller than 7 inches (5 inches for monochrome). Maximum size is 21 inches (for computer monitors; televisions run up to 40 inches).



Very compact and light      (Toshiba Satellite L305 Battery)

Low power consumption

No geometric distortion

Little or no flicker depending on backlight technology

Not affected by screen burn-in

No high voltage or other hazards present during repair/service               (Toshiba Satellite Pro M15 Battery)

More reliable than CRTs

Can be made in almost any size or shape

No theoretical resolution limit


Limited viewing angle, causing color, saturation, contrast and brightness to vary, even within the intended viewing angle, by variations in posture         (Toshiba Satellite M65 battery)           .

Bleeding and uneven backlighting in some monitors, causing brightness distortion, especially toward the edges.

Slow response times, which cause smearing and ghosting artifacts. Modern LCDs have response times of 8 ms or less.

Only one native resolution. Displaying resolutions either requires a video scaler, lowering perceptual quality, or display at 1:1 pixel mapping, in which images will be physically too large or won't fill the whole screen     (Toshiba Satellite T4900 Battery)        .

Fixed bit depth, many cheaper LCDs are only able to display 262,000 colors. 8-bit S-IPS panels can display 16 million colors and have significantly better black level, but are expensive and have slower response time

Input lag

Dead pixels may occur either during manufacturing or through use        (Toshiba PA3399U-2BRS battery)           .

In a constant on situation, thermalization may occur, which is when only part of the screen has overheated and therefore looks discolored compared to the rest of the screen.

Not all LCD displays are designed to allow easy replacement of the backlight

Cannot be used with light guns/pens          (Toshiba Satellite A200 Battery)


Main article: Plasma display


High contrast ratios (10,000:1 or greater,) excellent color, wide gamut and low black level.

High speed response.

Near zero color, saturation, contrast or brightness distortion. Excellent viewing angle.

No geometric distortion         (Toshiba Satellite 1200 Battery)      .

Softer and less blocky-looking picture than LCDs

Highly scalable, with less weight gain per increase in size (from less than 30 in (760 mm) wide to the world's largest at 150 in (3,800 mm)).


Large pixel pitch, meaning either low resolution or a large screen      (Toshiba NB100 Battery)           .

Color plasma displays cannot be made in sizes under 32 inches

Noticeable flicker when viewed at close range

Heavy weight

Glass screen can induce glare and reflections

High operating temperature and power consumption      (Toshiba Satellite M300 Battery)

Only has one native resolution. Displaying other resolutions requires a video scaler, which degrades image quality at lower resolutions.

Fixed bit depth

Can suffer image burn-in. This was a severe problem on early plasma displays, but much less on newer ones

Cannot be used with light guns/pens           (Dell INSPIRON 1525 battery)

Dead pixels are possible during manufacturing


Phosphor burn-in

Phosphor burn-in is localized aging of the phosphor layer of a CRT screen where it has displayed a static image for long periods of time. This results in a faint permanent image on the screen, even when turned off. In severe cases, it can even be possible to read some of the text, though this only occurs where the displayed text remained the same for years       (SONY VAIO VGN-FZ280E Battery)        .

Burn-in is most commonly seen in the following applications:

Point-of-service applications

Arcade games

Security monitors             (SONY VAIO VGN-FZ410 Battery)

Screen savers were developed as a means to avoid burn-in, which was a widespread problem on IBM Personal Computer monochrome monitors in the 1980s. Monochrome displays are generally more vulnerable to burn-in because the phosphor is directly exposed to the electron beam while in color displays, the shadow mask provides some protection. Although still found on newer computers, screen savers are not necessary on LCD monitors                  (SONY VAIO VGN-FZ160 Battery)          .

Phosphor burn-in can be "fixed" by running a CRT with the brightness at 100% for several hours, but this merely hides the damage by burning all the phosphor evenly. CRT rebuilders can repair monochrome displays by cutting the front of the picture tube off, scraping out the damaged phosphor, replacing it, and resealing the tube. Color displays cannot be repaired        (SONY VAIO VGN-FZ38M Battery)          .

Plasma burn-in

Burn-in re-emerged as an issue with early plasma displays, which are more vulnerable to this than CRTs. Screen savers with moving images may be used with these to minimize localized burn. Periodic change of the color scheme in use also helps       (SONY VAIO VGN-FZ21m Battery)         .


Glare is a problem caused by the relationship between lighting and screen or by using monitors in bright sunlight. Matte finish LCDs and flat screen CRTs are less prone to reflected glare than conventional curved CRTs or glossy LCDs, and aperture grille CRTs, which are curved on one axis only and are less prone to it than other CRTs curved on both axes       (SONY VAIO VGN-FZ18m Battery)        .

If the problem persists despite moving the monitor or adjusting lighting, a filter using a mesh of very fine black wires may be placed on the screen to reduce glare and improve contrast. These filters were popular in the late 1980s. They do also reduce light output.

A filter above will only work against reflective glare; direct glare (such as sunlight) will completely wash out most monitors' internal lighting, and can only be dealt with by use of a hood or transreflective LCD         (SONY VAIO VGN-FZ11m Battery)        .

Color misregistration

With exceptions of correctly aligned video projectors and stacked LEDs, most display technologies, especially LCD, have an inherent misregistration of the color channels, that is, the centers of the red, green, and blue dots do not line up perfectly. Sub-pixel rendering depends on this misalignment; technologies making use of this include the Apple II from 1976 , and more recently Microsoft (ClearType, 1998) and XFree86 (X Rendering Extension)    (SONY VAIO VGN-FZ11z Battery)     .

Incomplete spectrum

RGB displays produce most of the visible color spectrum, but not all. This can be a problem where good color matching to non-RGB images is needed. This issue is common to all monitor technologies with three color channels         (SONY VAIO VGN-FZ11l Battery) .

Display interfaces

Computer terminals

Main article: Computer terminal

Early CRT-based VDUs (Visual Display Units) such as the DEC VT05 without graphics capabilities gained the label glass teletypes, because of the functional similarity to their electromechanical predecessors        (SONY VAIO VGN-FZ31z Battery)       .

Some historic computers had no screen display, using a teletype, modified electric typewriter, or printer instead.

Composite signal

Early home computers such as the Apple II and the Commodore 64 used a composite signal output to drive a TV or color composite monitor (a TV with no tuner). This resulted in degraded resolution due to compromises in the broadcast TV standards used. This method is still used with video game consoles. The Commodore monitor had S-Video input to improve resolution, but this was not common on televisions until the event of HDTV            (Sony VGN-FW11S Battery)      .

Digital displays

Early digital monitors are sometimes known as TTLs because the voltages on the red, green, and blue inputs are compatible with TTL logic chips. Later digital monitors support LVDS, or TMDS protocols           (Sony VGP-BPS13B/B Battery)     .

TTL monitors

IBM PC with green monochrome display.

Monitors used with the MDA, Hercules, CGA, and EGA graphics adapters used in early IBM PC's (Personal Computer) and clones were controlled via TTL logic. Such monitors can usually be identified by a male DB-9 connector used on the video cable      (Toshiba Satellite P10 Battery)          .

The disadvantage of TTL monitors was the limited number of colors available due to the low number of digital bits used for video signaling            .

Modern monochrome monitors use the same 15-pin SVGA connector as standard color monitors. They are capable of displaying 32-bit grayscale at 1024x768 resolution, making them able to interface with modern computers             (SONY VAIO VGN-FZ210CE Battery)            .

TTL Monochrome monitors only made use of five out of the nine pins. One pin was used as a ground, and two pins were used for horizontal/vertical synchronization. The electron gun was controlled by two separate digital signals, a video bit, and an intensity bit to control the brightness of the drawn pixels. Only four shades were possible; black, dim, medium or bright       (Hp pavilion dv6000 battery) .

CGA monitors used four digital signals to control the three electron guns used in color CRTs, in a signaling method known as RGBI, or Red Green and Blue, plus Intensity. Each of the three RGB colors can be switched on or off independently. The intensity bit increases the brightness of all guns that are switched on, or if no colors are switched on the intensity bit will switch on all guns at a very low brightness to produce a dark grey         (Sony VGN-FW11S Battery_)      .

A CGA monitor is only capable of rendering 16 colors. The CGA monitor was not exclusively used by PC based hardware. The Commodore 128 could also utilize CGA monitors. Many CGA monitors were capable of displaying composite video via a separate jack.

EGA monitors used six digital signals to control the three electron guns in a signaling method known as RrGgBb. Unlike CGA, each gun is allocated its own intensity bit. This allowed each of the three primary colors to have four different states (off, soft, medium, and bright) resulting in 64 colors           (Dell Studio 1555 Battery)         .

Although not supported in the original IBM specification, many vendors of clone graphics adapters have implemented backwards monitor compatibility and auto detection. For example, EGA cards produced by Paradise could operate as an MDA, or CGA adapter if a monochrome or CGA monitor was used in place of an EGA monitor. Many CGA cards were also capable of operating as MDA or Hercules card if a monochrome monitor was used              (Dell Vostro 1720 Battery)      .

Single color screens

Green and amber phosphors were used on most monochrome displays in the 1970s and 1980s. White was uncommon because it was more expensive to manufacture, although Apple used it on the Lisa and early Macintoshes        (Dell Vostro 1500 Battery)          .

Modern technology

Analog monitors

Most modern computer displays can show the various colors of the RGB color space by changing red, green, and blue analog video signals in continuously variable intensities. These are almost exclusively progressive scan. Although televisions used an interlaced picture, this was too flickery for computer use. In the late 1980s and early 1990s, some VGA-compatible video cards in PCs used interlacing to achieve higher resolution, but the event of SVGA quickly put an end to them        (Dell Latitude D830 Battery)    .

While many early plasma and liquid crystal displays have exclusively analog connections, all signals in such monitors pass through a completely digital section prior to display.

While many similar connectors (13W3, BNC, etc…) were used on other platforms, the IBM PC and compatible systems standardized on the VGA connector in 1987      (Dell Latitude D620 Battery)           .

CRTs remained the standard for computer monitors through the 1990s. The first standalone LCD displays appeared in the early 2000s and over the next few years, they gradually displaced CRTs for most applications. First-generation LCD monitors were only produced in 4:3 aspect ratios, but current models are generally 16:9. The older 4:3 monitors have been largely relegated to point-of-service and some other applications where widescreen is not required           (SONY VAIO VGN-FZ150E Battery)              .

Digital and analog combination

The first popular external digital monitor connectors, such as DVI-I and the various breakout connectors based on it, included both analog signals compatible with VGA and digital signals compatible with new flat-screen displays in the same connector. Older 4:3 LCD monitors had only VGA inputs, but the newer 16:9 models have added DVI         (Dell Studio 1735 Battery)         .

Digital monitors

Monitors are being made which have only a digital video interface. Some digital display standards, such as HDMI and DisplayPort, also specify integrated audio and data connections. Many of these standards enforce DRM, a system intended to deter copying of entertainment content           (Dell Inspiron 300M Battery)                     .

Configuration and usage

Multiple monitors

Main article: Multi-monitor

More than one monitor can be attached to the same device. Each display can operate in two basic configurations             (Dell Studio 1737 battery)            :

The simpler of the two is mirroring (sometimes cloning,) in which at least two displays are showing the same image. It is commonly used for presentations. Hardware with only one video output can be tricked into doing this with an external splitter device, commonly built into many video projectors as a pass through connection      (Dell XPS M1530 battery)       .

The more sophisticated of the two, extension allows each monitor to display a different image, so as to form a contiguous area of arbitrary shape. This requires software support and extra hardware, and may be locked out on "low end" products by crippleware.

Primitive software is incapable of recognizing multiple displays, so spanning must be used, in which case a very large virtual display is created, and then pieces are split into multiple video outputs for separate monitors          (Dell XPS M2010 battery)             .

Hardware with only one video output can be made to do this with an expensive external splitter device, this is most often used for very large composite displays made from many smaller monitors placed edge to edge         (Dell Vostro 1000 battery)           .

Multiple video sources

Multiple devices can be connected to the same monitor using a video switch. In the case of computers, this usually takes the form of a "Keyboard Video Mouse switch" (KVM) switch, which is designed to switch all of the user interface devices for a workstation between different computers at once        (HP Pavilion dv9000 battery)            .

Virtual displays

Main article: Virtual desktop

Screenshot of workspaces layed out by Compiz

Much software and video hardware supports the ability to create additional, virtual pieces of desktop, commonly known as workspaces. Spaces is Apple's implementation of virtual displays       (Hp 520 battery)          .

Additional features

Power saving

Most modern monitors will switch to a power-saving mode if no video-input signal is received. This allows modern operating systems to turn off a monitor after a specified period of inactivity. This also extends the monitor's service life          (SONY VGP-BPS13 Battery)   .

Some monitors will also switch themselves off after a time period on standby.

Most modern laptops provide a method of screen dimming after periods of inactivity or when the battery is in use. This extends battery life and reduces wear       (SONY VAIO VGN-FZ Battery)           .

Integrated accessories

Many monitors have other accessories (or connections for them) integrated. This places standard ports within easy reach and eliminates the need for another separate hub, camera, microphone, or set of speakers         (Dell RM791 battery)          .

Glossy screen

Main article: Glossy display

Some displays, especially newer LCD monitors, replace the traditional anti-glare matte finish with a glossy one. This increases saturation and sharpness but reflections from lights and windows are very visible      (Toshiba Portege R200 Battery) .

Directional screen

Narrow viewing angle screens are used in some security conscious applications.

Autopolyscopic screen

Main article: Autostereoscopy

A directional screen which generates 3D images without headgear        (Toshiba Satellite M60 battery)        .

Touch screen

These monitors use touching of the screen as an input method. Items can be selected or moved with a finger, and finger gestures may be used to convey commands. The screen will need frequent cleaning due to image degradation from fingerprints.

Tablet screens         (Dell Vostro 1400 Battery)

Main article: Graphics tablet/screen hybrid

A combination of a monitor with a graphics tablet. Such devices are typically unresponsive to touch without the use of one or more special tools' pressure. Newer models however are now able to detect touch from any pressure and often have the ability to detect tilt and rotation as well.

Touch and tablet screens are used on LCD displays as a substitute for the light pen, which can only work on CRTs    (HP Pavilion DV7 Battery)          .

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In computing, a keyboard is typewriter keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. After punch cards and paper tape, interaction via teletype-style keyboards became the main input device for computers         (Dell XPS M1210 Battery)           .

Despite the development of alternative input devices, such as the mouse (computing mouse), touch sensitive screens, pen devices, character recognition, voice recognition, and improvements in computer speed and memory size, the keyboard remains the most commonly used and most versatile device used for direct (human) input into computers        (Dell Studio XPS 1340 Battery)      .

A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or computer commands          (Dell Studio XPS 1640 Battery)      .

In normal usage, the keyboard is used to type text and numbers into a word processor, text editor or other program. In a modern computer, the interpretation of key presses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all key presses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with special gaming features, which can expedite frequently used keystroke combinations  (Dell Vostro 1710 Battery)         .

A keyboard is also used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete combination, which brings up a task window or shuts down the machine. It is the only way to enter commands on a command-line interface.



Standard "full-travel" alphanumeric keyboards have keys that are on three-quarter inch centers (0.750 inches, 19.05 mm), and have a key travel of at least 0.150 inches (3.81 mm)        (ASUS EEE PC900 battery) .

Desktop computer keyboards, such as the 101-key US traditional keyboards or the 104-key Windows keyboards, include alphabetic characters, punctuation symbols, numbers and a variety of function keys. The internationally-common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y). Also the 'enter' key is usually shaped differently.  Computer keyboards are similar to electric-typewriter keyboards but contain additional keys       (Dell RM791 battery)     .


Keyboards on laptops and notebook computers usually have a shorter travel distance for the keystroke and a reduced set of keys. They may not have a numerical keypad, and the function keys may be placed in locations that differ from their placement on a standard, full-sized keyboard       (Sony VGP-BPS13 battery)       .

The keyboards on laptops have a shorter travel distance and (usually) a reduced set of keys.


Smaller keyboards have been introduced for laptops, PDAs, smartphones, or users who have a limited workspace. The size of a standard keyboard is dictated by the practical consideration that the keys must be large enough to be easily pressed by fingers. To reduce the size of the keyboard, the numeric keyboard to the right of the alphabetic keyboard can be removed, or the size of the keys can be reduced, which makes it harder to enter text        (sony vgp-bpl9 battery)        .

Another way to reduce the size of the keyboard is to reduce the number of keys and use chording keyer, i.e. pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text. Another way to reduce the size of a keyboard is to use smaller buttons and pack them closer together          (Sony VGP-BPL11 battery)        .

Such keyboards, often called a "thumbboard" (thumbing) are used in some personal digital assistants such as the Palm Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.


Numeric keyboards contain only numbers, mathematical symbols for addition, subtraction, multiplication, and division, a decimal point, and several function keys. They are often used to facilitate data entry with smaller keyboards that do not have a numeric keypad, commonly those of laptop computers. These keys are collectively known as a numeric pad, numeric keys, or a numeric keypad, and it can consist of the following types of keys     (Sony VGP-BPL15 battery)          :

arithmetic operators such as +, -, *, /

numeric digits 0–9

cursor arrow keys

navigation keys such as Home, End, PgUp, PgDown, etc.

Num Lock button, used to enable or disable the numeric pad

enter key         (Dell Inspiron E1505 battery )

Non-standard or special-use types


While other keyboards generally associate one action with each key, chorded keyboards associate actions with combinations of key presses. Since there are many combinations available, chorded keyboards can effectively produce more actions on a board with fewer keys. Court reporters' stenotype machines use chorded keyboards to enable them to enter text much faster by typing a syllable with each stroke instead of one letter at a time          (Dell Latitude E6400 battery)       .

The fastest typists (as of 2007) use a stenograph, a kind of chorded keyboard used by most court reporters and closed-caption reporters. Some chorded keyboards are also made for use in situations where fewer keys are preferable, such as on devices that can be used with only one hand, and on small mobile devices that don't have room for larger keyboards. Chorded keyboards are less desirable in many cases because it usually takes practice and memorization of the combinations to become proficient      (HP Pavilion dv6000 Battery)              .


Software keyboards or On-Screen Keyboards often take the form of computer programs that display an image of a keyboard on the screen. Another input device such as a mouse or a touchscreen can be used to operate each virtual key to enter text. Software keyboards have become very popular in touchscreen enabled cell phones, due to the additional cost and space requirements of other types of hardware keyboards. Microsoft Windows, Mac OS X, and some varieties of Linux include on-screen keyboards that can be controlled with the mouse       (Hp Pavilion dv3-1000 battery)             .


Further information: Flexible electronics

A foldable keyboard.

Foldable (also called flexible) keyboards are made of soft plastic or silicone which can be rolled or folded on itself for travel.[2] When in use, these keyboards can conform to uneven surfaces, and are more resistant to liquids than standard keyboards. These can also be connected to portable devices and smartphones. Some models can be fully immersed in water, making them popular in hospitals and laboratories, as they can be disinfected           (Dell Precision M70 Battery)            .


Projection keyboards project an image of keys, usually with a laser, onto a flat surface. The device then uses a camera or infrared sensor to "watch" where the user's fingers move, and will count a key as being pressed when it "sees" the user's finger touch the projected image. Projection keyboards can simulate a full size keyboard from a very small projector. Because the "keys' are simply projected images, they cannot be felt when pressed        (Acer Aspire One battery)          .

Users of projected keyboards often experience increased discomfort in their fingertips because of the lack of "give" when typing. A flat, non-reflective surface is also required for the keys to be projected onto. Most projection keyboards are made for use with PDAs due to their small form factor.

Optical keyboard technology

Also known as photo-optical keyboard, light responsive keyboard, Photo-electric keyboard and optical key actuation detection technology      (Toshiba Satellite L305 Battery)           .

An optical keyboard technology utilizes light emitting devices and photo sensors to optically detect actuated keys. Most commonly the emitters and sensors are located in the perimeter, mounted on a small PCB. The light is directed from side to side of the keyboard interior and it can only be blocked by the actuated keys. Most optical keyboards require at least 2 beams (most commonly vertical beam and horizontal beam) to determine the actuated key           (Toshiba Satellite Pro M15 Battery)           .

