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21 janvier 2011 5 21 /01 /janvier /2011 05:02

A solid-state drive(SSD) is a data storage device that uses solid-state memory to store persistent data. SSDs are distinguished from traditional hard disk drives(HDDs), which are electromechanical devices containing spinning disks and movable read/write heads  (Dell XPS M1210 Batteryhttp://www.hdd-shop.co.uk.

SSDs, in contrast, use microchips which retain data in non-volatile memory chips and contain no moving parts. Compared to traditional HDDs, SSDs are typically less susceptible to physical shock, quieter, and have loweraccess time and latency. SSDs use the same interface as hard disk drives, thus easily replacing them in most applications  (Dell Studio XPS 1340 Battery)   .

As of 2010, most SSDs use NAND-based flash memory, which retains memory even without power. SSDs using volatile random-access memory (RAM) also exist for situations which require even faster access, but do not necessarily need data persistence after power loss, or use external power or batteries to maintain the data after power is removed  (Dell Studio XPS 1640 Battery) .

A hybrid drive combines the features of an HDD and an SSD in one unit.

Early SSDs using RAM and similar technology

The origins of SSDs came from the 1950s using two similar technologies, magnetic core memory and card capacitor read-only store (CCROS)   (Dell Vostro 1710 Battery)    .

These auxiliary memory units, as they were called at the time, emerged during the era of vacuum tube computers. But with the introduction of cheaper drum storage units, their use was discontinued. Later, in the 1970s and 1980s, SSDs were implemented in semiconductor memory for early supercomputers of IBM, Amdahl and Cray  (Dell KM958 battery)       ;

however, the prohibitively high price of the built-to-order SSDs made them quite seldom used.

In 1978, Texas Memory Systems introduced a 16 kilobyte (KB) RAM solid-state drive to be used by oil companies for seismic data acquisition. The following year, StorageTek developed the first modern type of solid-state drive  (Sony VGP-BPS13 battery)    .

The Sharp PC-5000, introduced in 1983, used 128 kilobyte solid-state storage cartridges, containing bubble memory. In 1984 Tall grass Company had a tape back up unit of 40 MB with a solid state 20 MB unit built in. The 20 MB unit could be used instead of a hard drive  (Sony VGP-BPS13/B battery)        .

In September 1986, Santa Clara Systems introduced BatRam, 4 megabyte(MB) mass storage system expandable to 20 MB using 4 MB memory modules. The package included a rechargeable battery to preserve the memory chip contents when the array was not powered       (Sony VGP-BPS13/S battery)      .

1987 saw the entry of EMC Corporation into the SSD market, with drives introduced for the mini-computer market. However, EMC exited the business soon after.

Flash-based SSDs

In 1995, M-Systems introduced flash-based solid-state drives  (Sony VGP-BPS13A/B battery)      .

They had the advantage of not requiring batteries to maintain the data in the memory (required by the prior volatile memory systems), but were not as fast as the DRAM-based solutions. Since then, SSDs have been used successfully as HDD replacements by the military and aerospace industries, as well as other mission-critical applications  (Sony VGP-BPS13B/B battery)      .

These applications require the exceptional mean time between failures (MTBF) rates that solid-state drives achieve, by virtue of their ability to withstand extreme shock, vibration and temperature ranges.

BiTMICRO made a number of introductions and announcements in 1999 around flash-based SSDs including an 18 gigabyte 3.5 in SSD (Sony VGP-BPL9 battery)     .

Fusion-io announced a PCIe-based SSD with 100,000 input/output operations per second (IOPS) of performance in a single card with capacities up to 320 gigabytes in 2007. At Cebit 2009, OCZ demonstrated a 1 terabyte (TB) flash SSD using a PCI Express ×8 interface. It achieves a maximum write speed of 654 megabytes per second (MB/s) and maximum read speed of 712 MB/s (Sony VGP-BPS13B/B battery)  .

In December 2009, Micron Technology announced the world's first SSD using a 6 gigabits per second (Gbit/s) or 768 (MB/s) SATA interface.