Some optical keyboards use a special key structure that blocks the light in a certain pattern, allowing only one beam per row of keys (most commonly horizontal beam).

Further information: Keyboard technology



Main article: Keyboard layout

The 104-key PC US English QWERTY keyboard layout evolved from the standard typewriter keyboard, with extra keys for computing       (Toshiba Satellite M65 battery)         .

The Dvorak Simplified Keyboard layout arranges keys so that frequently used keys are easiest to press, which reduces muscle fatigue when typing common English.

There are a number of different arrangements of alphabetic, numeric, and punctuation symbols on keys. These different keyboard layouts arise mainly because different people need easy access to different symbols, either because they are inputting text in different languages, or because they need a specialized layout for mathematics, accounting, computer programming, or other purposes      (Toshiba Satellite T4900 Battery)          .

Most of the more common keyboard layouts (QWERTY-based and similar) were designed in the era of the mechanical typewriters, so their ergonomics had to be slightly compromised in order to tackle some of the mechanical limitations of the typewriter.

As the letter-keys were attached to levers that needed to move freely, inventor Christopher Sholes developed the QWERTY layout to reduce the likelihood of jamming          (Toshiba PA3399U-2BRS battery)          .

With the advent of computers, lever jams are no longer an issue, but nevertheless, QWERTY layouts were adopted for electronic keyboards because they were widely used. Alternative layouts such as the Dvorak Simplified Keyboard are not in widespread use.

The QWERTZ layout is widely used in Germany and much of Central Europe. The main difference between it and QWERTY is that Y and Z are swapped, and most special characters such as brackets are replaced by diacritical characters      (Toshiba Satellite A200 Battery)          .

Another situation takes place with “national” layouts. Keyboards designed for typing in Spanish have some characters shifted, to release the space for Ñ ñ; similarly, those for French and other European languages may have a special key for the character Ç ç . The AZERTY layout is used in France, Belgium and some neighbouring countries. It differs from the QWERTY layout in that the A and Q are swapped, the Z and W are swapped, and the M is moved from the right of N to the right of L (where colon/semicolon is on a US keyboard        (Toshiba Satellite 1200 Battery)         .

The digits 0 to 9 are on the same keys, but to be typed the shift key must be pressed. The unshifted positions are used for accented characters.

Keyboards in many parts of Asia may have special keys to switch between the Latin character set and a completely different typing system. In Japan, keyboards often can be switched between Japanese and the Latin alphabet, and the character ¥ (the Yen currency) is used instead of "\" . In the Arab world, keyboards can often be switched between Arabic and Latin characters      (Toshiba NB100 Battery)            .

In bilingual regions of Canada and in the French-speaking province of Québec, keyboards can often be switched between an English and a French-language keyboard; while both keyboards share the same QWERTY alphabetic layout, the French-language keyboard enables the user to type accented vowels such as "é" or "à" with a single keystroke. Using keyboards for other languages leads to a conflict: the image on the key does not correspond to the character         (Toshiba Satellite M300 Battery)        .

In such cases, each new language may require an additional label on the keys, because the standard keyboard layouts do not share even similar characters of different languages (see the example in the figure above).

Key types


A Hebrew keyboard lets the user type in both Hebrew and the Latin alphabet.

A Greek keyboard lets the user type in both Greek and the Latin alphabet(Macbook Pro)      (Dell INSPIRON 1525 battery)        .

Alphabetical, numeric, and punctuation keys are used in the same fashion as a typewriter keyboard to enter their respective symbol into a word processing program, text editor, data spreadsheet, or other program. Many of these keys will produce different symbols when modifier keys or shift keys are pressed. The alphabetic characters become uppercase when the shift key or Caps Lock key is depressed         (SONY VAIO VGN-FZ280E Battery)          .

The numeric characters become symbols or punctuation marks when the shift key is depressed. The alphabetical, numeric, and punctuation keys can also have other functions when they are pressed at the same time as some modifier keys.

The Space bar is a horizontal bar in the lowermost row, which is significantly wider than other keys. Like the alphanumeric characters, it is also descended from the mechanical typewriter         (SONY VAIO VGN-FZ410 Battery)        .

Its main purpose is to enter the space between words during typing. It is large enough so that a thumb from either hand can use it easily. Depending on the operating system, when the space bar is used with a modifier key such as the control key, it may have functions such as resizing or closing the current window, half-spacing, or backspacing. In computer games and other applications the key has myriad uses in addition to its normal purpose in typing, such as jumping and adding marks to check boxes       (SONY VAIO VGN-FZ160 Battery)      .

In certain programs for playback of digital video, the space bar is used for pausing and resuming the playback.


Modifier keys are special keys that modify the normal action of another key, when the two are pressed in combination. For example, <Alt> + <F4> in Microsoft Windows will close the program in an active window. In contrast, pressing just <F4> will probably do nothing, unless assigned a specific function in a particular program. By themselves, modifier keys usually do nothing       (SONY VAIO VGN-FZ38M Battery)           .

The Ctrl and Alt keys are important modifier keys.

The most widely-used modifier keys include the Control key, Shift key and the Alt key. The AltGr key is used to access additional symbols for keys that have three symbols printed on them. On the Macintosh and Apple keyboards, the modifier keys are the Option key and Command key, respectively. On MIT computer keyboards, the Meta key is used as a modifier and for Windows keyboards, there is a Windows key. Compact keyboard layouts often use a Fn key. "Dead keys" allow placement of a diacritic mark, such as an accent, on the following letter (e.g., the Compose key)           (SONY VAIO VGN-FZ21m Battery)          .

A Space-cadet keyboard has many modifier keys.

The Enter/Return key typically causes a command line, window form or dialog box to operate its default function, which is typically to finish an "entry" and begin the desired process. In word processing applications, pressing the enter key ends a paragraph and starts a new one       (SONY VAIO VGN-FZ18m Battery)           .

Navigation and typing mode

Navigation keys include a variety of keys which move the cursor to different positions on the screen. Arrow keys are programmed to move the cursor in a specified direction; page scroll keys, such as the 'Page Up and Page Down keys', scroll the page up and down. The Home key is used to return the cursor to the beginning of the line where the cursor is located; the End key puts the cursor at the end of the line. The Tab key advances the cursor to the next tab stop       (SONY VAIO VGN-FZ11m Battery)          .

The Insert key is mainly used to switch between overtype mode, in which the cursor overwrites any text that is present on and after its current location, and insert mode, where the cursor inserts a character at its current position, forcing all characters past it one position further. The Delete key discards the character ahead of the cursor's position, moving all following characters one position "back" towards the freed place         (SONY VAIO VGN-FZ11z Battery)         .

On many notebook computer keyboards the key labeled Delete (sometimes Delete and Backspace are printed on the same key) serves the same purpose as a Backspace key. The Backspace key deletes the preceding character.

Lock keys lock part of a keyboard, depending on the settings selected. The lock keys are scattered around the keyboard. Most styles of keyboards have three LEDs indicating which locks are enabled, in the upper right corner above the numpad. The lock keys include Scroll lock, Num lock (which allows the use of the numeric keypad), and Caps lock          (SONY VAIO VGN-FZ11l Battery)           .

System commands

The SysRq / Print screen commands often share the same key. SysRq was used in earlier computers as a "panic" button to recover from crashes. The Print screen command used to capture the entire screen and send it to the printer, but in the present it usually puts a screenshot in the clipboard          (SONY VAIO VGN-FZ31z Battery)           .

The Break key/Pause key no longer has a well-defined purpose. Its origins go back to teletype users, who wanted a key that would temporarily interrupt the communications line. The Break key can be used by software in several different ways, such as to switch between multiple login sessions, to terminate a program, or to interrupt a modem connection     (Sony VGN-FW11S Battery)          .

In programming, especially old DOS-style BASIC, Pascal and C, Break is used (in conjunction with Ctrl) to stop program execution. In addition to this, Linux and variants, as well as many DOS programs, treat this combination the same as Ctrl+C. On modern keyboards, the break key is usually labeled Pause/Break. In most Windows environments, the key combination Windows key+Pause brings up the system properties            (Sony VGP-BPS13B/B Battery)         .

The Escape key (often abbreviated Esc) is used to initiate an escape sequence. As most computer users no longer are concerned with the details of controlling their computer's peripherals, the task for which the escape sequences were originally designed, the escape key was appropriated by application programmers, most often to mean Stop. This use continues today in Microsoft Windows's use of escape as a shortcut in dialog boxes for No, Quit, Exit, Cancel, or Abort                (Toshiba Satellite P10 Battery)              .

A common application today of the Esc key is as a shortcut key for the Stop button in many web browsers. On machines running Microsoft Windows, prior to the implementation of the Windows key on keyboards, the typical practice for invoking the "start" button was to hold down the control key and press escape. This process still works in Windows 2000, XP, Windows Vista and Windows 7          (SONY VAIO VGN-FZ210CE Battery)          .

The Menu key or Application key is a key found on Windows-oriented computer keyboards. It is used to launch a context menu with the keyboard rather than with the usual right mouse button. The key's symbol is a small icon depicting a cursor hovering above a menu. This key was created at the same time as the Windows key. This key is normally used when the right mouse button is not present on the mouse          (Dell Studio 1555 Battery)           .

Some Windows public terminals do not have a Menu key on their keyboard to prevent users from right-clicking (however, in many windows applications, a similar functionality can be invoked with the Shift+F10 keyboard shortcut).


Multimedia buttons on some keyboards give quick access to the Internet or control the volume of the speakers.

Many, but not all, computer keyboards have a numeric keypad to the right of the alphabetic keyboard which contains numbers, basic mathematical symbols (e.g., addition, subtraction, etc.), and a few function keys        (Dell Vostro 1720 Battery)          .

On Japanese/Korean keyboards, there may be Language input keys. Some keyboards have power management keys (e.g., Power key, Sleep key and Wake key); Internet keys to access a web browser or E-mail; and/or multimedia keys, such as volume controls .

Multiple Layouts

It possible to install multiple keyboard layout and switch among them in computer with the help of either operating system or application program. Microsoft Windows[3], Ubuntu[4], Linux[5], Mac[6] provide support to add keyboard layouts and choose from them      (Dell Vostro 1500 Battery)          .

Layout changing software

Depending on operating systems, various application programs are available to create, add and switch among keyboard layouts. For example, Ukelele for Mac, The Microsoft Keyboard Layout Creator[7] and open source Avro Keyboard for Windows. All programs give facility to customize the keyboard layout as desired. Many other similar softwares[8] are available, some of which are language specific         (Dell Latitude D830 Battery)        .


Keyboards and keypads may be illuminated from inside, especially on equipment for mobile use. Illumination facilitates the use of the keyboard or keypad in dark environments. Some gaming keyboards have lighted keys, to make it easier for gamers to find command keys while playing in a dark room. Some computers may have small LED lights in a few important function keys, to remind users that the function is activated (see photo)       (Dell Latitude D620 Battery)         .

Keys with integrated LED indicator lights


Key switches

In the first electronic keyboards in the early 1970s, the key switches were individual switches inserted into holes in metal frames. These keyboards cost from 80–120 US dollars and were used in mainframe data terminals      (SONY VAIO VGN-FZ150E Battery)    .

The most popular switch types were reed switches (contacts enclosed in a vacuum in a glass capsule, affected by a magnet mounted on the switch plunger – from Clare-Pendar in Post Falls Idaho, which became part of General Instrument, which used reedswitch capsules made by C.P. Clare Co. in Illinois; and Key Tronic Corporation of Spokane, Washington), Hall-effect switches (using a Hall-effect semiconductor where a current is generated by a passing magnet – from Microswitch in Illinois, which became part of Honeywell), and inductive core switches (again, activated by a magnet – from Cortron, which was part of ITW/Illinois Tool Works   (Dell Studio 1735 Battery)         )

. These switches were rated to last for 100 million cycles and had 0.187-inch (4.75 mm) key travel, compared to 0.110 inch (2.79 mm) today.

In the mid 1970's, lower-cost direct-contact key switches were introduced, but their life in switch cycles was much shorter (rated ten million cycles) because they were open to the environment. This became more acceptable, however, for use in computer terminals at the time, which began to see increasingly shorter model lifespans as they advanced          (Dell Inspiron 300M Battery)         .

In 1978, Key Tronic Corporation introduced keyboards with capacitive-based switches, one of the first keyboard technologies to not use self-contained switches. There was simply a sponge pad with a conductive-coated Mylar plastic sheet on the switch plunger, and two half-moon trace patterns on the printed circuit board below. As the key was depressed, the capacitance between the plunger pad and the patterns on the PCB below changed, which was detected by IC's/Integrated Circuits         (Dell Studio 1737 battery)          .

These keyboards were claimed to have the same reliability as the other "solid-state switch" keyboards such as inductive and Hall-Effect, but competitive with direct-contact keyboards. Prices of $60 for keyboards were achieved and Key Tronic rapidly became the largest independent keyboard manufacturer        (Dell XPS M1530 battery)        .

Meanwhile, IBM made their own keyboards, using their own patented technology: Keys on older IBM keyboards were made with a "buckling spring" mechanism, in which a coil spring under the key buckles under pressure from the user's finger, pressing a rubber dome, whose inside is coated with conductive graphite, which connects two leads below, completing a circuit. This produces a clicking sound, and gives physical feedback for the typist indicating that the key has been depressed      (Dell XPS M2010 battery)  .

The first electronic keyboards had a typewriter key travel distance of 0.187 inches (4.75 mm), keytops were a half-inch (12.7 mm) high, and keyboards were about two inches (5 cm) thick. Over time, less key travel was accepted in the market, finally landing on 0.110 inches (2.79 mm). Coincident with this, Key Tronic was the first company to introduce a keyboard which was only about one inch thick. And now keyboards measure only about a half-inch thick         (Dell Vostro 1000 battery)            .

Keytops are an important element of keyboards. In the beginning, keyboard keytops had a "dish shape" on top, like typewriters before them. Keyboard key legends must be extremely durable over tens of millions of depressions, since they are subjected to extreme mechanical wear from fingers and fingernails, and subject to hand oils and creams, so engraving and filling key legends with paint, as was done previously for individual switches, was never acceptable        (HP Pavilion dv9000 battery)        .

So, for the first electronic keyboards, the key names/legends were produced by two-shot (or double-shot, or two-color) molding, where either the key shell or the inside of the key with the key legend was molded first, and then the other color molded second. But, to save cost, other methods were explored, such as sublimation printing and laser engraving, both methods which could be used to print a whole keyboard at the same time        (Hp 520 battery)           .

Initially, sublimation printing, where a special ink is printed onto the keycap surface and the application of heat causes the ink molecules to penetrate and commingle with the plastic modules, had a problem because finger oils caused the molecules to disperse, but then a necessarily very hard clear coating was applied to prevent this. Coincident with sublimation printing, which was first used in high volume by IBM on their keyboards, was the introduction by IBM of single-curved-dish keycaps to facilitate quality printing of key legends by having a consistently-curved surface instead of a dish. But one problem with sublimation or laser printing was that the processes took too long and only dark legends could be printed on light-colored keys           (SONY VGP-BPS13 Battery)         .

On another note, IBM was unique in using separate shells, or "keycaps", on keytop bases. This might have made their manufacturing of different keyboard layouts more flexible, but the reason for doing this was that the plastic material that needed to be used for sublimation printing was different than standard ABS keytop plastic material.

Three final mechanical technologies brought keyboards to where they are today, driving the cost well under $10     (SONY VAIO VGN-FZ Battery)            :

"Monoblock" keyboard designs were developed where individual switch housings were eliminated and a one-piece "monoblock" housing used instead. This was possible because of molding techniques that could provide very tight tolerances for the switch-plunger holes and guides across the width of the keyboard so that the key plunger-to-housing clearances were not too tight or too loose, either of which could cause the keys to bind     (Dell RM791 battery)           .

The use of contact-switch membrane sheets under the monoblock. This technology came from flat-panel switch membranes, where the switch contacts are printed inside of a top and bottom layer, with a spacer layer in between, so that when pressure is applied to the area above, a direct electrical contact is made. The membrane layers can be printed by very-high volume, low-cost "reel-to-reel" printing machines, with each keyboard membrane cut and punched out afterwards        (Toshiba Portege R200 Battery) .

The use of pad-printed keytops (called "Tampo printed" at the time because Tampo was the most popular equipment manufacturer). Initially sublimation ink was used (see above), but very durable clear-coats are now printed over the key legends to protect them. These coatings are also used to reduce glare, and in many cases have an anti-microbial content added for user protection       (Toshiba Satellite M60 battery)                .

Plastic materials played a very important part in the development and progress of electronic keyboards. Until "monoblocks" came along, GE's "self-lubricating" Delrin was the only plastic material for keyboard switch plungers that could withstand the beating over tens of millions of cycles of lifetime use. Greasing or oiling switch plungers was undesirable because it would attract dirt over time which would eventually affect the feel and even bind the key switches (although keyboard manufacturers would sometimes sneak this into their keyboards, especially if they could not control the tolerances of the key plungers and housings well enough to have a smooth key depression feel or prevent binding)         (Dell Vostro 1400 Battery)       .

But Delrin was only available in black and white, and was not suitable for keytops (too soft), so keytops use ABS plastic. However, as plastic molding advanced in maintaining tight tolerances, and as key travel length reduced from 0.187-inch to 0.110-inch (4.75 mm to 2.79 mm), single-part keytop/plungers could be made of ABS, with the keyboard monolocks also made of ABS        (Toshiba Satellite Pro M50 Battery)        .

Control processor

Computer keyboards include control circuitry to convert key presses into key codes that the computer's electronics can understand. The key switches are connected via the printed circuit board in an electrical X-Y matrix where a voltage is provided sequentially to the Y lines and, when a key is depressed, detected sequentially by scanning the X lines         (Dell Vostro 1510 Battery)         .

The first computer keyboards were for mainframe computer data terminals and used discrete electronic parts. The first keyboard microprocessor was introduced in 1972 by General Instruments, but keyboards have been using the single-chip 8048 microcontroller variant since it became available in 1978. The keyboard switch matrix is wired to its inputs, it converts the keystrokes to key codes, and, for a detached keyboard, sends the codes down a serial cable (the keyboard cord) to the main processor on the computer motherboard         (Dell Latitude XT2 Tablet PC Battery)         .

This serial keyboard cable communication is only bi-directional to the extent that the computer's electronics controls the illumination of the "caps lock", "num lock" and "scroll lock" lights.

One test for whether the computer has crashed is pressing the "caps lock" key. The keyboard sends the key code to the keyboard driver running in the main computer; if the main computer is operating, it commands the light to turn on. All the other indicator lights work in a similar way. The keyboard driver also tracks the shift, alt and control state of the keyboard        (Dell Vostro A90 Battery)             .

Some lower-quality keyboards have multiple or false key entries due to inadequate electrical designs. These are caused by inadequate keyswitch "debouncing" or inadequate keyswitch matrix layout that don't allow multiple keys to be depressed at the same time, both circumstances which are explained below         ( HP Pavilion DV7 Battery)         :

When pressing a keyboard key, the key contacts "bounce" against each other several times for several milliseconds before they settle into firm contact (although this was not true with early "solid-state" keyswitch keyboards that used Hall-effect, inductive, or capacitive keyswitch technologies). When released, they bounce some more until they revert to the uncontacted state. If the computer were watching for each pulse, it would see many keystrokes for what the user thought was just one      (Toshiba Satellite Pro M10 Battery)        .

To resolve this problem, the processor in a keyboard (or computer) "debounces" the keystrokes, by aggregating them across time to produce one "confirmed" keystroke that (usually) corresponds to what is typically a solid contact.

Some low-quality keyboards also suffer problems with rollover (that is, when multiple keys pressed at the same time, or when keys are pressed so fast that multiple keys are down within the same milliseconds)           (Dell Inspiron 300M Battery)        .

Early "solid-state" keyswitch keyboards did not have this problem because the keyswitches are electrically isolated from each other, and early "direct-contact" keyswitch keyboards avoided this problem by having isolation diodes for every keyswitch. So, these early keyboards had "n-key" rollover, which means any number of keys can be depressed and the keyboard will still recognize the next key depressed        (Toshiba NB100 Battery )      .

But when three keys are pressed (electrically closed) at the same time in a "direct contact" keyswitch matrix that doesn't have isolation diodes (diode are not practical with current membrane-switch based keyboards), the keyboard electronics can see a fourth "phantom" key which is the intersection (shorting out) of the X and Y lines of the three keys. Some types of keyboard circuitry will register a maximum number of keys at one time, such as "three-key" rollover maximum, also called "phantom key blocking" or "phantom key lockout", meaning that it will only register three keys and ignore all others until one of the three keys is lifted     (Toshiba Satellite M65 battery)           .

This is of course undesirable, especially for fast typing (hitting new keys before the fingers can release previous keys, and undesirable for games (designed for multiple key presses).

As direct-contact membrane keyboards became popular, the available rollover of keys was optimized by analyzing the most common key sequences and placing these keys so that they do not potentially produce phantom keys in the electrical key matrix (for example, simply placing three or four keys that might be depressed simultaneously on the same X or same Y line, so that a phantom key intersection/short cannot happen), so that blocking a third key usually isn't a problem         (Sony Vaio VGN-FZ61B battery)         .

But lower-quality keyboard designs and unknowledgeable engineers may not know these tricks, and it can still be a problem in games due to wildly different and/or configurable key/command layouts in different games.

Connection types

There are several ways of connecting a keyboard to a system unit (more precisely, to its keyboard controller) using cables, including the standard AT connector commonly found on motherboards, which was eventually replaced by the PS/2 and the USB connection. Prior to the iMac line of systems, Apple used the proprietary Apple Desktop Bus for its keyboard connector      (Sony VGN-FZ460E battery)          .

Wireless keyboards have become popular for their increased user freedom. A wireless keyboard often includes a required combination transmitter and receiver unit that attaches to the computer's keyboard port (see Connection types above). The wireless aspect is achieved either by radio frequency (RF) or by infrared (IR) signals sent and received from both the keyboard and the unit attached to the computer. A wireless keyboard may use an industry standard RF, called Bluetooth. With Bluetooth, the transceiver may be built into the computer       (Sony Vaio VGN-FZ4000 battery)     .

However, a wireless keyboard needs batteries to work and may pose a security problem due to the risk of data "eavesdropping" by hackers. An early example of a consumer wireless keyboard is that of the Olivetti Envision.

Alternative text-entering methods

An on-screen keyboard controlled with the mouse can be used by users with limited mobility         (SONY VGP-BPS13 Battery)              .

Optical character recognition (OCR) is preferable to rekeying for converting existing text that is already written down but not in machine-readable format (for example, a Linotype-composed book from the 1940s). In other words, to convert the text from an image to editable text (that is, a string of character codes), a person could re-type it, or a computer could look at the image and deduce what each character is. OCR technology has already reached an impressive state (for example, Google Book Search) and promises more for the future          (Dell Latitude E6400 battery)       .

Speech recognition converts speech into machine-readable text (that is, a string of character codes). The technology has already reached an impressive state and is already implemented in various software products. For certain uses (e.g., transcription of medical or legal dictation; journalism; writing essays or novels) it is starting to replace the keyboard; however, it does not threaten to replace keyboards entirely anytime soon      (Dell INSPIRON 1525 battery)      .

It can, however, interpret commands (for example, "close window" or "undo that") in addition to text. Therefore, it has theoretical potential to replace keyboards entirely (whereas OCR replaces them only for a certain kind of task).

Pointing devices can be used to enter text or characters in contexts where using a physical keyboard would be inappropriate or impossible         (Dell INSPIRON E1505 battery)    .

These accessories typically present characters on a display, in a layout that provides fast access to the more frequently used characters or character combinations. Popular examples of this kind of input are Graffiti, Dasher and on-screen virtual keyboards.

Other issues

Keystroke hacking

Keystroke logging (often called keylogging) is a method of capturing and recording user keystrokes    (ACER ASPIRE 5020 battery) .

While it is used legally to measure employee productivity on certain clerical tasks, or by law enforcement agencies to find out about illegal activities, it is also used by hackers for various illegal or malicious acts. Hackers use keyloggers as a means to obtain passwords or encryption keys and thus bypass other security measures.

Keystroke logging can be achieved by both hardware and software means. Hardware key loggers are attached to the keyboard cable or installed inside standard keyboards         (ACER TRAVELMATE 2300 battery)  .

Software keyloggers work on the target computer’s operating system and gain unauthorized access to the hardware, hook into the keyboard with functions provided by the OS, or use remote access software to transmit recorded data out of the target computer to a remote location. Some hackers also use wireless keylogger sniffers to collect packets of data being transferred from a wireless keyboard and its receiver, and then they crack the encryption key being used to secure wireless communications between the two devices       (ACER ASPIRE 3020 battery)             .

Anti-spyware applications are able to detect many keyloggers and cleanse them. Responsible vendors of monitoring software support detection by anti-spyware programs, thus preventing abuse of the software. Enabling a firewall does not stop keyloggers per se, but can possibly prevent transmission of the logged material over the net if properly configured. Network monitors (also known as reverse-firewalls) can be used to alert the user whenever an application attempts to make a network connection      (ACER TRAVELMATE 4500 battery)        .

This gives the user the chance to prevent the keylogger from "phoning home" with his or her typed information. Automatic form-filling programs can prevent keylogging entirely by not using the keyboard at all. Most keyloggers can be fooled by alternating between typing the login credentials and typing characters somewhere else in the focus window      (Dell XT832 Battery)     .

Wireless keystroke hacking

Also known as remote keylogging or wireless keylogging.

In their research “Compromising Electromagnetic Emanations of Wired Keyboard”  Vuagnoux and Pasini have provided evidence that modern keyboards radiate compromising electromagnetic emanations. The four techniques presented in their paper prove that these basic devices are generally not sufficiently protected against compromising emanations         (Dell Latitude XT2 Tablet PC Battery)   .

Additionally, they showed that these emanations can be captured with relatively inexpensive equipment and keystrokes are recovered  not only in the semi-anechoic chamber but in practical environments as well (e.g office). The consequences of these attacks are that compromising electromagnetic emanations of keyboards still represent a security risk. PS/2, USB, laptop and wireless keyboards are vulnerable           (HP Pavilion DV4 Battery)         .

Moreover, there is no software patch to avoid these attacks. Hardware has to be replaced in order to obtain safe devices. Due to cost pressure in the design and lack of knowledge, manufacturers do not systematically protect keyboards. Even in the practical space of an office with multiple keyboards, Vuagnoux and Pasini were able to deduce a specific fingerprint for every keyboard. When multiple keyboards are radiating at the same time, they are able to identify and differentiate them         (HP Pavilion DV7 Battery)     .

Physical injury

Proper ergonomic design of computer keyboard desks is necessary to prevent repetitive strain injuries, which can develop over time and can lead to long-term disability.

The use of any keyboard may cause serious injury (that is, carpal tunnel syndrome or other repetitive strain injury) to hands, wrists, arms, neck or back. The risks of injuries can be reduced by taking frequent short breaks to get up and walk around a couple of times every hour         (Toshiba PA3399U-2BRS battery)       .

As well, users should vary tasks throughout the day, to avoid overuse of the hands and wrists. When inputting at the keyboard, a person should keep the shoulders relaxed with the elbows at the side, with the keyboard and mouse positioned so that reaching is not necessary. The chair height and keyboard tray should be adjusted so that the wrists are straight, and the wrists should not be rested on sharp table edges. Wrist or palm rests should not be used while typing    (Sony VGN-FW11S Battery)        .

Some Adaptive technology ranging from special keyboards, mouse replacements and pen tablet interfaces to speech recognition software can reduce the risk of injury. Pause software reminds the user to pause frequently. Switching to a much more ergonomic mouse, such as a vertical mouse or joystick mouse may provide relief. Switching from using a mouse to using a stylus pen with graphic tablet or a trackpad such as a Smart Cat trackpad can lessen the repetitive strain on the arms and hands        (Sony VGP-BPS13B/B Battery)      .

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This article is about personal computers in general. For computers generally referred to as "PCs", see IBM PC compatible. For hardware components dealing with personal computers, see Personal computer hardware      (Dell XPS M1210 Battery)          .

A personal computer (PC) is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user with no intervening computer operator. This is in contrast to the batch processing or time-sharing models which allowed large expensive mainframe systems to be used by many people, usually at the same time, or large data processing systems which required a full-time staff to operate efficiently         (Dell Studio XPS 1340 Battery)          .

It is also in contrast with the more recent trend of controlling software availability through an intervening third party such as the Apple App Store.

A personal computer may be a desktop computer, a laptop, a tablet PC, or a handheld PC (also called a palmtop). The most common microprocessors in personal computers are x86-compatible CPUs        (Dell Studio XPS 1640 Battery)       .

Software applications for personal computers include word processing, spreadsheets, databases, Web browsers and e-mail clients, games, and myriad personal productivity and special-purpose software applications. Modern personal computers often have connections to the Internet, allowing access to the World Wide Web and a wide range of other resources      (Dell Vostro 1710 Battery)        .

A PC may be used at home or in an office. Personal computers may be connected to a local area network (LAN), either by a cable or a wireless connection.

While early PC owners usually had to write their own programs to do anything useful with the machines, today's users have access to a wide range of commercial and non-commercial software, which is provided in ready-to-run or ready-to-compile form. Since the 1980s, Microsoft and Intel have dominated much of the personal computer market, first with MS-DOS and then with the Wintel platform       (ASUS EEE PC900 battery) .


This section needs additional citations for verification.

Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (September 2008)

Main article: History of personal computers   (Dell RM791 battery)

In what was later to be called The Mother of All Demos, SRI researcher Douglas Englebart in 1968 gave a preview of what would become the staples of daily working life in the 21st century - e-mail, hypertext, word processing, video conferencing, and the mouse. The demonstration required technical support staff and a mainframe time-sharing computer that were far too costly for individual business use at the time        (Sony VGP-BPS13 battery)      .

By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person.

HP 9830 was an early desktop computer with printer      (sony vgp-bpl9 battery)

In the 1970s Hewlett Packard introduced fully BASIC programmable computers that fit entirely on top of a desk, including a keyboard, a small one-line display and printer. The Wang 2200 of 1973 had a full-size CRT and cassette tape storage. The IBM 5100 in 1975 had a small CRT display and could be programmed in BASIC and APL. These were generally expensive specialized computers sold for business or scientific uses         (Sony VGP-BPL11 battery)     .

The introduction of the microprocessor, a single chip with all the circuitry that formerly occupied large cabinets, led to the proliferation of personal computers after 1975.

Early personal computers - generally called microcomputers - were sold often in kit form and in limited volumes, and were of interest mostly to hobbyists and technicians        (Sony VGP-BPL15 battery)         .

Minimal programming was done with toggle switches to enter instructions, and output was provided by front panel lamps. Practical use required peripherals such as keyboards, computer terminals, disk drives, and printers. Micral N was the earliest commercial, non-kit microcomputer based on a microprocessor, the Intel 8008          (Dell Inspiron E1505 battery )        .

It was built starting in 1972 and about 90,000 units were sold. The first true Personal Computer was the Sphere 1 computer, created in Bountiful, Utah in 1975 by computer pioneer Michael D. Wise (1949-2002). At first, Sphere 1 was sold as a kit, but was later sold as fully assembled PC. The Sphere 1 qualified as The First Personal Computer because it included a keyboard, a number pad, and a monitor         (Dell Latitude E6400 battery)         .

In 1976 Steve Jobs and Steve Wozniak sold the Apple I computer circuit board, which was fully prepared and contained about 30 chips. The first successfully mass marketed personal computer was the Commodore PET introduced in January 1977, which bore a striking resemblance to Sphere 1 of two years earlier. It was soon followed by the TRS-80 from Radio Shack and the popular Apple II. Mass-market pre-assembled computers allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware       (HP Pavilion dv6000 Battery)        .

Through the late 1970s and into the 1980s, computers were developed for household use, with software for personal productivity, programming and games. One such machine, the Commodore 64, totaled 17 million units sold, making it the best-selling single personal computer model of all time       (Hp Pavilion dv3-1000 battery)       .

Somewhat larger and more expensive systems (although still low-cost compared with minicomputers and mainframes) were aimed at office and small business use. Workstations are characterized by high-performance processors and graphics displays, with large local disk storage, networking capability, and running under a multitasking operating system        (Dell Precision M70 Battery)        .

In 1984, Dr. Mark Dean created a device called the ISA systems bus, which allows a personal computer to have several machines connected to it at once, such as a printer and scanner or modem. ISA is widely used today and Dean also received the Black Engineer of the Year President’s Award in 1997 for his contribution . However, card slots already existed before the ISA bus of the IBM-PC in the Apple         (Acer Aspire One battery)         .

IBM 5150 as of 1981

Eventually due to the influence of the IBM-PC on the personal computer market, personal computers and home computers lost any technical distinction. Business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of a few years before        (Toshiba Satellite L305 Battery)        .

Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of personal computers used at home.

Market and sales

See also: Market share of leading PC vendors

Personal computers worldwide in million distinguished by developed and developing world    (Toshiba Satellite Pro M15 Battery)

In 2001, 125 million personal computers were shipped in comparison to 48 thousand in 1977. More than 500 million personal computers were in use in 2002 and one billion personal computers had been sold worldwide from the mid-1970s up to this time. Of the latter figure, 75 percent were professional or work related, while the rest were sold for personal or home use. About 81.5 percent of personal computers shipped had been desktop computers, 16.4 percent laptops and 2.1 percent servers       (Toshiba Satellite M65 battery)          .

The United States had received 38.8 percent (394 million) of the computers shipped, Europe 25 percent and 11.7 percent had gone to the Asia-Pacific region, the fastest-growing market as of 2002. The second billion was expected to be sold by 2008. Almost half of all the households in Western Europe had a personal computer and a computer could be found in 40 percent of homes in United Kingdom, compared with only 13 percent in 1985         (Toshiba Satellite T4900 Battery)        .

The global personal computer shipments were 264 million units in the year 2007, according to iSuppli,  up 11.2 percent from 239 million in 2006.  In 2004, the global shipments were 183 million units, an 11.6 percent increase over 2003. In 2003, 152.6 million computers were shipped, at an estimated value of $175 billion. In 2002, 136.7 million PCs were shipped, at an estimated value of $175 billion     (Toshiba PA3399U-2BRS battery)        .

In 2000, 140.2 million personal computers were shipped, at an estimated value of $226 billion.  Worldwide shipments of personal computers surpassed the 100-million mark in 1999, growing to 113.5 million units from 93.3 million units in 1998.  In 1999, Asia had 14.1 million units shipped        (Toshiba Satellite A200 Battery)       .

As of June 2008, the number of personal computers in use worldwide hit one billion, while another billion is expected to be reached by 2014. Mature markets like the United States, Western Europe and Japan accounted for 58 percent of the worldwide installed PCs. The emerging markets were expected to double their installed PCs by 2012 and to take 70 percent of the second billion PCs. About 180 million computers (16 percent of the existing installed base) were expected to be replaced and 35 million to be dumped into landfill in 2008. The whole installed base grew 12 percent annually      (Toshiba Satellite 1200 Battery)       .

In the developed world, there has been a vendor tradition to keep adding functions to maintain high prices of personal computers. However, since the introduction of the One Laptop per Child foundation and its low-cost XO-1 laptop, the computing industry started to pursue the price too. Although introduced only one year earlier, there were 14 million netbooks sold in 2008     (Toshiba NB100 Battery).

Besides the regular computer manufacturers, companies making especially rugged versions of computers have sprung up, offering alternatives for people operating their machines in extreme weather or environments.

Average selling price

For Microsoft Windows systems, the average selling price (ASP) showed a decline in 2008/2009, possibly due to low-cost netbooks, drawing $569 for desktop computers and $689 for laptops at U.S. retail in August 2008. In 2009, ASP had further fallen to $533 for desktops and to $602 for notebooks by January and to $540 and $560 in February       (Toshiba Satellite M300 Battery)         .

According to research firm NPD, the average selling price of all Windows portable PCs has fallen from $659 in October 2008 to $519 in October 2009.



Sun SPARCstation 1+, 25 MHz RISC processor from early 1990s

Main article: Workstation       (Dell INSPIRON 1525 battery)

A workstation is a high-end personal computer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems. Workstations are used for tasks such as computer-aided design, drafting and modelling, computation-intensive scientific and engineering calculations, image processing, architectural modelling, and computer graphics for animation and motion picture visual effects      (SONY VAIO VGN-FZ280E Battery)        .

Desktop computer

Main article: Desktop computer

Dell OptiPlex desktop computer

Prior to the wide spread of PCs a computer that could fit on a desk was considered remarkably small. Today the phrase usually indicates a particular style of computer case          (SONY VAIO VGN-FZ410 Battery)      .

Desktop computers come in a variety of styles ranging from large vertical tower cases to small form factor models that can be tucked behind an LCD monitor. In this sense, the term 'desktop' refers specifically to a horizontally-oriented case, usually intended to have the display screen placed on top to save space on the desk top. Most modern desktop computers have separate screens and keyboards       (SONY VAIO VGN-FZ160 Battery)         .

Single unit

Single unit PCs (also known as all-in-one PCs) are a subtype of desktop computers, which combine the monitor and case of the computer within a single unit. The monitor often utilizes a touchscreen as an optional method of user input, however detached keyboards and mice are normally still included. The inner components of the PC are often located directly behind the monitor, and many are built similarly to laptops       (SONY VAIO VGN-FZ38M Battery)       .


Main article: Nettop

A subtype of desktops, called nettops, was introduced by Intel in February 2008 to describe low-cost, lean-function, desktop computers. A similar subtype of laptops (or notebooks) are the netbooks (see below). These feature the new Intel Atom processor which specially enables them to consume less power and to be built into small enclosures         (SONY VAIO VGN-FZ21m Battery)  .


Main article: Laptop

Acer 8920 Gemstone Laptop.

A laptop computer or simply laptop, also called a notebook computer or sometimes a notebook, is a small personal computer designed for portability. Usually all of the interface hardware needed to operate the laptop, such as USB ports (previously parallel and serial ports), graphics card, sound channel, etc., are built in to a single unit        (SONY VAIO VGN-FZ18m Battery)      .

Laptops contain high capacity batteries that can power the device for extensive periods of time, enhancing portability. Once the battery charge is depleted, it will have to be recharged through a power outlet. In the interest of saving power, weight and space, they usually share RAM with the video channel, slowing their performance compared to an equivalent desktop machine     (SONY VAIO VGN-FZ11m Battery)         .

One main drawback of the laptop is sometimes, due to the size and configuration of components, relatively little can be done to upgrade the overall computer from its original design. Internal upgrades are either not manufacturer recommended, can damage the laptop if done with poor care or knowledge, or in some cases impossible, making the desktop PC more modular. Some internal upgrades, such as memory and hard disks upgrades are often easy, a display or keyboard upgrade is usually impossible        (SONY VAIO VGN-FZ11z Battery)          .

The laptop has the same access as the desktop to the wide variety of devices, such as external displays, mice, cameras, storage devices and keyboards, which may be attached externally through USB ports and other less common ports such as external video.

A subtype of notebooks, called subnotebooks, are computers with most of the features of a standard laptop computer but smaller          (SONY VAIO VGN-FZ11l Battery)      .

They are larger than hand-held computers, and usually run full versions of desktop/laptop operating systems. Ultra-Mobile PCs (UMPC) are usually considered subnotebooks, or more specifically, subnotebook Tablet PCs (see below). Netbooks are sometimes considered in this category, though they are sometimes separated in a category of their own (see below).

Desktop replacements, meanwhile, are large laptops meant to replace a desktop computer while keeping the mobility of a laptop. Entertainment laptops emphasize large, HDTV-resolution screens and video processing capabilities     (SONY VAIO VGN-FZ31z Battery)        .


Main article: Netbook

An HP netbook

Netbooks (also called mini notebooks or subnotebooks) are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as "companion devices," that is, to augment a user's other computer access    (Dell Studio 1555 Battery)       .

Walt Mossberg called them a "relatively new category of small, light, minimalist and cheap laptops."  By August 2009, CNET called netbooks "nothing more than smaller, cheaper notebooks."