Enterprise flash drives

Enterprise flash drives(EFDs) are designed for applications requiring high I/O performance (IOPS), reliability, and energy efficiencySony VGP-BPL15 battery.

In most cases an EFD is an SSD with a higher set of specifications compared to SSDs which would typically be used in notebook computers. The term was first used by EMC in January 2008, to help them identify SSD manufacturers who would provide products meeting these higher standards  Dell Inspiron E1505 battery.

There are no standards bodies who control the definition of EFDs, so any SSD manufacturer may claim to produce EFDs when they may not actually meet the requirements. Likewise there may be other SSD manufacturers that meet the EFD requirements without being called EFDs    Dell Latitude E6400 battery.

Secure digital card drives

Secure digital cards are particularly simple and inexpensive SSDs though an equally inexpensive USB flash memory adapter may be needed to attach it if the computer does not have a built-in SD flashmemory card reader(/writer). These cards can boot live SD operating systems (see Applications)  HP Pavilion dv6000 Battery.

Architecture and function

The key components of an SSD are the controller and the memory to store the data. The primary memory component in an SSD had been DRAM volatile memory since they were first developed, but since 2009 it is more commonly NAND flash non-volatile memory  SONY VAIO VGN-FZ Battery.

Other components play a less significant role in the operation of the SSD and vary between manufacturers.

Controller

Every SSD includes a controller that incorporates the electronics that bridge the NAND memory components to the host computerSONY VAIO VGN-FZ18 Battery.

The controller is an embedded processor that executes firmware-level code and is one of the most important factors of SSD performance. Some of the functions performed by the controller include    SONY VAIO VGN-FZ180E Battery:

  • Error correction (ECC)
  • Wear leveling
  • Bad block mapping
  • Read scrubbing and read disturb management
  • Read and write caching
  • Garbage collection
  • Encryption      SONY VAIO VGN-FZ220E Battery

The performance of the SSD can scale with the number of parallel NAND flash chips used in the device. A single NAND chip is relatively slow, due to narrow (8/16 bit) asynchronous IO interface, and additional high latency of basic IO operations (typical for SLC NAND, ~25 ?s to fetch a 4K page from the array to the IO buffer on a read, ~250 ?s to commit a 4K page from the IO buffer to the array on a write, ~2 ms to erase a 256 kiB block)  SONY VAIO VGN-FZ340E Battery.

When multiple NAND devices operate in parallel inside an SSD, the bandwidth scales, and the high latencies can be hidden, as long as enough outstanding operations are pending and the load is evenly distributed between devices. Micron and Intel initially made faster SSDs by implementing data striping (similar to RAID 0) and interleaving in their architecture  SONY VAIO VGN-FZ430E Battery.

This enabled the creation of ultra-fast SSDs with 250 MB/s effective read/write speeds.

Memory

Flash memory-based

Most SSD manufacturers use non-volatile NAND flash memory in the construction of their SSDs due to the lower cost compared to DRAM and the ability to retain the data without a constant power supply, ensuring data persistence through sudden power outagesSONY VAIO VGN-FZ460E Battery.

Flash memory SSDs are slower than DRAM solutions, and some early designs were even slower than HDDs after continued use. This problem was resolved by controllers that came out in 2009 and later.

Flash memory-based solutions are typically packaged in standard disk drive form factors (1.8-, 2.5-, and 3.5-inch), or smaller unique and compact layouts due to the compact memory      SONY VAIO VGN-FZ480E Battery.

Single-level cell (SLC) vs multi-level cell (MLC)

Lower priced drives usually use multi-level cell (MLC) flash memory, which is slower and less reliable than single-level cell (SLC) flash memory. This can be mitigated or even reversed by the internal design structure of the SSD, such as interleaving, changes to writing algorithms, and higher over-provisioning (more excess capacity) with which the wear-leveling algorithms can work    SONY VAIO VGN-FZ4000 Battery.

DRAM-based

SSDs based on volatile memory such as DRAM are characterized by ultrafast data access, generally less than 10 microseconds, and are used primarily to accelerate applications that would otherwise be held back by the latency of flash SSDs or traditional HDDsSONY VAIO VGN-FZ31E Battery.