At their inception in late 2007 — as smaller notebooks optimized for low weight and low cost— netbooks omitted key features (e.g., the optical drive), featured smaller screens and keyboards, and offered reduced specification and computing power    (Dell Vostro 1720 Battery)        .

Over the course of their evolution, netbooks have ranged in size from below 5 in to over 13 in, and from ~1 kg (2-3 pounds). Often significantly less expensive than other laptops,by mid-2009, netbooks had been offered to users "free of charge", with an extended service contract purchase of a cellular data plan      (Dell Vostro 1500 Battery)       .

In the short period since their appearance, netbooks have grown in size and features, now converging with new smaller, lighter notebooks. By mid 2009, CNET noted "the specs are so similar that the average shopper would likely be confused as to why one is better than the other," noting "the only conclusion is that there really is no distinction between the devices      (Dell Latitude D830 Battery)        ."

Tablet PC

Main article: Tablet PC

HP Compaq tablet PC with rotating/removable keyboard.

A tablet PC is a notebook or slate-shaped mobile computer, first introduced by Pen computing in the early 90s with their PenGo Tablet Computer and popularized by Microsoft      (Dell Latitude D620 Battery)      .

Its touchscreen or graphics tablet/screen hybrid technology allows the user to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse. The form factor offers a more mobile way to interact with a computer. Tablet PCs are often used where normal notebooks are impractical or unwieldy, or do not provide the needed functionality         (SONY VAIO VGN-FZ150E Battery)         .

As technology and functionality continue to progress, prototype tablet PCs will continue to emerge. The Microsoft Courier, a personal business device, has two 7" monitors that support multi-touch gestures, Wi-Fi capabilities and has a built-in camera. The device looks to be a replacement to traditional planners while offering what most digital planners cannot, two pages and large writing spaces. This particular device, however, has been recently abandoned and the market is currently being led by the popular iPad from Apple Inc         (Dell Studio 1735 Battery)       .

Ultra-Mobile PC

Main article: Ultra-Mobile PC

Samsung Q1 Ultra-Mobile PC.

The ultra-mobile PC (UMPC) is a specification for a small form factor of tablet PCs. It was developed as a joint development exercise by Microsoft, Intel, and Samsung, among others. Current UMPCs typically feature the Windows XP, Windows Vista, Windows 7, or Linux operating system and low-voltage Intel Atom or VIA C7-M processors        (Dell Inspiron 300M Battery)    .

Home theater PC

Main article: Home theater PC

Antec Fusion V2 home theater PC with keyboard on top.

A home theater PC (HTPC) is a convergence device that combines the functions of a personal computer and a digital video recorder. It is connected to a television or a television-sized computer display and is often used as a digital photo, music, video player, TV receiver and digital video recorder      (Dell Studio 1737 battery)       .

Home theater PCs are also referred to as media center systems or media servers. The general goal in a HTPC is usually to combine many or all components of a home theater setup into one box. They can be purchased pre-configured with the required hardware and software needed to add television programming to the PC, or can be cobbled together out of discrete components as is commonly done with MythTV, Windows Media Center, GB-PVR, SageTV, Famulent or LinuxMCE      (Dell XPS M1530 battery)      .

Pocket PC

Main article: Pocket PC

An O2 pocket PC

A pocket PC is a hardware specification for a handheld-sized computer (personal digital assistant) that runs the Microsoft Windows Mobile operating system. It may have the capability to run an alternative operating system like NetBSD or Linux. It has many of the capabilities of modern desktop PCs       (Dell XPS M2010 battery)          .

Currently there are tens of thousands of applications for handhelds adhering to the Microsoft Pocket PC specification, many of which are freeware. Some of these devices also include mobile phone features. Microsoft compliant Pocket PCs can also be used with many other add-ons like GPS receivers, barcode readers, RFID readers, and cameras. In 2007, with the release of Windows Mobile 6, Microsoft dropped the name Pocket PC in favor of a new naming scheme       (Dell Vostro 1000 battery)       .

Devices without an integrated phone are called Windows Mobile Classic instead of Pocket PC. Devices with an integrated phone and a touch screen are called Windows Mobile Professional.


The motherboard, also referred to as systemboard or mainboard, is the primary circuit board within a personal computer. Many other components connect directly or indirectly to the motherboard        (HP Pavilion dv9000 battery)         .

Motherboards usually contain one or more CPUs, supporting circuitry - usually integrated circuits (ICs) - providing the interface between the CPU memory and input/output peripheral circuits, main memory, and facilities for initial setup of the computer immediately after power-on (often called boot firmware or, in IBM PC compatible computers, a BIOS). In many portable and embedded personal computers, the motherboard houses nearly all of the PC's core components       (Hp 520 battery)       .

Often a motherboard will also contain one or more peripheral buses and physical connectors for expansion purposes. Sometimes a secondary daughter board is connected to the motherboard to provide further expandability or to satisfy space constraints.

Main memory

Main article: Primary storage

A PC's main memory is fast storage that is directly accessible by the CPU, and is used to store the currently executing program and immediately needed data. PCs use semiconductor random access memory (RAM) of various kinds such as DRAM, SDRAM or SRAM as their primary storage       (SONY VGP-BPS13 Battery)      .

Which exact kind depends on cost/performance issues at any particular time. Main memory is much faster than mass storage devices like hard disks or optical discs, but is usually volatile, meaning it does not retain its contents (instructions or data) in the absence of power, and is much more expensive for a given capacity than is most mass storage. Main memory is generally not suitable for long-term or archival data storage     (SONY VAIO VGN-FZ Battery)   .

Hard disk

Main article: Hard disk drive

A Western Digital 250 GB hard disk drive.

Mass storage devices store programs and data even when the power is off; they do require power to perform read and write functions during usage. Although flash memory has dropped in cost, the prevailing form of mass storage in personal computers is still the hard disk       (Dell RM791 battery)        .

The disk drives use a sealed head/disk assembly (HDA) which was first introduced by IBM's "Winchester" disk system. The use of a sealed assembly allowed the use of positive air pressure to drive out particles from the surface of the disk, which improves reliability.

If the mass storage controller provides for expandability, a PC may also be upgraded by the addition of extra hard disk or optical disc drives. For example, BD-ROMs, DVD-RWs, and various optical disc recorders may all be added by the user to certain PCs     (Toshiba Portege R200 Battery) .

Standard internal storage device connection interfaces are PATA, Serial ATA, SCSI

Video card

Main article: Video card

ATI Radeon video card

The video card - otherwise called a graphics card, graphics adapter or video adapter - processes and renders the graphics output from the computer to the computer display, and is an essential part of the modern computer. On older models, and today on budget models, graphics circuitry tended to be integrated with the motherboard but, for modern flexible machines, they are supplied in PCI, AGP, or PCI Express format        (Toshiba Satellite M60 battery)          .

When the IBM PC was introduced, most existing business-oriented personal computers used text-only display adapters and had no graphics capability. Home computers at that time had graphics compatible with television signals, but with low resolution by modern standards owing to the limited memory available to the eight-bit processors available at the time      (Dell Studio 1555 Battery)      .

Visual display unit

Main article: Visual display unit

A flat-panel LCD monitor.

A visual display unit (or monitor) is a piece of electrical equipment, usually separate from the computer case, which displays viewable images generated by a computer without producing a permanent record      (Dell Vostro 1400 Battery)         .

The word "monitor" is used in other contexts; in particular in television broadcasting, where a television picture is displayed to a high standard. A computer display device is usually either a cathode ray tube or some form of flat panel such as a TFT LCD. The monitor comprises the display device, circuitry to generate a picture from electronic signals sent by the computer, and an enclosure or case  (Dell Vostro 1500 Battery)      .

Within the computer, either as an integral part or a plugged-in Expansion card, there is circuitry to convert internal data to a format compatible with a monitor. The images from monitors originally contained only text, but as Graphical user interfaces emerged and became common, they began to display more images and multimedia content     (Toshiba Satellite Pro M50 Battery)     .


Main article: Keyboard (computing)

A computer keyboard

In computing, a keyboard is an arrangement of buttons that each correspond to a function, letter, or number. They are the primary devices of inputing text. In most cases, they contain an array of keys specifically organized with the corresponding letters, numbers, and functions printed or engraved on the button      (Dell Vostro 1510 Battery)        .

They are generally designed around an operators language, and many different versions for different languages exist. In English, the most common layout is the QWERTY layout, which was originally used in typewriters. They have evolved over time, and have been modified for use in computers with the addition of function keys, number keys, arrow keys, and OS specific keys       (Dell Latitude XT2 Tablet PC Battery)       .

Often, specific functions can be achieved by pressing multiple keys at once or in succession, such as inputing characters with accents or opening a task manager. Programs use keyboard shotcuts very differently and all use different keyboard shortcuts for different program specific operations, such as refreshing a web page in a web browser or selecting all text in a word processor     (Dell Vostro A90 Battery)          .


Main article: Mouse (computing)

Apple Mighty Mouse that detects the right and left clicks through what appears to be one large button.

A Mouse on a computer is a small, slidable device that users hold and slide around to point at, click on, and sometimes drag objects on screen in a graphical user interface using a pointer on screen. Almost all Personal Computers have mice        ( HP Pavilion DV7 Battery)         .

It may be plugged into a computer's rear mouse socket, or as a USB device, or, more recently, may be connected wirelessly via a USB antenna or Bluetooth antenna. In the past, they had a single button that users could press down on the device to "click" on whatever the pointer on the screen was hovering over          ( HP Pavilion DV7 Battery)      .

Now, however, many Mice have two or three buttons(possibly more); a "right click" function button on the mouse, which performs a secondary action on a selected object, and a scroll wheel, which users can rotate using their fingers to "scroll" up or down. The scroll wheel can also be pressed down, and therefore be used as a third button. Some mouse wheels may be tilted from side to side to allow sideways scrolling. Different programs make use of these functions differently, and may scroll horizontally by default with the scroll wheel, open different menus with different buttons, among others. These functions may be user defined through software utilities   (Toshiba Satellite Pro M10 Battery)        .

Mice traditionally detected movement and communicated with the computer with an internal "mouse ball"; and used optical encoders to detect rotation of the ball and tell the computer where the mouse has moved. However, these systems were subject to low durability, accuracy and required internal cleaning. Modern mice use optical technology to directly trace movement of the surface under the mouse and are much more accurate, durable and almost maintenace free. They work on a wider variety of surfaces and can even operate on walls, ceilings or other non-horizontal surfaces      (Dell Inspiron 300M Battery)      .

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Dell Inc: (NASDAQ: Dell, HKEX: 4331) is a multinational information technology corporation based in Round Rock, Texas, United States, that develops, sells and supports computers and related products and services. Bearing the name of its founder, Michael Dell, the company is one of the largest technological corporations in the world, employing more than 96,000 people worldwide. Dell is listed at #38 on the Fortune 500 (2010). Fortune also lists Dell as the #5 most admired company in its industry       (Dell XPS M1210 Battery)        .

Dell has grown by both organic and inorganic means since its inception—notable mergers and acquisitions including Alienware (2006) and Perot Systems (2009). As of 2009, the company sold personal computers, servers, data storage devices, network switches, software, and computer peripherals. Dell also sells HDTVs, cameras, printers, MP3 players and other electronics built by other manufacturers. The company is well known for its innovations in supply chain management and electronic commerce       (Dell Studio XPS 1340 Battery)            .

On May 3, 2010, Fortune Magazine listed Dell as the 38th largest company in the United States and the 5th largest company in Texas by total revenue. It is the 2nd largest non-oil company in Texas (behind AT&T) and the largest company in the Austin area.


Main article: History of Dell

Founder Michael Dell with his PCs Limited (the precursor to Dell Inc.) prototype, which is now housed at the Smithsonian Institution

Dell traces its origins to 1984, when Michael Dell created PCs Limited while a student at the University of Texas at Austin. The dorm-room headquartered company sold IBM PC-compatible computers built from stock components       (Dell Studio XPS 1640 Battery)    .

Michael Dell started trading in the belief that by selling personal computer systems directly to customers, PCs Limited could better understand customers' needs and provide the most effective computing solutions to meet those needs. Michael Dell dropped out of school in order to focus full-time on his fledgling business, after getting about $300,000 in expansion-capital from his family    (Dell Vostro 1710 Battery)          .

In 1985, the company produced the first computer of its own design — the "Turbo PC", sold for US$795.  PCs Limited advertised its systems in national computer magazines for sale directly to consumers and custom assembled each ordered unit according to a selection of options. The company grossed more than $73 million in its first year of trading       (ASUS EEE PC900 battery) .

The company changed its name to "Dell Computer Corporation" in 1988 and began expanding globally—first in Ireland. In June 1988, Dell's market capitalization grew by $30 million to $80 million from its June 22 initial public offering of 3.5 million shares at $8.50 a share. In 1992, Fortune magazine included Dell Computer Corporation in its list of the world's 500 largest companies, making Michael Dell the youngest CEO of a Fortune 500 company ever       (Dell RM791 battery)        .

In 1996, Dell began selling computers via its web site, and in 2002, Dell expanded its product line to include televisions, handhelds, digital audio players, and printers. Dell's first acquisition occurred in 1999 with the purchase of ConvergeNet Technologies. In 2003, the company was rebranded as simply "Dell Inc." to recognize the company's expansion beyond computers. From 2004 to 2007, Michael Dell stepped aside as CEO, while long-time Dell employee Kevin Rollins took the helm       (Sony VGP-BPS13 battery)       .

During that time, Dell acquired Alienware, which introduced several new items to Dell products, including AMD microprocessors. To prevent cross-market products, Dell continues to run Alienware as a separate entity but still a wholly-owned subsidiary.

Lackluster performance, however, in its lower-end computer business prompted Michael Dell to take on the role of CEO again. The founder announced a change campaign called "Dell 2.0," reducing headcount and diversifying the company's product offerings. The company acquired EqualLogic on January 28, 2008 to gain a foothold in the iSCSI storage market. Because Dell already had an efficient manufacturing process, integrating EqualLogic's products into the company drove manufacturing prices down        (sony vgp-bpl9 battery)            .

In 2009, Dell acquired Perot Systems, a technology services and outsourcing company founded by H. Ross Perot.

On September 21, 2009, Dell announced its intent to acquire Perot Systems (based in Plano, Texas) in a reported $3.9 billion deal. Perot Systems brought applications development, systems integration, and strategic consulting services through its operations in the U.S. and 10 other countries. In addition, it provided a variety of business process outsourcing services, including claims processing and call center operations        (Sony VGP-BPL11 battery)       .

On August 16, 2010, Dell announced its intent to acquire the data storage company 3PAR. On September 2, 2010 Hewlett-Packard offered $33 a share, which Dell declined to match.

Dell Facilities

Dell is headquartered in Round Rock, Texas

Dell's headquarters are located in Round Rock, Texas.  As of 2010 the company employs about 16,000 people in the facility,which has 2,100,000 square feet (195,000 m2) of space. As of 1999 almost half of the general fund of the City of Round Rock originates from sales taxes generated from the Dell headquarters      (Sony VGP-BPL15 battery)      .

The company previously had its headquarters in the Arboretum complex in northern Austin, Texas. In 1989 Dell occupied 127,000 square feet (11,800 m2) in the Arboretum complex.In 1990 Dell had 1,200 employees in its headquarters. In 1993 Dell submitted a document to Round Rock officials, titled "Dell Computer Corporate Headquarters, Round Rock, Texas, May 1993 Schematic Design." Despite the filing, during that year the company said that it was not going to move its headquarters    (Dell Inspiron E1505 battery ) .

In 1994 Dell announced that it was moving most of its employees out of the Arboretum, but that it was going to continue to occupy the top floor of the Arboretum and that the company's official headquarters address would continue to be the Arboretum. The top floor continued to hold Dell's board room, demonstration center, and visitor meeting room. Less than one month prior to August 29, 1994, Dell moved 1,100 customer support and telephone sales employees to Round Rock. Dell's lease in the Arboretum had been scheduled to expire in 1994      (Dell Latitude E6400 battery)          .

The company sponsors Dell Diamond, the home stadium of the Round Rock Express, the AAA minor league baseball affiliate of the Houston Astros major league baseball team.

By 1996 Dell was moving its headquarters to Round Rock. As of January 1996 3,500 people still worked at the then-current Dell headquarters. One building of the Round Rock headquarters, Round Rock 3, had space for 6,400 employees and was scheduled to be completed in November 1996. In 1998 Dell announced that it was going to add two buildings to its Round Rock complex, adding 1,600,000 square feet (149,000 m2) of office space to the complex      (HP Pavilion dv6000 Battery)          .

In 2000 Dell announced that it would lease 80,000 square feet (7,400 m2) of space in the Las Cimas office complex in unincorporated Travis County, Texas, between Austin and West Lake Hills, to house the company's executive offices and corporate headquarters. 100 senior executives were scheduled to work in the building by the end of 2000.  In January 2001 the company leased the space in Las Cimas 2, located along Loop 360. Las Cimas 2 housed Dell's executives, the investment operations, and some corporate functions         (Hp Pavilion dv3-1000 battery)        .

Dell also had an option for 138,000 square feet (12,800 m2) of space in Las Cimas 3.  After a slowdown in business required reducing employees and production capacity, Dell decided to sublease its offices in two buildings in the Las Cimas office complex. In 2002 Dell announced that it planned to sublease its space to another tenant; the company planned to move its headquarters back to Round Rock once a tenant was secured.  By 2003 Dell moved its headquarters back to Round Rock      (Dell Precision M70 Battery)       .

It leased all of Las Cimas I and II, with a total of 312,000 square feet (29,000 m2), for about a seven year period after 2003. By that year roughly 100,000 square feet (9,300 m2) of that space was absorbed by new subtenants.

In 2008 Dell switched the power sources of the Round Rock headquarters to more environmentally friendly ones, with 60% of the total power coming from TXU Energy wind farms and 40% coming from the Austin Community Landfill gas-to-energy plant operated by Waste Management, Inc         (Acer Aspire One battery)          .

Dell facilities in the United States are located in Austin, Texas; Nashville, Tennessee; Oklahoma City, Oklahoma; Winston-Salem, North Carolina; and Miami, Florida. Facilities located abroad include Penang, Malaysia; Xiamen, China; Bangalore, India; Hyderabad, India; Chandigarh, India; Delhi, India; Bracknell, UK; Manila, Philippines  Chennai, India;  Hortolandia, Brazil; ?ód?, Poland  and Limerick, Ireland        (Hp 520 battery)           .


Scope and brands

The corporation markets specific brand names to different market segments.

Its Business/Corporate class represent brands where the company advertises emphasizes long life-cycles, reliability, and serviceability. Such brands include:

OptiPlex (office desktop computer systems)

Vostro (office/small business desktop and notebook systems)

n Series (desktop and notebook computers shipped with Linux or FreeDOS installed)     (Toshiba Satellite L305 Battery)

Latitude (business-focused notebooks)

Precision (workstation systems and high-performance notebooks),[34]

PowerEdge (business servers)

PowerVault (direct-attach and network-attached storage)

PowerConnect (network switches)      (Toshiba Satellite Pro M15 Battery)

Dell/EMC (storage area networks)

EqualLogic (enterprise class iSCSI SANs)

Dell's Home Office/Consumer class emphasizes value, performance, and expandability. These brands include:

Inspiron (budget desktop and notebook computers)

Studio (mainstream desktop and laptop computers)

XPS (high-end desktop and notebook computers)       (Toshiba Satellite M65 battery)

Studio XPS (high-end design-focus of XPS systems and extreme multimedia capability)

Alienware (high-performance gaming systems)

Adamo (high-end luxury laptop)

Dell's Peripherals class includes USB keydrives, LCD televisions, and printers; Dell monitors includes LCD TVs, plasma TVs and projectors for HDTV and monitors. Dell UltraSharp is further a high-end brand of monitors         (Toshiba Satellite T4900 Battery)   .

Dell service and support brands include the Dell Solution Station (extended domestic support services, previously "Dell on Call"), Dell Support Center (extended support services abroad), Dell Business Support (a commercial service-contract that provides an industry-certified technician with a lower call-volume than in normal queues), Dell Everdream Desktop Management ("Software as a Service" remote-desktop management),  and Your Tech Team (a support-queue available to home users who purchased their systems either through Dell's website or through Dell phone-centers)         (Toshiba PA3399U-2BRS battery)         .

Discontinued products and brands include Axim (PDA; discontinued April 9, 2007),  Dimension (home and small office desktop computers; discontinued July 2007), Dell Digital Jukebox (MP3 player; discontinued August 2006), Dell PowerApp (application-based servers), and Dell Omniplex (desktop and tower computers previously supported to run server and desktop operating systems)        (Toshiba Satellite A200 Battery)           .


From its early beginnings, Dell operated as a pioneer in the "configure to order" approach to manufacturing — delivering individual PCs configured to customer specifications. In contrast, most PC manufacturers in those times delivered large orders to intermediaries on a quarterly basis         (Toshiba Satellite 1200 Battery)          .

To minimize the delay between purchase and delivery, Dell has a general policy of manufacturing its products close to its customers. This also allows for implementing a just-in-time (JIT) manufacturing approach, which minimizes inventory costs. Low inventory is another signature of the Dell business model — a critical consideration in an industry where components depreciate very rapidly    (Toshiba NB100 Battery)            .

Dell's manufacturing process covers assembly, software installation, functional testing (including "burn-in"), and quality control. Throughout most of the company's history, Dell manufactured desktop machines in-house and contracted out manufacturing of base notebooks for configuration in-house.  However, the company's approach has changed. The 2006 Annual Report states "we are continuing to expand our use of original design manufacturing partnerships and manufacturing outsourcing relationships." The Wall Street Journal reported in September, 2008 that "Dell has approached contract computer manufacturers with offers to sell" their plants         (Toshiba Satellite M300 Battery)         .

Assembly of desktop computers for the North American market formerly took place at Dell plants in Austin, Texas (original location) and Lebanon, Tennessee (opened in 1999). The plant in Winston-Salem, North Carolina (opened in 2005) is scheduled to cease operations in January 2011, while the Miami, Florida facility of its Alienware subsidiary remains in operation. Dell servers come from Austin, Texas            (Dell INSPIRON 1525 battery)          .

Dell's desktop plant in Austin, Texas was shut down in 2008. It closed its desktop manufacturing in Lebanon in early 2009. The last major U.S. plant in North Carolina is scheduled to close in January 2011.  It is expected that most of the work carried out in North Carolina will be transferred to contract manufacturers in Asia and Mexico, though Dell said some of the work will move to its own factories overseas        (SONY VAIO VGN-FZ280E Battery)         .

Dell assembles computers for the EMEA market at Limerick in the Republic of Ireland, and employs about 4,500 people in that country. Dell began manufacturing in Limerick in 1991 and went on to become Ireland's largest exporter of goods and its second-largest company and foreign investor. On January 8, 2009, Dell announced that it would move all Dell manufacturing in Limerick to Dell's new plant in the Polish city of ?ód? by January 2010        (SONY VAIO VGN-FZ410 Battery)         .

European Union officials said they would investigate a €52.7million aid package the Polish government used to attract Dell away from Ireland. European Manufacturing Facility 1 (EMF1, opened in 1990) and EMF3 form part of the Raheen Industrial Estate near Limerick. EMF2 (previously a Wang facility, later occupied by Flextronics, situated in Castletroy) closed in 2002,and Dell Inc. has consolidated production into EMF3 (EMF1 now[when?] contains only offices)       (SONY VAIO VGN-FZ160 Battery)             .

Dell's Alienware subsidiary also manufactures PCs in an Athlone, Ireland plant. Construction of EMF4 in ?ód?, Poland has started: Dell started production there in autumn 2007.

Dell opened plants in Penang, Malaysia in 1995, and in Xiamen, China in 1999. These facilities serve the Asian market and assemble 95% of Dell notebooks. Dell Inc. has invested[when?] an estimated $60 million in a new manufacturing unit in Chennai, India, to support the sales of its products in the Indian subcontinent. Indian-made products will bear the "Made in India" mark. In 2007 the Chennai facility had the target of producing 400,000 desktop PCs, and plans envisaged it starting to produce notebook PCs and other products in the second half of 2007         (SONY VAIO VGN-FZ38M Battery)          .

Dell moved desktop and PowerEdge server manufacturing for the South American market from the Eldorado do Sul plant opened in 1999, to a new plant in Hortolandia, Brazil in 2007.

Green initiatives

Dell became the first company in the information technology industry to establish a product-recycling goal (in 2004) and completed the implementation of its global consumer recycling-program in 2006.  On February 6, 2007, the National Recycling Coalition awarded Dell its "Recycling Works" award for efforts to promote producer responsibility      (SONY VAIO VGN-FZ21m Battery)    .

On July 19, 2007, Dell announced that it had exceeded targets in working to achieve a multi-year goal of recovering 275 million pounds of computer equipment by 2009.  The company reported the recovery of 78 million pounds (nearly 40,000 tons) of IT equipment from customers in 2006, a 93-percent increase over 2005; and 12.4% of the equipment Dell sold seven years earlier.

On June 5, 2007 Dell set a goal of becoming the greenest technology company on Earth for the long term. The company launched a zero-carbon initiative that includes       (SONY VAIO VGN-FZ18m Battery)        :

reducing Dell's carbon intensity by 15 percent by 2012

requiring primary suppliers to report carbon emissions data during quarterly business reviews

partnering with customers to build the "greenest PC on the planet"

expanding the company's carbon-offsetting program, "Plant a Tree for Me"       (SONY VAIO VGN-FZ11m Battery)         .

The company introduced the term "The Re-Generation" during a round table in London commemorating 2007 World Environment Day. "The Re-Generation" refers to people of all ages throughout the world who want to "make a difference" in improving the world's environment. Dell also talked about plans to take the lead in setting an environmental standard for the "technology industry" and maintaining that leadership in the future        (SONY VAIO VGN-FZ11z Battery)    .

Dell reports its environmental performance in an annual Corporate Social Responsibility (CSR) Report that follows the Global Reporting Initiative (GRI) protocol. Dell's 2008 CSR report ranked as "Application Level B" as "checked by GRI".

The company aims to reduce its external environmental impact through energy-efficient evolution of products, and also reduce its direct operational impact through energy-efficiency programmes. Internal energy-efficiency programmes reportedly save the company more than $3 million annually in energy-cost savings         (SONY VAIO VGN-FZ11l Battery)       .

The largest component of the company's internal energy-efficiency savings comes through PC power management: the company expects to save $1.8 million in energy costs through using specialised energy-management software on a network of 50,000 PCs.

Technical support

Dell routes technical support queries according to component-type and to the level of support purchased. Dell Inc. brands its service agreements at five levels for their business customers: (1) Basic support provides business-hours telephone support and next business-day on-site support/ Return-to-Base or Collect and Return Services (based on contracts purchased at point of sale); (2) Silver support provides 24×7 telephone support and 4-hour on-site support after telephone-based troubleshooting; (3) Gold support provides additional benefits over and above Silver support; (4) Platinum Plus support provides additional benefits to Gold Support; and (5) two-hour on-site support, offered in select cities         (SONY VAIO VGN-FZ31z Battery)           .

Dell's Consumer division offers 24x7 phone based and online troubleshooting rather than only during business hours in certain markets such as the United States and Canada. On February 4, 2008 Dell launched a revamped services-and-support scheme for businesses named "ProSupport", offering customers more options to tailor services to fit their needs. Rather than take a one-size-fits-all approach, Dell has put together packages of options for each category of its customers: small and medium-sized businesses, large businesses, government, education, and health-care- and life-sciences          (Dell Studio 1555 Battery)          .

Dell now also offers separate support options for IT staff and for non-IT professionals. For the latter, the company offers "how-to" support for software applications, such as Microsoft Office. Dell also offers collaborative support with many third-party software vendors. For Dell-Certified IT departments, Dell offers "fast-track dispatch" of parts and labor and access to a crisis-center to handle major outages, virus-attacks, or problems caused by natural disasters         (Dell Vostro 1720 Battery)        .

Dell has several unique aspects of its support program. For example, computers use "Service Tags" unique alpha-numeric identifiers and '11 digit Express Service codes' (punched into the IVR prompts) to get customers to the appropriate support queue. Agents also utilize DellConnect, (a Citrix/GoToAssist based remote-access tool that gives technicians within Dell Support the ability to access customer computers from a remote location for troubleshooting purposes)         (Dell Vostro 1500 Battery)      .

Commercial aspects


A board of directors of nine people runs the company. Michael Dell, the founder of the company, serves on the board. Other board members include Don Carty, William Gray, Judy Lewent, Klaus Luft, Alex Mandl, Michael A. Miles, and Sam Nunn. Shareholders elect the nine board members at meetings, and those board members who do not get a majority of votes must submit a resignation to the board, which will subsequently choose whether or not to accept the resignation        (Dell Latitude D830 Battery)       .

The board of directors usually sets up five committees having oversight over specific matters. These committees include the Audit Committee, which handles accounting issues, including auditing and reporting; the Compensation Committee, which approves compensation for the CEO and other employees of the company; the Finance Committee, which handles financial matters such as proposed mergers and acquisitions; the Governance and Nominating Committee, which handles various corporate matters (including nomination of the board); and the Antitrust Compliance Committee, which attempts to prevent company practices from violating antitrust laws        (Dell Latitude D620 Battery)         .

The corporate structure and management of Dell extends beyond the board of directors. The Dell Global Executive Management Committee sets strategic directions. Dell has regional senior vice-presidents for countries other than the United States, including David Marmonti for EMEA and Stephen J. Felice for Asia/Japan. As of 2007, other officers included Martin Garvin (senior vice president for worldwide procurement) and Susan E. Sheskey (vice president and Chief Information Officer)      (SONY VAIO VGN-FZ150E Battery)           .


Dell advertisements have appeared in several types of media including television, the Internet, magazines, catalogs and newspapers. Some of Dell Inc's marketing strategies include lowering prices at all times of the year, offering free bonus products (such as Dell printers), and offering free shipping in order to encourage more sales and to stave off competitors. In 2006, Dell cut its prices in an effort to maintain its 19.2% market share        (Dell Studio 1735 Battery)        .

However, this also cut profit-margins by more than half, from 8.7 to 4.3 percent. To maintain its low prices, Dell continues to accept most purchases of its products via the Internet and through the telephone network, and to move its customer-care division to India and El Salvador.

A popular United States television and print ad campaign in the early 2000s featured the actor Ben Curtis playing the part of "Steven", a lightly mischievous blond-haired youth who came to the assistance of bereft computer purchasers. Each television advertisement usually ended with Steven's catch-phrase: "Dude, you're gettin' a Dell!      (Dell Inspiron 300M Battery)        "

A subsequent advertising campaign featured interns at Dell headquarters (with Curtis' character appearing in a small cameo at the end of one of the first commercials in this particular campaign).

A Dell advertising campaign for the XPS line of gaming computers featured in print in the September 2006 issue of Wired. It used as a tagline the common term in Internet and gamer slang: "FTW", meaning "For The Win". However, Dell Inc. soon[when?] dropped the campaign        (Dell Studio 1737 battery)            .

In the first-person shooter game F.E.A.R. Extraction Point, several computers visible on desks within the game have recognizable Dell XPS model characteristics, sometimes even including the Dell logo on the monitors.

In 2007, Dell switched advertising agencies in the US from BBDO to Mother. In July 2007, Dell released new advertising created by Mother to support the Inspiron and XPS lines. The ads featured music from the Flaming Lips and Devo who re-formed especially to record the song in the ad "Work it Out". Also in 2007, Dell began using the slogan "Yours is here" to say that it customizes computers to fit customers' requirements        (Dell XPS M1530 battery)            .

Criticisms of Dell's marketing of laptop security

In 2008, Dell received press coverage over its claim of having the world's most secure laptops, specifically, its Latitude D630 and Latitude D830. At Lenovo's request, the (U.S.) National Advertising Division (NAD) evaluated the claim, and reported that Dell did not have enough evidence to support it       (Dell XPS M2010 battery)         .

Dell kiosks

Starting in 2002, Dell opened kiosk locations in shopping malls across the United States in order to give personal service to customers who preferred this method of shopping to using the Internet or the telephone-system. Despite the added expense, prices at the kiosks match or beat prices available through other retail channels. Starting in 2005, Dell expanded kiosk locations to include shopping malls across Australia, Canada, Singapore and Hong Kong         (Dell Vostro 1000 battery)        .

On January 30, 2008, Dell shut down all 140 kiosks in the U.S. due to expansion into retail stores such as Wal-Mart, Best Buy, and Staples all over the world.

Dell stores in the United States of America

In 2006, Dell Inc. opened one full store, 3,000-square-foot (280 m2) in area, at NorthPark Center in Dallas, Texas. It operates the retail outlet seven days a week to display about 36 models, including PCs and televisions. As at the kiosks, customers can only see demonstration-computers and place orders through agents. Dell then delivers purchased items just as if the customer had placed the order by phone or over the Internet       (HP Pavilion dv9000 battery)        .

Dell Inc. planned to use the Dallas store to house about three times as many products as it displayed in more than 160 kiosks in malls and airports.  In addition to showcasing products, the stores also support on-site warranties and non-warranty service ("Dell Solution Station"). Services offered include repairing computer video-cards and removing spyware from hard drives.

On February 14, 2008, Dell closed the Service Center in its Dallas NorthPark store and laid off all the technical staff there       (Hp 520 battery)         .

Dell Partner Program

In late 2007, Dell Inc. announced that it planned to expand its program to value-added resellers (VARs), giving it the official name of "Dell Partner Direct" and a new Website  .  Dell Inc. realized  that this program, once a small factor in Dell Inc. sales, had become a growing sector of its business and it desired to leverage this growing outlet for its products. It promised VARs who joined this program increased discounts on product and the ability to use the Dell name and logo in their marketing efforts. ConnectU became an early member  of the program         (SONY VGP-BPS13 Battery)          .

The overall success of this program — as a new development for Dell Inc. — remains unclear.[citation needed]

Retail in the United States

In the early 1990s, Dell also sold its products through Best Buy, Costco and Sam's Club stores in the United States. Dell stopped this practice in 1994, citing low profit-margins on the business. In 2003, Dell briefly sold products in Sears stores in the U.S. In 2007, Dell started shipping its products to major retailers in the U.S. once again, starting with Sam's Club and Wal-Mart. Staples, the largest office-supply retailer in the U.S., and Best Buy, the largest electronics retailer in the U.S., became Dell retail partners later that same year       (SONY VAIO VGN-FZ Battery)       .

Retail around the World

As of the end of February 2008, Dell products shipped to one of the largest office-supply retailers in Canada, Staples Business Depot. In April 2008, Future Shop and Best Buy began carrying a subset of Dell products, such as certain desktops, laptops, printers, and monitors        (Dell RM791 battery)         .

Since some shoppers in certain markets show reluctance to purchase technological products through the phone or the Internet, Dell has looked into opening retail operations in some countries in Central Europe and Russia. In April 2007, Dell opened a retail store in Budapest. In October of the same year, Dell opened a retail store in Moscow         (Toshiba Portege R200 Battery) .

In the UK, HMV's flagship Trocadero store has sold Dell XPS PCs since December 2007. From January 2008 the UK stores of DSGi have sold Dell products (in particular, through Currys and PC World stores). As of 2008, the large supermarket-chain Tesco has sold Dell laptops and desktops in outlets throughout the UK          (Toshiba Satellite M60 battery)              .

In May 2008, Dell reached an agreement with office supply chain, Officeworks (part of Coles Group), to stock a few modified models in the Inspiron desktop and notebook range. These models have slightly different model numbers, but almost replicate the ones available from the Dell Store. Dell continued its retail push in the Australian market with its partnership with Harris Technology (another part of Coles Group) in November of the same year        (Dell Studio 1555 Battery)         .

In addition, Dell expanded its retail distributions in Australia through an agreement with discount electrical retailer, The Good Guys, known for "Slashing Prices". Dell agreed to distribute a variety of makes of both desktops and notebooks, including Studio and XPS systems in late 2008. Dell and Dick Smith Electronics (owned by Woolworths Limited) reached an agreement to expand within Dick Smith's 400 stores throughout Australia and New Zealand in May 2009 (1 year since Officeworks — owned by Coles Group — reached a deal)              (Dell Vostro 1400 Battery)       .

The retailer has agreed to distribute a variety of Inspiron and Studio notebooks, with minimal Studio desktops from the Dell range. As of 2009, Dell continues to run and operate its various kiosks in 18 shopping centres throughout Australia. On 31 March 2010 Dell announced to Australian Kiosk employees that they were shutting down the Australian/New Zealand Dell kiosk program        (

Dell Vostro 1500 Battery)             .

Education K12 Market

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Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (August 2010)

There have been many different definitions to the "Intelligent Classroom" over the last 10 years. Some of the definitions are as vague as putting an interactive white board and a projector in the room. Others are more detailed and include specific content           (Toshiba Satellite Pro M50 Battery)      .

Dell Corporation has been a leader for years and has had several different versions of the “Intelligent Classroom”. The most current definition is: “through its ability to stimulate learning on multiple levels, technology can enhance the classroom experience for both teachers and student”.

Other corporations and products have included other definitions. One of these includes: “The most important part of the Intelligent Classroom is the ...Students, Teacher, and the Educational Interaction”. This view stresses the importance of the educational interaction rather than just products          (Dell Vostro 1510 Battery)      .

Typical technology used in an Intelligent Classroom would include a projector, computer, sound, student response systems, video distribution, and IP TV. All of these products would have one goal, and that is to improve the learning experience for the students. If implemented correctly, Media Rich Curriculum (MRC) is now the center piece of the classroom rather than the technology        (Dell Latitude XT2 Tablet PC Battery)     .

Video Distribution on a local area network requires these key features: A properly designed network and video distribution equipment. A general guideline can be followed if questions are brought up regarding the ability of a specific network to support video distribution: "If the network can support VoiP (Voice Over IP) the network should support video distribution." While this is a general statement, it does help educators set a guideline for implementing MRC on a network going to a classroom        (Dell Vostro A90 Battery)        .


Dell's major competitors include Apple, Hewlett-Packard (HP), Acer, Toshiba, Gateway, Sony, Asus, Lenovo, IBM, Samsung, and Sun Microsystems. Dell and its subsidiary, Alienware, compete in the enthusiast market against AVADirect, Falcon Northwest, VoodooPC (a subsidiary of HP), and other manufacturers. In the second quarter of 2006 Dell had between 18% and 19% share of the worldwide personal computer market, compared to HP with roughly 15%       ( HP Pavilion DV7 Battery).

In late 2006, Dell lost its lead in the PC-business to Hewlett-Packard. Both Gartner and IDC estimated that in the third quarter of 2006, HP shipped more units worldwide than did Dell. Dell's 3.6% growth paled in comparison to HP's 15% growth during the same period. The problem got worse in the fourth quarter, when Gartner estimated that Dell PC shipments declined 8.9% (versus HP's 23.9% growth). As a result, at the end of 2006 Dell's overall PC market-share stood at 13.9% (versus HP's 17.4%)      (Toshiba Satellite Pro M10 Battery).

IDC reported that Dell lost more server market share than any of the top four competitors in that arena. IDC's Q4 2006 estimates show Dell's share of the server market at 8.1%, down from 9.5% in the previous year. This represents a 8.8% loss year-over-year, primarily to competitors EMC and IBM        (Dell Inspiron 300M Battery)       .

Partnership with EMC

The Dell/EMC brand applies solely to products that result from Dell's partnership with EMC Corporation.[citation needed] In some cases Dell and EMC jointly design such products; other cases involve EMC products for which Dell will provide support — generally midrange storage systems, such as fibre channel and iSCSI storage area networks. The relationship also promotes and sells OEM versions of backup, recovery, replication and archiving software           (Dell Latitude D610 Battery).

On December 9, 2008, Dell and EMC announced the multi-year extension, through 2013, of their strategic partnership that began in 2001. In addition, Dell plans to expand its product line-up by adding the EMC Celerra NX4 storage system to the portfolio of Dell/EMC family of networked storage systems, as well as partnering on a new line of de-duplication products as part of its TierDisk family of data-storage devices.

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The iPad is a tablet computer designed and developed by Apple. It is particularly marketed as a platform for audio and visual media such as books, periodicals, movies, music, and games, as well as web content. At about 700 grams (25 ounces), its size and weight are between those of most contemporary smartphones and laptop computers. Apple released the iPad in April 2010, and sold 3 million of the devices in 80 days         (Dell XPS M1210 Battery)         .