DRAM-based SSDs usually incorporate either an internal battery or an external AC/DC adapter and backup storage systems to ensure data persistence while no power is being supplied to the drive from external sources. If power is lost, the battery provides power while all information is copied from random access memory (RAM) to back-up storage  SONY VAIO VGN-FZ31B Battery.

When the power is restored, the information is copied back to the RAM from the back-up storage, and the SSD resumes normal operation (similar to the hibernate function used in modern operating systems).

These types of SSD are usually fitted with the same type of DRAM modules used in regular PCs and servers, allowing them to be swapped out and replaced with larger modules  SONY VAIO VGN-FZ31J Battery.

A remote, indirect memory-access disk (RIndMA Disk)uses a secondary computer with a fast network or (direct) Infiniband connection to act like a RAM-based SSD, but the new faster flash memory based SSDs already available in 2009 are making this option not as cost effective  SONY VAIO VGN-FZ31M Battery.

Cache or buffer

A flash-based SSD typically uses a small amount of DRAM as a cache, similar to the cache in Hard disk drives. A directory of block placement and wear leveling data is also kept in the cache while the drive is operating. None of the user's data is typically stored in the cache  SONY VAIO VGN-FZ31Z Battery.

One particular SSD controller manufacturer, SandForce, is noted for not using an external DRAM cache on their designs. They still achieve very high performance even without the aid of the cache. Eliminating the external DRAM enables a smaller footprint for the other flash memory components in order to build even smaller SSDs  SONY VAIO VGN-FZ38M Battery.

Battery or super capacitor

Another component in higher performing SSDs is a capacitor or some form of battery. These are necessary to maintain data integrity such that the data in the cache can be flushed to the drive when power is dropped; some may even hold power long enough to maintain data in the cache until power is resumed    SONY VGP-BPS8 Battery.

In the case of MLC flash memory, a problem called lower page corruptioncan occur when MLC flash memory loses power while programming an upper page. The result is data written previously and presumed safe can be corrupted if the memory is not supported by a super capacitor in the event of a sudden power loss  SONY VGP-BPS13 Battery.

This problem does not exist with SLC flash memory.

Host interface

The host interface is not specifically a component of the SSD, but it is a key part of the drive. The interface is usually incorporated into the controller discussed above. The interface is generally one of the interfaces found in HDDs  SONY VGP-BPS13/S Battery.

They include:

  • Serial ATA
  • Serial attached SCSI (generally found on servers)
  • PCI Express
  • Fibre Channel (almost exclusively found on servers)SONY VGP-BPS13A/B Battery
  • USB
  • Parallel ATA (IDE) interface (mostly replaced by SATA)
  • (Parallel) SCSI (generally found on servers; mostly replaced by SAS)

Form factor

The size and shape of any device is largely driven by the size and shape of the components used to make that deviceSONY VGP-BPS13B/B Battery.

Traditional HDDs and optical drives are designed around the rotating platter oroptical disc along with the spindle motor inside. If an SSD is made up of various interconnected integrated circuits (ICs) and an interface connector, then its shape could be virtually anything imaginable because it is no longer limited to the shape of rotating media drivesSONY VGP-BPS13A/S Battery.

Some solid state storage solutions come in a larger chassis that may even be a rack-mount form factor with numerous SSDs inside. They would all connect to a common bus inside the chassis and connect outside the box with a single connectorSONY VGP-BPS13AS Battery.

Standard HDD form factors

The benefit of using a current HDD form factor would be to take advantage of the extensive infrastructure already in place to mount and connect the drives to the host system.These traditional form factors are known by the size of the rotating media, e.g., 5.25", 3.5", 2.5", 1.8", not by the dimensions of the drive casing  Dell Inspiron 1320n Battery.

Box form factors

Many of the DRAM-based solutions use a box that is often designed to fit in a rack-mount system. The number of DRAM components required to get sufficient capacity to store the data along with the backup power supplies requires a larger space than traditional HDD form factors    Dell Inspiron 1464 Battery.