The iPad runs the same operating system as the earlier iPod Touch and iPhone, albeit a slightly older version. It can run its own applications as well as ones developed for the iPhone. Without modification, it will only run programs approved by Apple and distributed via its online store       (Dell Studio XPS 1340 Battery)         .

Like iPhone and iPod Touch, the iPad is controlled by a multitouch display — a break from most previous tablet computers, which used a pressure-triggered stylus. The iPad uses a Wi-Fi data connection to browse the Internet, load and stream media, and install software. Some models also have a 3G wireless data connection. The device is managed and synced by iTunes on a personal computer via USB cable       (Dell Studio XPS 1640 Battery)        .

Media reaction to the device has generally been neutral or positive, with more positive reaction after the device was launched.


Apple's first tablet computer was the Newton MessagePad 100,  introduced in 1993, which led to the creation of the ARM6 processor core with Acorn Computers. Apple also developed a prototype PowerBook Duo-based tablet, the PenLite, but in order to avoid hurting MessagePad sales did not sell it.  Apple released several more Newton-based PDAs, and discontinued the last, the MessagePad 2100, in 1998     (Dell Vostro 1710 Battery)       .

With the success of the introduction of portable music player iPod in 2001, Apple re-entered the mobile-computing market in 2007 with the iPhone. Smaller than the iPad but featuring a camera and mobile phone, it pioneered the multitouch finger-sensitive touchscreen interface of Apple's mobile operating system—iOS. By late 2009, the iPad's release had been rumored for several years. Mostly referred to as "Apple's tablet", iTablet and iSlate were among the speculated names        (ASUS EEE PC900 battery)       .

The iPad was announced on January 27, 2010 by Steve Jobs at an Apple press conference at the Yerba Buena Center for the Arts in San Francisco.

Jobs later admitted that the iPad was developed before the iPhone. Upon realizing that it would work just as well as a mobile phone, Jobs put development of the iPad on hold and decided to develop the iPhone instead      (Dell RM791 battery)      .


Screen and input

The iPad's touchscreen display is a 25 cm (9.7 in) liquid crystal display (1024 × 768 pixels) with fingerprint-resistant and scratch-resistant glass. Like the iPhone, the iPad is designed to be controlled by bare fingers; normal gloves and styli that prevent electrical conductivity may not be used,  although there are special gloves and styli designed for this use     (Sony VGP-BPS13 battery)         .

The display responds to two other sensors: an ambient light sensor to adjust screen brightness and a 3-axis accelerometer to sense iPad orientation and switch between portrait and landscape modes. Unlike the iPhone and iPod touch built-in applications, which work in three orientations (portrait, landscape-left and landscape-right), the iPad built-in applications support screen rotation in all four orientations (the three aforementioned ones along with upside-down), meaning that the device has no intrinsic "native" orientation; only the relative position of the home button changes      (sony vgp-bpl9 battery)      .

The iPad has a switch to lock out the screen rotation function (reportedly to prevent unintended rotation when the user is lying down).  There are a total of four physical switches, including a home button below the display that returns the user to the main menu, and three plastic physical switches on the sides: wake/sleep and volume up/down, along with the screen rotation lock.

Ars Technica noted the similarity between the iPad and Star Trek's fictional PADD tablet computer, both in name and functionality        (Sony VGP-BPL11 battery)       .


Steve Jobs, Apple CEO, introducing the iPad

The iPad can use Wi-Fi network trilateration from Skyhook Wireless to provide location information to applications such as Google Maps. The 3G model contains A-GPS to allow its position to be calculated with GPS or relative to nearby cellphone towers; it also has a black plastic accent on the back side to improve 3G radio sensitivity        (Sony VGP-BPL15 battery)         .

For wired connectivity, the iPad has a dock connector; it lacks the Ethernet and USB ports of larger computers.

Audio and output

Back of the iPad

The iPad has two internal speakers that push mono sound through two small sealed channels to the three audio ports carved into the bottom-right of the unit. A volume switch is on the right side of the unit    (Dell Inspiron E1505 battery )      .

A 3.5-mm TRS connector audio-out jack on the top-left corner of the device provides stereo sound for headphones with or without microphones and/or volume controls. The iPad also contains a microphone that can be used for voice recording.

The built-in Bluetooth 2.1 + EDR interface allows wireless headphones and keyboards to be used with the iPad. However, the iOS does not currently support file transfer via Bluetooth. iPad also features 1024 x 768 VGA video output for connecting an external display or television      (Dell Latitude E6400 battery)        .

Power and battery

iPad in the iPad Keyboard Dock

The iPad uses an internal rechargeable lithium-ion polymer battery. The batteries are made in Taiwan by Simplo Technology, which makes 60% of them, and Dynapack International Technology. The iPad is designed to be charged with a high current (2 amperes) using the included USB 10 W power adapter. While it can be charged by a standard USB port from a computer, these are limited to 500 milliamperes (half an amp)       (HP Pavilion dv6000 Battery)       .

As a result, if the iPad is turned on while being charged with a normal USB computer port, it will charge much more slowly, if at all.

Apple claims that the iPad's battery can provide up to 10 hours of video, 140 hours of audio playback, or one month on standby. Like any battery technology, the iPad's LiPo battery loses capacity over time, but is not designed to be user-replaceable. In a program similar to the battery-replacement program for the iPod and the original iPhone, Apple will replace an iPad that does not hold an electrical charge with a refurbished iPad for a fee of US$99 (plus $6.95 shipping)        (Hp Pavilion dv3-1000 battery)      .

Storage and SIM

The iPad was released with three options for internal storage size: a 16, 32, or 64 GB flash drive. All data is stored on the flash drive and there is no option to expand storage. Apple sells a camera connection kit with an SD card reader, but it can only be used to transfer photos and videos     (Dell Precision M70 Battery)         .

The side of the Wi-Fi + 3G model has a micro-SIM slot (not mini-SIM). Unlike the iPhone, which is usually sold locked to specific carriers, the 3G iPad is sold unlocked and can be used with any compatible GSM carrier.  Japan is the exception to this, where the iPad 3G is locked to Softbank. In the U.S., data network access via T-Mobile's network is limited to slower EDGE cellular speeds because T-Mobile's 3G Network uses different frequencies        (Acer Aspire One battery)    .

Optional accessories

The iPad in its case

Apple offers several iPad accessories, including:

iPad Keyboard Dock with hardware keyboard, 30-pin connector, and audio jack

iPad Case which can be used to stand the iPad in various positions

iPad Dock with 30-pin connector and audio jack    (Hp 520 battery)

iPad Dock Connector to VGA Adapter for external monitor or projector

iPad Camera Connection Kit including a USB Type A connector adapter and an SD card reader, for transferring photos and videos

iPad 10W USB Power Adapter with 2 A output (10 W)       (Toshiba Satellite L305 Battery)

Technical specifications

Model       Wi-Fi         Wi-Fi + 3G

Announcement date        January 27, 2010

Release date   April 3, 2010         April 30, 2010

Display     9.7 inches (25 cm) multitouch display at a resolution of 1024 × 768 pixels with LED backlighting and a fingerprint and scratch resistant coating        (Toshiba Satellite Pro M15 Battery)          .

Processor         1 GHz Apple A4 System on a chip

Storage    Fixed capacity of 16, 32, or 64 GB

Wireless  Wi-Fi (802.11a/b/g/n), Bluetooth 2.1+EDR

No wireless wide-area network interface       3G cellular HSDPA, 2G cellular EDGE

Geolocation     Skyhook Wireless     Assisted GPS, Skyhook Wireless, cellular network

Environmental sensors    Accelerometer, ambient light sensor, magnetometer (for digital compass)

Operating system    iOS 3.2.2 and iOS 4.2 Due November         (Toshiba Satellite M65 battery)

Battery    Built-in lithium-ion polymer battery; (10 hours video,  140 hours audio,  1 month standby )

Weight     680 g (1.5 lb)         730 g (1.6 lb)

Dimensions      242.8 × 189.7 × 13.4 mm (9.56 × 7.47 × 0.53 in)

Mechanical keys      Home, sleep, screen rotation lock (mute switch on iOS4.2, volume       (Toshiba Satellite T4900 Battery)      .


The iPad is assembled by Foxconn, which also manufactures Apple's iPod, iPhone and Mac Mini, in its largest plant in Shenzhen, China.

iSuppli estimated that each iPad 16 GB Wi-Fi version costs Apple US$259.60 to manufacture, a total that excludes research, development, licensing and patent costs. Apple does not disclose the makers of iPad components, but teardown reports and analysis from industry insiders indicate that various parts and their suppliers include       (Toshiba PA3399U-2BRS battery)      :

Apple A4 SoC: Samsung..

NAND flash RAM chips: Toshiba; except Samsung for the 64 GB model..

Touch-screen chips: Broadcom.

Touch panels: Wintek. (Got the job after TPK Touch Solutions was unable to fulfill its orders, delaying the iPad's release from late March to early April. )

Case: Catcher Technologies      (Toshiba Satellite A200 Battery)         .

LCD drivers: Novatek Microelectronics.

Batteries: 60% are made in Taiwan by Simplo Technology, 40% by Dynapack International.

Accelerometer: STMicroelectronics.


Like the iPhone, with which it shares a development environment (iPhone SDK, or software development kit, version 3.2 onwards), the iPad only runs its own software, software downloaded from Apple's App Store, and software written by developers who have paid for a developer's license on registered devices.  The iPad runs almost all third-party iPhone applications, displaying them at iPhone size or enlarging them to fill the iPad's screen       (Toshiba Satellite 1200 Battery)       .

Developers may also create or modify apps to take advantage of the iPad's features. Application developers use iPhone SDK for developing applications for iPad. The iPad has been shipping with a customized iPad-only version of iPhone OS, dubbed v3.2. On September 1, it was announced the iPad will get iOS 4.2 by November 2010      (Toshiba NB100 Battery)       .


The iPad comes with several applications, including Safari, Mail, Photos, Video, YouTube, iPod, iTunes, App Store, iBooks, Maps, Notes, Calendar, Contacts, and Spotlight Search.  Several are improved versions of applications developed for the iPhone.

The iPad syncs with iTunes on a Mac or Windows PC.  Apple ported its iWork suite from the Mac to the iPad, and sells pared down versions of Pages, Numbers, and Keynote apps in the App Store       (Toshiba Satellite M300 Battery)        .

Although the iPad is not designed to replace a mobile phone, a user can use a wired headset or the built-in speaker and microphone and place phone calls over Wi-Fi or 3G using a VoIP application.  The iPad has lots of third party applications available for it; as of September 1, 2010 there were 25000 iPad specific apps on the AppStore         (Dell INSPIRON 1525 battery)      .

Digital rights management

For more details on the digital rights management, see iOS.

The iPad employs DRM intended to lock purchased content - including TV shows, movies, and apps-- to operate only on Apple's platform. Also, the iPad's development model requires anyone creating an app for the iPad to sign a non-disclosure agreement and pay for a developer subscription. Furthermore, critics argue Apple's centralized app approval process and control and lockdown of the platform itself could stifle software innovation       (SONY VAIO VGN-FZ280E Battery)       .

Of particular concern to digital rights advocates is the ability for Apple to remotely disable or delete apps, media, or data on the iPad at will.

Digital rights advocates, including the Free Software Foundation, Electronic Frontier Foundation, and computer engineer and activist Brewster Kahle, have criticized the iPad for its digital rights restrictions. Paul Sweeting, an analyst with GigaOM, is quoted by National Public Radio saying, "With the iPad, you have the anti-Internet in your hands       (SONY VAIO VGN-FZ410 Battery)      .

It offers [the major media companies] the opportunity to essentially re-create the old business model, wherein they are pushing content to you on their terms rather than you going out and finding content, or a search engine discovering content for you." But Sweeting also thinks Apple's limitations make its products feel like living in a safe neighborhood, saying, "Apple is offering you a gated community where there's a guard at the gate, and there's probably maid service, too        (SONY VAIO VGN-FZ160 Battery)       ."

Laura Sydell, the article's author, concludes, "As more consumers have fears about security on the Internet, viruses and malware, they may be happy to opt for Apple's gated community."


For more details on iPad Jailbreaking, see iOS jailbreaking.

Like other iOS Devices, the iPad can be "jailbroken", allowing applications and programs that are not authorized by Apple to run on the device. Once jailbroken, iPad users are able to download many applications previously unavailable through the App Store via unofficial installers such as Cydia, as well as illegally pirated applications      (SONY VAIO VGN-FZ38M Battery)        .

Apple claims jailbreaking voids their factory warranty on the device in the United States.

Books, news, and magazine content

Reading a book on the iPad

Further information: iBookstore

The iPad has an optional iBooks application that can be downloaded from the App Store, which displays books and other ePub-format content downloaded from the iBookstore.  For the iPad launch on April 3, 2010, the iBookstore is available only in the United States   (SONY VAIO VGN-FZ21m Battery)          .

Several major book publishers including Penguin Books, HarperCollins, Simon & Schuster and Macmillan have committed to publishing books for the iPad.

In February 2010, Condé Nast Publications said it would sell iPad subscriptions for its GQ, Vanity Fair and Wired magazines by June.  In April 2010, The New York Times announced it will begin publishing daily on the iPad         (SONY VAIO VGN-FZ18m Battery)  .

Major news organizations, such as The Wall Street Journal, BBC, and Reuters have released iPad applications, to varying degrees of success.


Further information: Apple App Store censorship

Apple's App Store, which provides iPhone and iPad applications, imposes censorship of content, which has become an issue for book publishers and magazines seeking to use the platform. The Guardian described the role of Apple as analogous to that of the distributor WH Smith, a main distributor which for many years imposed content restrictions on British publishers      (SONY VAIO VGN-FZ11m Battery)         .

Pornography on the iPad

Due to the exclusion of porn from the App Store, YouPorn and others changed their video format from Flash to H.264 and HTML5 specifically for the iPad. In an e-mail exchange[78] with Ryan Tate from Valleywag, Steve Jobs claimed that the iPad offers "freedom from porn", leading to many upset replies including Adbustings in Berlin by artist Johannes P. Osterhoff  and in San Francisco during WWDC10        (SONY VAIO VGN-FZ11z Battery)           .


Apple began taking pre-orders for the iPad from U.S. customers on March 12, 2010.  The only major change to the device between its announcement and being available to pre-order was the addition of a rotation lock in place of the mute button. The Wi-Fi version of the iPad went on sale in the United States on April 3, 2010. The Wi-Fi + 3G version was released on April 30       (SONY VAIO VGN-FZ11l Battery)       .

3G service in the United States is provided by AT&T and was initially sold with two prepaid contract-free data plan options: one for unlimited data and the other for 250 MB per month at half the price.  On June 2, 2010, AT&T announced that effective June 7 the unlimited plan would be replaced for new customers with a 2 GB plan at slightly lower cost; existing customers would have the option to keep the unlimited plan      (SONY VAIO VGN-FZ31z Battery)                     .

The plans are activated on the iPad itself and can be canceled at any time.

The iPad was launched in Australia, Canada, France, Germany, Italy, Japan, Spain, Switzerland and the United Kingdom on May 28.  Online pre-orders in those countries began on May 10. Apple released the iPad in Austria, Belgium, Hong Kong, Ireland, Luxembourg, Mexico, Netherlands, New Zealand and Singapore on 23 July 2010       (Dell Studio 1555 Battery)        .

Israel briefly prohibited importation of the iPad because of concerns that its Wi-Fi might interfere with other devices.  On September 17, 2010 the iPad officially launched in China.

The device was initially popular with 300,000 iPads being sold on their first day of availability.  By May 3, 2010 Apple had sold a million iPads,  this was in half the time it took Apple to sell the same number of original iPhones. By May 31, 2010 Apple had sold two million iPads and by June 22, 2010 they had sold 3 million     (Dell Vostro 1720 Battery)          .

The South Korean Minister of Ministry of Culture and Tourism, Yu In-chon was criticized for using an "unapproved" iPad on a public occasion; it is illegal to use an unapproved electronic device in South Korea.


Reaction to the announcement

Media reaction to the iPad announcement was mixed. Walt Mossberg wrote, "It's about the software, stupid", meaning hardware features and build are less important to the iPad's success than software and user interface, his first impressions of which were largely positive. Mossberg also called the price "modest" for a device of its capabilities, and praised the ten-hour battery life    (Dell Vostro 1500 Battery)          .

Others, including PC Advisor and The Sydney Morning Herald, wrote that the iPad would also compete with proliferating netbooks, most of which use Microsoft Windows. The base model's $499 price was lower than pre-release estimates by the tech press, Wall Street analysts, and Apple's competitors, all of whom were expecting a much higher entry price point     (Dell Latitude D830 Battery)   .

Yair Reiner said the iPad will compete against e-book devices such as the Barnes & Noble nook and the Amazon Kindle while offering 70 percent of revenue to publishers, the same arrangement afforded developers on the Apple App Store. Notably, a week before the iPad's expected release, the Amazon Kindle store increased publishers' revenue share to 70 percent as well       (Dell Latitude D620 Battery)             .

Several days after the unveiling, Stephen Fry said people must use the iPad to truly appreciate its purpose and quality and commented that common criticisms of the device fall away after use. Fry noted the iPad's speed and responsiveness, the intuitive interface and the richness and detail of the display. Along with Steve Jobs' statements in the announcement members of the media also said that it established a new class of devices between smartphones and laptops        (SONY VAIO VGN-FZ150E Battery)         .


Reviews of the iPad have been generally favorable. Walt Mossberg of The Wall Street Journal called it a "pretty close" laptop killer.  David Pogue of The New York Times wrote a "dual" review, one part for technology-minded people, and the other part for non-technology-minded people. In the former section, he notes that a laptop offers more features for a cheaper price than the iPad       (Dell Studio 1735 Battery)          .

In his review for the latter audience, however, he claims that if his readers like the concept of the device and can understand what its intended uses are, then they will enjoy using the device. Ed Baig of USA Today bluntly states that the iPad "is a winner". Andy Ihnatko of the Chicago Sun-Times calls the iPad "one of the best computers ever"        Sony VGN-FZ31Z Battery)        .

PC Magazine's Tim Gideon wrote, "you have yourself a winner" that "will undoubtedly be a driving force in shaping the emerging tablet landscape."[112] Michael Arrington of TechCrunch said, "the iPad beats even my most optimistic expectations. This is a new category of device. But it also will replace laptops for many people     (Dell Inspiron 300M Battery)      ."

PC World criticized the iPad's slim file-sharing and printing abilities, and Ars Technica said sharing files with a computer is "without a doubt one of our least favorite parts of the iPad experience."

Reaction to the international launch

On May 28, 2010 the iPad was released in Australia, Canada, Japan as well as several larger European countries. Media reaction to the launch was mixed. The media noted the positive response from fans for the device with thousands of people queued on the first day of sale in a number of these countries       (Dell Studio 1737 battery)     .

The media also praised the quantity of applications, as well as the bookstore and other media applications.  In contrast they criticized the iPad for being a closed system and mentioned that the iPad faces competition from Android based tablets.  With regards to its books application The Independent criticized the iPad for not being as readable in bright light as paper. However they also praised the device for being able to store a large number of different books         (Dell XPS M1530 battery)      .

Omitted features

CNET and Gizmodo listed features that are missing from the iPad that they believe customers expect, including a camera for video chat, Adobe Flash support, a longer and narrower "widescreen" aspect ratio suitable for watching widescreen movies, and the ability to multitask (run more than one application at once), a USB port, HDMI output, and a more flexible wired-data port than the iPod dock connector          (Dell XPS M2010 battery)       .

According to Apple's iOS 4 unveiling and demonstration on April 8, 2010, as well as the Keynote presentation available on their website, multitasking will be available to all iPad users with a software update in the fall of 2010. The Seattle Post-Intelligencer and Gizmodo noted that the iPad will officially support installing software only from the App Store           (Dell Vostro 1000 battery)          .

CNET also criticised the iPad for its apparent lack of wireless sync which other portable devices such as Microsoft's Zune have had for a number of years. The built-in iTunes app is able to download from the Internet as well.

CNN and Wired News defended Apple's omission of a number of features, including support for Adobe Flash, noting that YouTube and Vimeo have switched to H.264 for video streaming         (HP Pavilion dv9000 battery)   .

They also said that " will not matter at all to the target user", as its absence is responsible for "a large part of [the iPad's] ten-hour battery life." Multitasking will be added in the next iPad software update. Of the aspect ratio: "16:9 ratio in [portrait mode] would look oddly tall and skinny ... [4:3 is] a compromise, and a good one." Of the lack of a USB port: "The iPad is meant to be an easy-to-use appliance, not an all-purpose computer. A USB port would mean installing drivers for printers, scanners and anything else you might hook up         (Hp 520 battery)     ."

People have been divided over whether to consider the iPad a personal computer. Forrester Research has argued that the iPad should be considered a form of personal computer in spite of Apple's restrictions on creating and editing files with the iPad.  In contrast PC World have argued that the iPad isn't a personal computer due to it omitting several key features including multitasking and support for Adobe Flash         (SONY VGP-BPS13 Battery)     .

Product name

Like the iPhone, the iPad shares its name with existing products. The most publicized is the Fujitsu iPAD, a mobile multi-functional device sold to retailers to help clerks verify prices, check inventory, and close sales. The Japanese company Fujitsu introduced the iPAD in 2002, and the following year applied for the trademark, but the firm found the mark was already owned by Mag-Tek. Fujitsu's trademark application was listed as "abandoned" in April 2009, and the ownership of the mark is unclear          (SONY VAIO VGN-FZ Battery)        .

Fujitsu consulted attorneys over what, if any, action it might take.  On March 17, 2010 the Fujitsu iPAD U.S. trademark was transferred to Apple.

In the first days after the iPad's announcement, some media and many online commenters criticized the name "iPad", noting its similarity to "pad", the common name for a sanitary napkin.  Shortly after the launch announcement, the hashtag "iTampon" became the number-two trending topic on the social networking site Twitter        (Dell RM791 battery)        .

Available Locations

The iPad was initially only available online at The Apple Store as well as the companys' retail locations. The iPad has become available in retail outlets such as Target and Best Buy.



While the iPad is mostly used by consumers it also has been taken up by business users. Some companies are adopting iPads in their business offices by distributing or making available the iPads to employees. Examples of uses in the workplace include attorneys responding to clients, medical professionals accessing health records during patient exams, and managers approving employee requests            (Toshiba Portege R200 Battery)     .


The iPad has several uses in the classroom , and has been praised as a valuable tool for homeschooling.  Several iPad apps have been developed just for children, like Cat in the Hat, Baby Flashcards, and the Miss Spider apps. Soon after the iPad was released, it was reported that 81% of the top book apps were for children. The iPad has also been called a revolutionary tool to help children with autism learn how to communicate and socialize more easily     (Toshiba Satellite M60 battery)             .

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12 octobre 2010 2 12 /10 /octobre /2010 04:34

PayPal is an e-commerce business allowing payments and money transfers to be made through the Internet. PayPal serves as an electronic alternative to traditional paper methods such as checks and money orders      (Dell XPS M1210 Battery)    .

A PayPal account can be funded with an electronic debit from a bank account or by a credit card. The recipient of a PayPal transfer can either request a check from PayPal, establish their own PayPal deposit account or request a transfer to their bank account. PayPal is an example of a payment intermediary service that facilitates worldwide e-commerce      (Dell Studio XPS 1340 Battery)   .

PayPal performs payment processing for online vendors, auction sites, and other commercial users, for which it charges a fee. It sometimes also charges a transaction fee for receiving money (a percentage of the amount sent plus an additional fixed amount). The fees charged depend on the currency used, the payment option used, the country of the sender, the country of the recipient, the amount sent and the recipient's account type        (Dell Studio XPS 1640 Battery)      .

In addition, eBay purchases made by credit card through PayPal may incur a "foreign transaction fee" if the seller is located in another country, as credit card issuers are automatically informed of the seller's country of origin.

On October 3, 2002, PayPal became a wholly owned subsidiary of eBay      (Dell Vostro 1710 Battery)        .

Its corporate headquarters are in San Jose, California, United States at eBay's North First Street satellite office campus. The company also has significant operations in Omaha, Nebraska; Scottsdale, Arizona; and Austin, Texas in the U.S., Chennai, Dublin, Berlin and Tel-Aviv. As of July 2007, across Europe, PayPal also operates as a Luxembourg-based bank    (ASUS EEE PC900 battery)     .

On March 17, 2010, PayPal entered into an agreement with China UnionPay (CUP), China's bankcard association, to allow Chinese consumers to use PayPal to shop online.[citation needed] PayPal is planning to expand its workforce in Asia to 2,000 by the end of the year 2010        (Dell RM791 battery)        .



The current incarnation of PayPal is the result of a March 2000 merger between Confinity and X.com. Confinity was founded in December 1998 by Max Levchin, Peter Thiel, Luke Nosek, and Ken Howery, initially as a Palm Pilot payments and cryptography company    (Sony VGP-BPS13 battery)        .

X.com was founded by Elon Musk in March 1999, initially as an Internet financial services company. Both Confinity and X.com launched their websites in late 1999. Both companies were located on University Avenue in Palo Alto. Confinity's website was initially focused on reconciling beamed payments from Palm Pilots  with email payments as a feature and X.com's website initially featured financial services with email payments as a feature       (sony vgp-bpl9 battery)       .

At Confinity, many of the initial recruits were alumni of The Stanford Review, also founded by Peter Thiel, and most early engineers hailed from the University of Illinois at Urbana-Champaign, recruited by Max Levchin. On the X.com side, Elon Musk recruited a wide range of technical and business personnel, including many that were critical to the combined company's success, such as Amy Klement, Sal Giambanco, Roelof Botha[9] of Sequoia Capital, Sanjay Bhargava and Jeremy Stoppelman    (Sony VGP-BPL11 battery) .

To block potentially fraudulent access by automated systems, PayPal used a system (see CAPTCHA) of making the user enter numbers from a blurry picture, which they coined the Gausebeck-Levchin test.

eBay watched the rise in volume of its online payments and realized the fit of an online payment system with online auctions. eBay purchased Billpoint in May 1999, prior to the existence of PayPal     (Sony VGP-BPL15 battery)       .

eBay made Billpoint its official payment system, dubbing it "eBay Payments," but cut the functionality of Billpoint by narrowing it to only payments made for eBay auctions. For this reason, PayPal was listed in many more auctions than Billpoint. In February 2000, the PayPal service had an average of approximately 200,000 daily auctions while Billpoint (in beta) had only 4,000 auctions  (Dell Inspiron E1505 battery )      .

By April 2000, more than 1,000,000 auctions promoted the PayPal service.  PayPal was able to turn the corner and become the first dot-com to IPO after the September 11 attacks.

Acquisition by eBay

In October 2002, PayPal was acquired by eBay for $1.5 billion.PayPal had previously been the payment method of choice by more than fifty percent of eBay users, and the service competed with eBay's subsidiary Billpoint, Citibank's c2it, whose service was closed in late 2003, and Yahoo!'s PayDirect, whose service was closed in late 2004      (Dell Latitude E6400 battery)      .

Western Union announced the December 2005 shut down of their BidPay service but subsequently sold it in 2006 to CyberSource Corporation. BidPay subsequently ceased operations on December 31, 2007. Some competitors which offer some of PayPal's services, such as Google Checkout, Wirecard, Moneybookers, 2Checkout.com, CCNow and Kagi, remain in business, despite the fact that eBay now requires everyone on its Australian and United Kingdom sites to offer PayPal         (HP Pavilion dv6000 Battery)         .

Eventually eBay moderated its position, and mandated that sellers on eBay Australia offer PayPal as one of the (but not necessarily the only) payment methods.[19] These accepted payment methods include bank deposit, cheques and money orders, escrow, and credit cards (processed by other than PayPal)        (Hp Pavilion dv3-1000 battery)        .

In January 2008, PayPal agreed to acquire Fraud Sciences, a privately-held Israeli start-up company with expertise in online risk tools, for $169 million, in order to enhance eBay and PayPal's proprietary fraud management systems and accelerate the development of improved fraud detection tools.  In November 2008, the company acquired Bill Me Later, an online payments company offering transactional credit at over 1000 online merchants in the US       (Dell Precision M70 Battery)       .

PayPal's total payment volume, the total value of transactions, was US$ 60 billion in 2008, an increase of 27 percent over the previous year,  and US$ 71 billion in 2009, an increase of 19 percent over the previous year.  The company continues to focus on international growth and growth of its Merchant Services division, providing e-payments for retailers off eBay      (Acer Aspire One battery)          .

Business today

Currently, PayPal operates in 190 markets, and it manages over 223 million accounts, more than 73 million of them active. PayPal allows customers to send, receive, and hold funds in 19 currencies worldwide. These currencies are the Australian dollar, Brazilian real, Canadian dollar, Chinese renminbi yuan (only available for some Chinese accounts, see below), Euro, pound sterling, Japanese yen, Czech koruna, Danish krone, Hong Kong dollar, Hungarian forint, Israeli new sheqel, Mexican peso, New Zealand dollar, Norwegian krone, Polish zloty, Singapore dollar, Swedish krona, Swiss franc and U.S. dollar        (Hp 520 battery)       .

PayPal operates locally in 13 countries.

Residents in 194 markets can use PayPal in their local markets to send money online.

PayPal revenues for Q1 2009 were $643 million, up 11 percent year over year. 42 percent of revenues in q1 2009 were from international markets. PayPal's Total Payment Volume (TPV), the total value of transactions in Q1 2009 was nearly $16 billion, up 10 percent year over year       (Toshiba Satellite L305 Battery)        .

In 2008, PayPal's TPV off eBay exceeded volume on eBay for the first time. PayPal's Total Payment Volume in 2008 was $60 billion representing nearly 9 percent of global e-commerce and 15 percent of US e-commerce.

At an analyst day on March 11, 2009, eBay CEO, John Donahoe announced that PayPal could be a larger driver of revenue than the eBay marketplaces business      (Toshiba Satellite Pro M15 Battery)       .

RIM announced that PayPal will be the only payment mechanism for its Blackberry App World, which launched on April 1, 2009.[28]

In November 2009 PayPal opened its platform, allowing other services to get access to its code and to use its infrastructure in order to enable peer-to-peer online transactions.

Paypal Operations Center and main office outside Omaha, NE    (Toshiba Satellite M65 battery)

Although PayPal's corporate headquarters are located in San Jose, PayPal's operations center is located near Omaha, Nebraska, where the company employs more than 2,000 people as of 2007.  PayPal's European headquarters are in Luxembourg and international headquarters in Singapore. The company also recently opened a technology center in Scottsdale, Arizona, and Chennai India        (Toshiba Satellite T4900 Battery)       .

Local restrictions


In China PayPal offers two kinds of accounts:

PayPal.com accounts, for sending and receiving money to/from other PayPal.com accounts. All non-Chinese accounts are PayPal.com accounts, so these accounts may be used to send money internationally.

PayPal.cn accounts, for sending and receiving money to and from other PayPal.cn accounts.

It is impossible to send money between PayPal.cn accounts and PayPal.com accounts, so PayPal.cn accounts are effectively unable to make international payments. For PayPal.cn, the only supported currency is the renminbi        (Toshiba PA3399U-2BRS battery)  .


In late March 2010, new Japanese regulations forced PayPal to suspend the ability of Japanese individuals to pay money to other individuals      (Toshiba Satellite A200 Battery)     .


As of mid July 2010, users in Taiwan have noticed that the "Personal" tab for sending money has been omitted without notice. There is no longer an option to send personal payments, thus forcing all recipients to pay a fee  (Toshiba Satellite 1200 Battery)   .


PayPal's innovation environment, Paypal-Labs.com,  hosts several outreach and experimental projects such as the storefront application,  the MySpace and Facebook donation widgets, and the PayPal blog        (Toshiba NB100 Battery)        .

Bank status

In the United States, PayPal is licensed as a money transmitter on a state-by-state basis.  PayPal is not classified as a bank in the United States, though the company is subject to some of the rules and regulations governing the financial industry including Regulation E consumer protections and the USA PATRIOT Act      (Toshiba Satellite M300 Battery)      .

Commencing 2 July 2007, as PayPal (Europe) S.à r.l. & Cie, S.C.A., PayPal moved its European operations from the UK to Luxembourg. As a Luxembourg entity, it is since regulated as a bank by the Commission de Surveillance du Secteur Financier (CSSF) and provides PayPal service throughout the European Union       (Dell INSPIRON 1525 battery)           .

Safety and protection policies

The PayPal Buyer Protection Policy states that the customer may file a buyer complaint within 45 days if he did not receive an item or if the item they purchased was significantly not as described. If the buyer used a credit card, he might get a refund via chargeback from his credit-card company    (SONY VAIO VGN-FZ280E Battery)       .

According to PayPal, it protects sellers in a limited fashion via the Seller Protection Policy. In general the Seller Protection Policy is intended to protect the seller from certain kinds of chargebacks or complaints if seller meets certain conditions including proof of delivery to the buyer. PayPal states the Seller Protection Policy is "designed to protect sellers against claims by buyers of unauthorized payments and against claims of non-receipt of any merchandise"         (SONY VAIO VGN-FZ410 Battery)      .

The policy includes a list of "Exclusions" which itself includes "Intangible goods", "Claims for receipt of goods 'not as described'" and "Total reversals over the annual limit". There are also other restrictions in terms of the sale itself, the payment method and the destination country the item is shipped to (simply having a tracking mechanism is not sufficient to guarantee the Seller Protection Policy is in effect         (SONY VAIO VGN-FZ160 Battery)     .



Security key

In early 2006, PayPal introduced an optional security key as an additional precaution against fraud. A user account tied to a security key has a modified login process: the account holder enters their login ID and password, as normal, but is then prompted to press the button on the security key and enter the six-digit number generated by it      (SONY VAIO VGN-FZ38M Battery)        .

This two-factor authentication is intended to make account compromise by a malicious third party without access to the physical security key difficult, although it does not prevent so-called Man in the Browser (MITB) attacks. However, the user (or malicious third party) can alternatively authenticate by providing the credit card or bank account number listed on their account. Thus, the PayPal's implementation does not offer the security of true two-factor authentication      (SONY VAIO VGN-FZ21m Battery)    .

The key currently costs US$5.00 for all users with no ongoing fees.[40] The option of using a security key with one's account is currently available only to users registered in Australia, Germany, Canada, the United Kingdom and the United States.


It is also possible to use a mobile phone to receive an MTAN (Mobile Transaction Authentication Number) via SMS,. Like all security measures, there have been reports of vulnerabilities to older mobile handsets       (SONY VAIO VGN-FZ18m Battery)    .


In Europe, PayPal is registered as a bank in Luxembourg under the legal name PayPal (Europe) Sàrl et Cie SCA, a company regulated centrally by the Luxembourg bank authority, the Commission de Surveillance du Secteur Financier (CSSF)(note that all of the company's European accounts were transferred to the PayPal's bank in Luxembourg on July 2, 2007     (SONY VAIO VGN-FZ11m Battery)        .

Prior to this move, PayPal had been registered in the UK as Paypal (Europe) Ltd, an entity which was licensed as an Electronic Money Issuer with the UK's Financial Services Authority (FSA) from 2004. This ceased in 2007, when the company moved to Luxembourg.

In the US, although PayPal has an extensive User Agreement,  PayPal is not directly regulated by the U.S. federal government, because it serves as a payment intermediary      (SONY VAIO VGN-FZ11z Battery)            .

The law is unclear as to whether PayPal is a bank, narrow bank, money services business or money transmitter. PayPal could also be subject to state regulation, but state laws vary, as do their definitions of banks, narrow banks, money services businesses and money transmitters     (SONY VAIO VGN-FZ11l Battery)       .

The most analogous regulatory source of law for PayPal transactions comes from P2P payments using credit and debit cards. Ordinarily, a credit card transaction, specifically the relationship between the issuing bank and the cardholder, is governed by the Truth in Lending Act (TILA) 15 U.S.C. §§ 1601-1667f as implemented by Regulation Z, 12 C.F.R. pt. 226, (TILA/Z). TILA/Z requires specific procedures for billing errors, dispute resolution and limits cardholder liability for unauthorized charges      (SONY VAIO VGN-FZ31z Battery)             .

Similarly, the legal relationship between a debit cardholder and the issuing bank is regulated by the Electronic Funds Transfer Act (EFTA) 15 U.S.C. §§ 1693-1693r, as implemented by Regulation E, 12 C.F.R. pr. 205, (EFTA/E). EFTA/E is directed at consumer protection and provides strict error resolution procedures. However, because PayPal is a payment intermediary and not otherwise regulated directly, TILA/Z and EFTA/E do not operate exactly as written once the credit/debit card transaction occurs via PayPal       (Dell Studio 1555 Battery)         .

Basically, unless a PayPal transaction is funded with a credit card, the consumer has no recourse in the event of fraud by the seller.

In India, as of January 27, 2010, PayPal has no cross-border money transfer authorization. In The New York Times article "India’s Central Bank Stops Some PayPal Services", Reserve Bank of India spokesman Alpana Killawalla stated: "Providers of cross-border money transfer service need prior authorization from the Reserve Bank under the Payment and Settlement Systems Act, PayPal does not have our authorization        (Dell Vostro 1720 Battery)        ."

PayPal is not listed in the "Certificates of Authorisation issued by the Reserve Bank of India under the Payment and Settlement Systems Act, 2007 for Setting up and Operating Payment System in India".


Money transfers via PayPal create an inherent risk of fraud due to the impersonal nature of internet commerce and the gap in regulatory treatment of PayPal transactions. The existing fraud protection regulations, EFTA/E and TILA/Z, do not apply to P2P account holders as they do debit/credit card transactions outside of a P2P payment service       (Dell Vostro 1500 Battery)      .

If an unauthorized third party obtains and uses someone's PayPal login information and completes a transaction using the accountholder's debit or credit card, EFTA/E and TILA/Z make PayPal responsible for the breach. There are, of course, fact specific exceptions to this rule. One is if funds are illicitly withdrawn from a PayPal deposit account. In that situation, neither PayPal nor the bank is required to return the funds, because the agreement between a consumer and PayPal makes those types of transactions authorized        (Dell Latitude D830 Battery)       .

PayPal account holders' private information is marginally protected under one federal law. Since PayPal is a financial institution under the Gramm-Leach-Bliley Act (GLB), it cannot disclose its account holders' non-public personal information to third parties unless account holders opt in to those disclosures      (Dell Latitude D620 Battery)         .

If an account is subject to fraud or unauthorized use, PayPal puts the "Limited Access" designation on the account. At this point, the account holder must:

Log in

Reset their password

Develop a set of security questions (based on the hypothetical and not fact — e.g. "What is your favorite ice cream?" not "What is your mother's maiden name?")

Verify location by phone or by mail     (Dell XPS M1210 Battery)       .


PayPal presents anti-phishing advice on their website  for identifying and reporting phishing. PayPal encourages consumers to report all phishing emails to them     (Dell Studio XPS 1340 Battery)        .

Criticism and limitations

This article's Criticism or Controversy section(s) may mean the article does not present a neutral point of view of the subject. It may be better to integrate the material in those sections into the article as a whole       (Dell Vostro 1015 Battery)        . (May 2009)

See also: Criticism of eBay

The current PayPal user agreement is 25 pages long. If one buys an item from a PayPal merchant, one is agreeing to an additional layer of arbitration beyond the merchant himself. Thus even if the merchant has acted improperly, PayPal has not violated their own policy until the user has gone through an extra arbitration process with PayPal. Only when PayPal fails to arbitrate according to their 25-page user agreement can the user go on to the normal dispute resolution with his credit card issuer        (Dell Vostro A90 Battery) .

In other words, he is making a contract with PayPal under the 25-page policy, not the simple 1-page policy one would expect from any reputable merchant.

In September 2005, Richard Kyanka, owner of the website Something Awful, set up an account to collect donations for Hurricane Katrina to be given to the Red Cross        (Dell Vostro A860 Battery)       .