Bare-board form factors

Form factors which were more common to memory modules are now being used by SSDs to take advantage of their flexibility in laying out the components. Some of these include PCIe, mini PCIe,mini-DIMM, MO-297, and many more  Dell Inspiron 1564 Battery.

At least one manufacturer, InnoDisk, is producing a drive that sits directly on the SATA connector on the motherboard without any other support or mechanical mount. The SATADIMM from Viking Modular uses an empty DDR3 DIMM slot on the motherboard to provide power to the drive with a separate SATA connector to provide the data connection back to the computer  Dell Inspiron 1764 Battery.

The result is an easy to install SSD with a capacity equal to drives that typically take a full 2.5 in expansion slot. Some SSDs are based on the PCIe form factor and connect both the data interface and power through the PCIe connector to the host. These drives can use either direct PCIe flash controllers or a PCIe-to-SATA bridge device which then connects to SATA flash controller(s)Dell Studio 1450 Battery.

Comparison of SSD with hard disk drives

The disassembled components of a hard disk drive (left) and of the PCB and components of a solid-state drive (right)

Making a comparison between SSDs and ordinary (spinning) HDDs is difficult. Traditional HDD benchmarks are focused on finding the performance aspects where they are weak, such as rotational latency time and seek time  Dell Studio 1457 Battery.

As SSDs do not spin, or seek, they may show huge superiority in such tests. However, SSDs have challenges with mixed reads and writes, and their performance may degrade over time. SSD testing must start from the (in use) full disk, as the new and empty (fresh out of the box) disk may have much better write performance than it would show after only weeks of use  Dell Latitude D610 Battery.

Comparisons reflect typical characteristics, and may not hold for a specific device.

Commercialization

Cost and capacity

The technological trend is a 2 year 50% decline in costs, while capacities continue to double at the same rate. As a result, flash-based solid-state drives are becoming increasingly popular in markets such as notebook PCs and sub-notebooks for enterprises, Ultra-Mobile PCs (UMPC), and Tablet PCs for the healthcare and consumer electronics sectorsAcer Aspire One battery.

Availability

Solid-state drive (SSD) technology has been marketed to the military and niche industrial markets since the mid-1990s.

Along with the emerging enterprise market, SSDs have been appearing in ultra-mobile PCs and a few lightweight laptop systems, adding significantly to the price of the laptop, depending on the capacity, form factor and transfer speeds  Toshiba Satellite P10 Battery.

As of 2008, some manufacturers have begun shipping affordable, fast, energy-efficient drives priced at $350 to computer manufacturers. For low-end applications, a USB flash drive may be obtained for $10 to $100 or so, depending on capacity, or a CompactFlash card may be paired with a CF-to-IDE or CF-to-SATA converter at a similar cost  SONY VGN-FZ210CE Battery.

Either of these requires that write-cycle endurance issues be managed, either by not storing frequently written files on the drive, or by using a flash file system. Standard CompactFlash cards usually have write speeds of 7 to 15 MB/s while the more expensive upmarket cards claim speeds of up to 40 MB/s    Dell Precision M70 Battery.

One of the first mainstream releases of SSD was the XO Laptop, built as part of the One Laptop Per Child project. Mass production of these computers, built for children in developing countries, began in December 2007. These machines use 1,024 MiB SLC NAND flash as primary storage which is considered more suitable for the harsher than normal conditions in which they are expected to be used      Toshiba Satellite L305 Battery.

Dell began shipping ultra-portable laptops with SanDisk SSDs on April 26, 2007. Asus released the Eee PCsubnotebook on October 16, 2007, and after a successful commercial start in 2007, it was expected to ship several million PCs in 2008, with 2, 4 or 8 gigabytes of flash memory      Toshiba Satellite T4900 Battery.

On January 31, 2008, Apple Inc. released the MacBook Air, a thin laptop with optional 64 GB SSD. The Apple store cost was $999 more for this option, as compared to that of an 80 GB 4200 rpm Hard Disk Drive.Another option, the Lenovo ThinkPad X300 with a 64 gigabyte SSD, was announced by Lenovo in February 2008, and is, as of 2008, available to consumers in some countries  Toshiba PA3399U-2BRS battery.

On August 26, 2008, Lenovo released ThinkPad X301 with 128GB SSD option which adds approximately $200 US.

In 2008, low end netbooks appeared with SSDs. In 2009, SSDs began to appear in laptops.

On January 14, 2008, EMC became the first enterprise storage vendor to ship flash-based SSDs into its product portfolioToshiba Satellite A200 Battery.

In late 2008, Sun released the Sun Storage 7000 Unified Storage Systems(codenamed Amber Road), which use both solid state drives and conventional hard drives to take advantage of the speed offered by SSDs and the economy and capacity offered by conventional hard disks  Toshiba Satellite 1200 Battery.

Dell began to offer optional 256 GB solid state drives on select notebook models in January 2009.

In May 2009, Toshiba launched a laptop with a 512 GB SSD.

As of October 2010, Apple's MacBook Air line carry solid state drives, standard  Toshiba Satellite M300 Battery.

In December 2010, OCZ RevoDrive X2 PCIe SSD available in 100GB to 960GB capacities delivering superior speeds over 740MB/s sequential speeds and random small file writes up to 120,000 IOPS    Sony Vaio PCG-5G2L Battery.

Quality and performance

SSD is a rapidly developing technology. In November 2010, Tom's Hardware made recommendations based on user needs. "You usually won’t regret buying an SSD with a SandForce SF-1200 controller. The balance between throughput, I/O performance, and application performance is still impressive. Corsair, G.Skill, Patriot, OCZ, Runcore, and others have suitable offerings  Sony Vaio PCG-5G3L Battery.

Look for best prices, warranty, and maybe an installation kit for your desktop PC if needed. If you want to maximize throughput, you have no alternative but to purchase Crucial’s RealSSD C300. Mobile users can only get rock bottom power consumption if they stay with Toshiba hardware, which isn’t the fastest        Sony Vaio PCG-5J1L Battery.

Intel SSDs offer a good compromise between power and performance, but you have to be aware of their limited write performance. Samsung’s 470-series only shows marginal weaknesses across our benchmark suite. If Samsung were to price the drive more aggressively, it would be a more compelling option      Sony Vaio PCG-5K2L Battery."

Performance of flash SSDs are difficult to benchmark. In a test done by Xssist, using IOmeter, 4 KB RANDOM 70/30 RW, queue depth 4, the IOPS delivered by the Intel X25-E 64 GB G1 started around 10,000 IOPs, and dropped sharply after 8 minutes to 4,000 IOPS, and continued to decrease gradually for the next 42 minutes    Sony Vaio PCG-5J2L Battery.

IOPS vary between 3,000 to 4,000 from around the 50th minutes onwards for the rest of the 8+ hours test run.

This only affected write performance with consumer grade drives. Enterprise grade drives avoid this problem by overprovisioning, and by employing wear-leveling algorithms that only move data around when the drives are not being heavily utilized   Sony Vaio PCG-5K1L Battery.

Applications

Until 2009, SSDs were mainly used in those aspects of mission critical applications where the speed of the storage system needed to be as fast as possible        Sony Vaio PCG-5L1L Battery.

Since flash memory has become a common component of SSDs, the falling prices and increased densities have made it more financially attractive for many other applications. Organizations that can benefit from faster access of system data include equity trading companies, telecommunication corporations, and video streaming and editing firms  Sony Vaio PCG-6S2L Battery.

The list of applications which could benefit from faster storage is vast. Any company can assess the ROI from adding SSDs to their own applications to best understand if that will be cost effective for them.

Flash-based Solid-state drives can be used to create network appliances from general-purpose PC hardware  Sony Vaio PCG-6S3L Battery.

A write protected flash drive containing the operating system and application software can substitute for larger, less reliable disk drives or CD-ROMs. Appliances built this way can provide an inexpensive alternative to expensive router and firewall hardware.

SSDs based on an SD card with a live SD operating system are easily write-locked      Sony Vaio PCG-6V1L Battery.