Owing to the high rate at which donations were made, the account was automatically frozen, and Kyanka criticized the time and difficulty involved in getting PayPal's customer service to unfreeze the account. In response to the concerns of Something Awful members over the charity used by PayPal, United Way, Kyanka finally opted to have the money refunded to the donors so that they could donate directly to their charities of choice, though PayPal did not refund exchange and handling fees for international donors (Dell Vostro 2510 Battery)      .

In March 2008, Australian current affairs show Today Tonight aired a segment criticising PayPal, with regard to safety, freezing accounts and customer service.

Several PayPal gripe sites have been created complaining of problems such as the freezing of accounts of eCommerce stores if they experience rapid growth, preventing them from being able to pay suppliers and fulfill orders      (IBM ThinkPad T60 battery)      .

One such site, Paypalsucks.com,[2] ranked third on a Forbes Magazine listing of "Top Corporate Hate Web Sites" in 2005 based on "hostility" and "entertainment value" of web forum postings and other criteria.

In June 2008, the Australian Competition and Consumer Commission found that, "The evidence available does not support the view that PayPal is the most secure method of payment, or offers the best service for all transactions     (HP Pavilion dv9000 battery)   ."

In February 2010, Paypal stopped or reversed all "personal" transactions in or out of India without prior notice. Funds already transferred and transactions that had previously been "completed" were reversed leaving many vendor accounts over-drafted. Companies, contractors and service providers throughout India were left in debt to Paypal for services they had already provided when Paypal, without warning or consent, returned funds vendors had already received and withdrawn      (Dell Vostro 1000 battery) .

In spite of its international reach, Paypal has limited functionalites for multi-country users, most notably the impossibility to have bank accounts in several countries, or to have a shipping address in a different country than one's bank account / credit card.

In March 2010, Paypal froze donations to Cryptome, seizing over $5300 of in-transit donations  (Dell XPS M2010 battery)   .

PayPal refused to inform Cryptome of the reason for this action, claiming that to disclose why the donations had been confiscated would violate Cryptome's own privacy.  A week later, PayPal offered an apology, which was rejected by Cryptome founder John Young as "insulting and unacceptable"    (Toshiba Tecra 8000 Battery)      .

In September 2010, PayPal froze the account of Markus Persson, developer of the independent video game Minecraft. His account contained around €600,000.

Also in September 2010, PayPal froze the account of the open-source revision control software TortoiseSVN. The lead developer compared the situation to a car shop that "decides not to do business with you anymore. ... But then the shop owner tells you that they keep your car for half a year first because that's their policy      (Toshiba Portege 2000 Battery)     ."


This article may need to be updated. Please update this article to reflect recent events or newly available information, and remove this template when finished. Please see the talk page for more information. (July 2010)

In 2002, CertCo filed a suit against PayPal claiming patent infringement concerning the use of distributed computing systems that process micropayments, or small cash amounts. In April 2002, CertCo dropped the suit and stated that they had come to a settlement involving, "a non-consequential payment and mutual releases      (Toshiba Satellite 3005 Battery)         ."

In March 2002, two PayPal account holders separately sued the company for alleged violations of the Electronic Funds Transfer Act (EFTA) and California law. Most of the allegations concerned PayPal's dispute resolution procedures. The two lawsuits were merged into one class action lawsuit (In re: PayPal litigation)        (HP Pavilion DV5 Battery)        .

An informal settlement was reached in November 2003, and a formal settlement was signed on June 11, 2004. The settlement requires that PayPal change its business practices (including changing its dispute resolution procedures to make them EFTA-compliant), as well as making a US$9.25 million payment to members of the class. PayPal denied any wrongdoing     (Dell XPS M1530 battery)         .

In May 2002, Tumbleweed Communications filed a lawsuit against PayPal (and later expanded it to include eBay) claiming that PayPal had violated its patents for sending personalized links through e-mail, which PayPal uses to alert its customers about financial transactions. In January 2004, the two parties came to an agreement, but didn't disclose the financial terms of their licensing agreement      (Toshiba Portege R200 Battery)     .

In June 2003, Stamps.com filed a lawsuit against PayPal and eBay claiming breach of contract, breach of the implied covenants of good faith and fair dealing, and interference with contract, among other claims. In a 2002 license agreement, Stamps.com and PayPal agreed that Stamps.com technology would be made available to allow PayPal users to buy and print postage online from their PayPal accounts       (Toshiba Satellite A85 Battery)    .

Stamps.com claimed that PayPal did not live up to its contractual obligations and accused eBay of interfering with PayPal and Stamps.com's agreement, hence Stamp.com's reasoning for including eBay in the suit.

In August 2002, Craig Comb and two others filed a class action against PayPal in, Craig Comb, et al. v. PayPal, Inc.. They sued, alleging illegal misappropriation of customer accounts and detailed ghastly customer service experiences          (Sony VAIO VGN-G218N/B Battery)   .

Allegations included freezing deposited funds for up to 180 days until disputes are resolved by PayPal, and forcing customers to arbitrate their disputes under the American Arbitration Association's guidelines (a costly procedure). The court stated that "the User Agreement and arbitration clause are substantively unconscionable under California law," noting their unjustifiable one-sidedness and explicit prohibition of class actions produces results that "shock the conscience" and indicate PayPal was "attempting to insulate itself contractually from any meaningful challenge to its alleged practices" and ruled against PayPal       (Toshiba Tecra R10-S4401 Battery)          .

In September 2003, PayPal filed suit against Bank One Corporation for patent infringement. PayPal claimed that Bank One's online bill-payment system was an infringement against PayPal's online bill-payment patent, issued in 1998. PayPal filed the suit after a warning to the bank's lawyers in February went unheeded    (Dell Vostro 1400 Battery)        .

In November 2003, AT&T filed suit against eBay and PayPal claiming that their payment systems infringed an AT&T patent, filed in 1991 and granted in 1994.

In March 2004, PayPal and New York state's Attorney General, Eliot Spitzer, came to an agreement to require PayPal to disclose clients' rights and liabilities more accurately and to pay $150,000 to the state of New York for penalties and the costs of the investigation        (Toshiba Satellite P15 Battery)    .

In April 2007, one of two anti-trust lawsuits was filed against eBay/PayPal by Michael Malone of Texas.  This suit claims that the monopolistic relationship between eBay and PayPal violates United States anti-trust laws            (Toshiba Satellite M60 battery)   .

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11 octobre 2010 1 11 /10 /octobre /2010 04:07


A mouse typically controls the motion of a cursor in two dimensions in a graphical user interface (GUI). Clicking or hovering (stopping movement while the cursor is within the bounds of an area) can select files, programs or actions from a list of names, or (in graphical interfaces) through small images called "icons" and other elements       (Dell XPS M1210 Battery)       .

For example, a text file might be represented by a picture of a paper notebook, and clicking while the cursor hovers this icon might cause a text editing program to open the file in a window      .

Users can also employ mice gesturally; meaning that a stylized motion of the mouse cursor itself, called a "gesture", can issue a command or map to a specific action. For example, in a drawing program, moving the mouse in a rapid "x" motion over a shape might delete the shape      (Dell Studio XPS 1340 Battery)         .

Gestural interfaces occur more rarely than plain pointing-and-clicking; and people often find them more difficult to use, because they require finer motor-control from the user. However, a few gestural conventions have become widespread, including the drag-and-drop gesture, in which     (Dell Studio XPS 1640 Battery)         :

The user presses the mouse button while the mouse cursor hovers over an interface object

The user moves the cursor to a different location while holding the button down

The user releases the mouse button

For example, a user might drag-and-drop a picture representing a file onto a picture of a trash can, thus instructing the system to delete the file        (Dell Vostro 1710 Battery)         .

Other uses of the mouse's input occur commonly in special application-domains. In interactive three-dimensional graphics, the mouse's motion often translates directly into changes in the virtual camera's orientation. For example, in the first-person shooter genre of games (see below), players usually employ the mouse to control the direction in which the virtual player's "head" faces    (ASUS EEE PC900 battery)           :

moving the mouse up will cause the player to look up, revealing the view above the player's head. A related function makes an image of an object rotate, so that all sides can be examined.

When mice have more than one button, software may assign different functions to each button       (Dell RM791 battery)     .

Often, the primary (leftmost in a right-handed configuration) button on the mouse will select items, and the secondary (rightmost in a right-handed) button will bring up a menu of alternative actions applicable to that item. For example, on platforms with more than one button, the Mozilla web browser will follow a link in response to a primary button click, will bring up a contextual menu of alternative actions for that link in response to a secondary-button click, and will often open the link in a new tab or window in response to a click with the tertiary (middle) mouse button    (Sony VGP-BPS13 battery)        .

Different ways of operating the mouse cause specific things to happen in the GUI:

Click: pressing and releasing a button.

(left) Single-click: clicking the main button.

(left) Double-click: clicking the button two times in quick succession counts as a different gesture than two separate single clicks.

(left) Triple-click: clicking the button three times in quick succession    (sony vgp-bpl9 battery)         .

Right-click: clicking the secondary button.

Middle-click: clicking the ternary button.

Drag: pressing and holding a button, then moving the mouse without releasing. (Use the command "drag with the right mouse button" instead of just "drag" when you instruct a user to drag an object while holding the right mouse button down instead of the more commonly used left mouse button       (Sony VGP-BPL11 battery)        .

Button chording (a.k.a. Rocker navigation).

Combination of right-click then left-click.

Combination of left-click then right-click or keyboard letter.

Combination of left or right-click and the mouse wheel         (Sony VGP-BPL15 battery)      .

Clicking while holding down a modifier key.

Standard semantic gestures include :



Menu traversal      (Dell Inspiron E1505 battery )

Drag and drop


Goal crossing

Multiple-mouse systems

Some systems allow two or more mice to be used at once as input devices. 16-bit era home computers such as the Amiga used this to allow computer games with two players interacting on the same computer. The same idea is sometimes used in collaborative software, e.g. to simulate a whiteboard that multiple users can draw on without passing a single mouse around        (Dell Latitude E6400 battery)           .

Microsoft Windows, since Windows 98, has supported multiple simultaneous pointing devices. Because Windows only provides a single screen cursor, using more than one device at the same time generally results in seemingly random movements of the cursor. However, the advantage of this support lies not in simultaneous use, but in simultaneous availability for alternate use   (HP Pavilion dv6000 Battery)         :

for example, a laptop user editing a complex document might use a handheld mouse for drawing andmanipulation of graphics, but when editing a section of text, use a built-in trackpad to allow movement of the cursor while keeping his hands on the keyboard. Windows' multiple-device support means that the second device is available for use without having to disconnect or disable the first   (Hp Pavilion dv3-1000 battery)           .

As of 2009, Linux distributions and other operating systems that use X.Org, such as OpenSolaris and FreeBSD, support unlimited numbers of cursors and keyboards through Multi-Pointer X.

There have also been propositions of having a single operator use two mice simultaneously as a more sophisticated means of controlling various graphics and multimedia applications       (Dell Precision M70 Battery)         .


Main article: mouse button

Mouse buttons are microswitches which can be pressed ("clicked") in order to select or interact with an element of a graphical user interface.

The three-button scrollmouse has become the most commonly available design         (Acer Aspire One battery)       .

As of 2007 (and roughly since the late 1990s), users most commonly employ the second button to invoke a contextual menu in the computer's software user interface, which contains options specifically tailored to the interface element over which the mouse cursor currently sits  . By default, the primary mouse button sits located on the left-hand side of the mouse, for the benefit of right-handed users; left-handed users can usually reverse this configuration via software      (Hp 520 battery)         .

Mouse speed

The computer industry often measures mouse sensitivity in terms of counts per inch (CPI), commonly expressed less correctly as dots per inch (DPI) – the number of steps the mouse will report when it moves one inch. In early mice, this specification was called pulses per inch (ppi)        (Toshiba Satellite L305 Battery)         .

If the default mouse-tracking condition involves moving the cursor by one screen-pixel or dot on-screen per reported step, then the CPI does equate to DPI: dots of cursor motion per inch of mouse motion. The CPI or DPI as reported by manufacturers depends on how they make the mouse; the higher the CPI, the faster the cursor moves with mouse movement           (Toshiba Satellite Pro M15 Battery)         .

However, software can adjust the mouse sensitivity, making the cursor move faster or slower than its CPI. Current software can change the speed of the cursor dynamically, taking into account the mouse's absolute speed and the movement from the last stop-point. In most software[specify] this setting is named "speed", referring to "cursor precision"         (Toshiba Satellite M65 battery)        .

However, some software[specify] names this setting "acceleration", but this term is in fact incorrect. The mouse acceleration, in the majority of mouse software, refers to the setting allowing the user to modify the cursor acceleration: the change in speed of the cursor over time while the mouse movement is constant       (Toshiba Satellite T4900 Battery)       .

For simple software, when the mouse starts to move, the software will count the number of "counts" received from the mouse and will move the cursor across the screen by that number of pixels (or multiplied by a rate factor, typically less than 1). The cursor will move slowly on the screen, having a good precision        (Toshiba PA3399U-2BRS battery)        .

When the movement of the mouse passes the value set for "threshold", the software will start to move the cursor more quickly, with a greater rate factor. Usually, the user can set the value of the second rate factor by changing the "acceleration" setting.

Operating systems sometimes apply acceleration, referred to as "ballistics", to the motion reported by the mouse     (Toshiba Satellite A200 Battery)         .

For example, versions of Windows prior to Windows XP doubled reported values above a configurable threshold, and then optionally doubled them again above a second configurable threshold . These doublings applied separately in the X and Y directions, resulting in very nonlinear response      (Toshiba Satellite 1200 Battery)     .

Starting with Windows XP and for many OS versions for Apple Macintosh, computers use a ballistics calculation that compensates for screen-resolution in a slightly different way, which affects the way the mouse feels.[citation needed] Ballistics are further affected by the choice of driver software       (Toshiba NB100 Battery)         .


Main article: Mousepad

Engelbart's original mouse did not require a mousepad; the mouse had two large wheels which could roll on virtually any surface. However, most subsequent mechanical mice starting with the steel roller ball mouse have required a mousepad for optimal performance       (Toshiba Satellite M300 Battery)         .

The mousepad, the most common mouse accessory, appears most commonly in conjunction with mechanical mice, because in order to roll smoothly, the ball requires more friction than common desk surfaces usually provide. So-called "hard mousepads" for gamers or optical/laser mice also exist       (Dell INSPIRON 1525 battery)          .

Although most optical and laser mice do not require a pad, some users find that using a mousepad provides more comfort and less jitter of the cursor on the display. Whether to use a hard or soft mousepad with an optical mouse is largely a matter of personal preference. One exception occurs when the desk surface creates problems for the optical or laser tracking, for example, a transparent or reflective surface         (SONY VAIO VGN-FZ280E Battery)     .

Other cases may involve keeping desk or table surfaces free of scratches and deterioration; when the grain pattern on the surface causes inaccurate tracking of the cursor, or when the mouse-user desires a more comfortable mousing surface to work on and reduced collection of debris under the mouse         (SONY VAIO VGN-FZ410 Battery)       .

In the marketplace

Around 1981 Xerox included mice with its Xerox Star, based on the mouse used in the 1970s on the Alto computer at Xerox PARC. Sun Microsystems, Symbolics, Lisp Machines Inc., and Tektronix also shipped workstations with mice, starting in about 1981. Later, inspired by the Star, Apple Computer released the Apple Lisa, which also used a mouse       (SONY VAIO VGN-FZ160 Battery)      .

However, none of these products achieved large-scale success. Only with the release of the Apple Macintosh in 1984 did the mouse see widespread use.

The Macintosh design, commercially successful and technically influential, led many other vendors to begin producing mice or including them with their other computer products (in 1985, Atari ST, Commodore Amiga, Windows 1.0, and GEOS for the Commodore 64). The widespread adoption of graphical user interfaces in the software of the 1980s and 1990s made mice all but indispensable for controlling computers      (SONY VAIO VGN-FZ38M Battery)       .

In November 2008, Logitech built their billionth mouse .

Englebart's mouse did use a mouse pad. In 1968, Jack Kelley, from the Herman Miller Research Division located in Ann Arbor, MI, designed a portable console for computer input, that could be used in a variety locations. The console also attached to an office chair which Englebart used in his presentation to the 1968 Fall Computer Conference in San Francisco. The console consisted of a keyboard and two platforms for the usage of the "mouse". These platforms, surfaces with naugahide (vinyl) were the first pads designed specifically for mouse operation         (SONY VAIO VGN-FZ21m Battery)         .

Use in gaming

Mice often function as an interface for PC-based computer games and sometimes for video game consoles.

First-person shooters

Due to the cursor-like nature of the crosshairs in first-person shooters (FPS), a combination of mouse and keyboard provides a popular way to play FPS games. Players use the X-axis of the mouse for looking (or turning) left and right, leaving the Y-axis for looking up and down          (SONY VAIO VGN-FZ18m Battery)         .

The left button usually controls primary fire. Many gamers prefer this primarily in FPS games over a gamepad or joypad because it allows them to look around easily, quickly and accurately. If the game supports multiple fire-modes, the right button often provides secondary fire from the selected weapon. The right button may also provide bonus options for a particular weapon, such as allowing access to the scope of a sniper rifle or allowing the mounting of a bayonet or silencer      (SONY VAIO VGN-FZ11m Battery)      .

Gamers can use a scroll wheel for changing weapons, or for controlling scope-zoom magnification. On most FPS games, programming may also assign more functions to additional buttons on mice with more than three controls. A keyboard usually controls movement (for example, WASD, for moving forward, left, backward and right, respectively) and other functions such as changing posture     (SONY VAIO VGN-FZ11z Battery)        .

Since the mouse serves for aiming, a mouse that tracks movement accurately and with less lag (latency) will give a player an advantage over players with less accurate or slower mice.

An early technique of players, circle strafing, saw a player continuously strafing while aiming and shooting at an opponent by walking in circle around the opponent with the opponent at the center of the circle      (SONY VAIO VGN-FZ11l Battery)         .

Players could achieve this by holding down a key for strafing while continuously aiming the mouse towards the opponent.

Games using mice for input have such a degree of popularity that many manufacturers, such as Logitech, Cyber Snipa, Razer USA Ltd and SteelSeries, make peripherals such as mice and keyboards specifically for gaming. Such mice may feature adjustable weights, high-resolution optical or laser components, additional buttons, ergonomic shape, and other features such as adjustable DPI          (SONY VAIO VGN-FZ31z Battery)            .

Many games, such as first- or third-person shooters, have a setting named "invert mouse" or similar (not to be confused with "button inversion", sometimes performed by left-handed users) which allows the user to look downward by moving the mouse forward and upward by moving the mouse backward (the opposite of non-inverted movement)      (Dell Studio 1555 Battery)        .

This control system resembles that of aircraft control sticks, where pulling back causes pitch up and pushing forward causes pitch down; computer joysticks also typically emulate this control-configuration.

After id Software's Doom, the game that popularized FPS games but which did not support vertical aiming with a mouse (the y-axis served for forward/backward movement), competitor 3D Realms' Duke Nukem 3D became one of the first games that supported using the mouse to aim up and down     (Dell Vostro 1720 Battery)           .

This and other games using the Build engine had an option to invert the Y-axis. The "invert" feature actually made the mouse behave in a manner that users now regard as non-inverted (by default, moving mouse forward resulted in looking down). Soon after, id Software released Quake, which introduced the invert feature as users now know it. Other games using the Quake engine have come on the market following this standard, likely due to the overall popularity of Quake       (Dell Vostro 1500 Battery)    .

Home consoles

In 1988 the educational video game system, the VTech Socrates, featured a wireless mouse with an attached mouse pad as an optional controller used for some games. In the early 1990s the Super Nintendo Entertainment System video game system featured a mouse in addition to its controllers. The Mario Paint game in particular used the mouse's capabilities, as did its successor on the Nintendo 64. Sega released official mice for their Genesis/Mega Drive, Saturn and Dreamcast consoles      (Dell Latitude D830 Battery)        .

NEC sold official mice for its PC Engine and PC-FX consoles. Sony Computer Entertainment released an official mouse product for the PlayStation console, and included one along with the Linux for PlayStation 2 kit. However, users can attach virtually any USB mouse to the PlayStation 2 console. In addition the PlayStation 3 also fully supports USB mice. Recently the Wii also has this latest development added on in a recent software update      (Dell Latitude D620 Battery)          .

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