Combined with a cloud computing environment or other writable medium, to maintain persistence, an OS bootedfrom a write-locked SD card is robust, rugged and reliable and impervious to permanent corruption. If the running OS degrades simply turning the machine off and then on returns it back to its initial virgin uncorrupted state and thus is particularly solid  Sony Vaio PCG-6W1L Battery.

The SD card installed OS does not require removal of corrupted components since it was write-locked though any written media may need to be restored.

SSD optimized file systems

There are a number of file systems which are optimized for solid-state drives   Sony Vaio PCG-6W2L Battery.

Some of the more popular or notable are listed below.

Microsoft Windows

Versions of Windows prior to Windows 7 are optimized for hard disk drives rather than SSDs  Sony Vaio PCG-6W3L Battery.

Windows Vista includes ReadyBoost to exploit characteristics of USB-connected flash devices, but for SSDs it only improves the partition alignment to prevent read-modify-write operations because the SSD is typically aligned on 4 KB sectors and the OS is based on 512 byte sectors and they are not aligned  Sony Vaio PCG-7111L Battery.

The proper alignment really does not help the SSD's endurance over the life of the drive. Some Vista operations, if not disabled, can shorten the life of the SSD. Disk defragmentationshould be disabled because the location of the file components on an SSD don't significantly impact its performance    Sony Vaio PCG-7112L Battery,

but moving the files to make them contiguous using the Windows Defrag routine will cause write wear on the limited number of P/E cycles on the SSD. The Superfetch feature will not materially change the performance of the system and causes additional overhead on the system and SSD, although it does not cause wear    Sony Vaio PCG-7113L Battery.

Windows 7 is optimized for SSDs as well as for hard disks. The OS looks for the presence of an SSD and operates differently with that drive. If an SSD is present, Windows 7 will disable disk defragmentation, Superfetch, ReadyBoost, and other boot-time and application prefetching operations      Sony Vaio PCG-7133L Battery.

It also includes support for the TRIM command to reduce garbage collection of data which the OS has already determined is no longer valid (without TRIM the SSD would be unaware of this data being invalid).

ZFS

Solaris, as of 10u6 (released in October 2008), and recent versions of OpenSolaris and Solaris Express Community Edition on which OpenSolaris is based, can use SSDs as a performance booster forZFS      Sony Vaio PCG-7Z2L Battery.

There are two available modes—using an SSD for the ZFS Intent Log (ZIL), which is used every time a synchronous write to the disk occurs (a low write-latency SSD should be used for the ZIL), or for the L2ARC (Level 2 Adaptive Replacement Cache), which is used to cache data for reading (the L2ARC is infrequently written, and low write-latency SSD is thus not needed)  Sony Vaio PCG-8Y1L Battery.

When used either alone or in combination, large increases in performance are generally seen.

Linux systems

The vital TRIM function is supported by the Linux OS starting with 2.6.33 kernel (available early 2010). However, support amongst various filesystems is still inconsistent or not present. Proper partition alignment is also not carried out by installation software  Sony Vaio PCG-8Y2L Battery.

Write precompensation (abbreviated WPcom in the literature) is a technical aspect of hard disk design. It is the use of a stronger magnetic field to write data in sectors that are closer to the center of the disk. In constant angular velocity recording, in which the disk spins at a constant speed no matter where the data is written    Sony Vaio PCG-8Z1L Battery,

the sectors closest to the spindle are packed tighter than the outer sectors and so require a stronger magnetic field to write the data.

In the past one of the hard disk parameters stored in a PC's CMOS memory is the WPcom number, a marker of the track where precompensation begins      Dell Studio 1555 battery.

Modern hard disks rarely access the CMOS memory and internally store the WPcom number if write precompensation is used.

Multimediais media and content that uses a combination of different content forms. The term can be used as a noun (a medium with multiple content forms) or as an adjective describing a medium as having multiple content forms  Sony Vaio PCG-8Z2L Battery.

The term is used in contrast to media which only use traditional forms of printed or hand-produced material. Multimedia includes a combination of text, audio, still images, animation, video, and interactivity content forms  Sony VAIO PCG-5G2L Battery.

Multimedia is usually recorded and played, displayed or accessed by information content processing devices, such as computerized and electronic devices, but can also be part of a live performance.Multimedia(as an adjective) also describes electronic media devices used to store and experience multimedia content      Sony VAIO PCG-5G3L Battery.

Multimedia is distinguished from mixed media in fine art; by including audio, for example, it has a broader scope. The term "rich media" is synonymous for interactive multimedia. Hypermedia can be considered one particular multimedia application  Sony VAIO PCG-5J1L Battery.

Categorization of multimedia

Multimedia may be broadly divided into linearand non-linearcategories. Linear active content progresses without any navigational control for the viewer such as a cinema presentation  Sony VAIO PCG-5K2L Battery.

Non-linear content offers user interactivity to control progress as used with a computer game or used in self-paced computer based training. Hypermedia is an example of non-linear content.

Multimedia presentations can be live or recorded    Sony VAIO PCG-5J2L Battery.

A recorded presentation may allow interactivity via a navigation system. A live multimedia presentation may allow interactivity via an interaction with the presenter or performer.

Major characteristics of multimedia

Multimedia presentationsmay be viewed in person on stage, projected, transmitted, or played locally with a media player  Sony VAIO PCG-5K1L Battery.

A broadcast may be a live or recorded multimedia presentation. Broadcasts and recordings can be either analog or digital electronic media technology. Digital online multimedia may be downloaded or streamed. Streaming multimedia may be live or on-demand  Sony VAIO PCG-5L1L Battery.

Multimedia games and simulationsmay be used in a physical environment with special effects, with multiple users in an online network, or locally with an offline computer, game system, orsimulator.

The various formats of technological or digital multimedia may be intended to enhance the users' experience, for example to make it easier and faster to convey information  Sony VAIO PCG-6S2L Battery.

Or in entertainment or art, to transcend everyday experience.

Enhanced levels of interactivity are made possible by combining multiple forms of media content. Online multimedia is increasingly becoming object-oriented and data-driven, enabling applications with collaborative end-user innovation and personalization on multiple forms of content over time  Sony VAIO PCG-6S3L Battery.

Examples of these range from multiple forms of content on Web sites like photo galleries with both images (pictures) and title (text) user-updated, to simulations whose co-efficients, events, illustrations, animations or videos are modifiable, allowing the multimedia "experience" to be altered without reprogramming    Sony VAIO PCG-6V1L Battery.

In addition to seeing and hearing,Haptic technology enables virtual objects to be felt. Emerging technology involving illusions of taste and smell may also enhance the multimedia experience        Sony VAIO PCG-6W1L Battery.

Terminology

History of the term

The term "multimedia" was coined by Bob Goldstein (later 'Bobb Goldsteinn') to promote the July 1966 opening of his "LightWorks at L'Oursin" show at Southampton, Long Island        Sony VAIO PCG-6W2L Battery.

On August 10, 1966, Richard Albarino of Variety borrowed the terminology, reporting: “Brainchild of songscribe-comic Bob (‘Washington Square’) Goldstein, the ‘Lightworks’ is the latest multi-mediamusic-cum-visuals to debut as discothèque fare.” . Two years later, in 1968, the term “multimedia” was re-appropriated to describe the work of a political consultant, David Sawyer, the husband of Iris Sawyer—one of Goldstein’s producers at L’Oursin  Sony VAIO PCG-6W3L Battery.

Multimedia (multi-image) setup for the 1988 Ford New Car Announcement Show, August, 1987, Detroit, MI

In the intervening forty years, the word has taken on different meanings. In the late 1970s the term was used to describe presentations consisting of multi-projector slide shows timed to an audio track  Sony VAIO PCG-7111L Battery.

However, by the 1990s 'multimedia' took on its current meaning.

In the 1993 first edition of McGraw-Hill’s Multimedia: Making It Work, Tay Vaughan declared “Multimedia is any combination of text, graphic art, sound, animation, and video that is delivered by computer    Sony VAIO PCG-7112L Battery.

When you allow the user – the viewer of the project – to control what and when these elements are delivered, it is interactive multimedia. When you provide a structure of linked elements through which the user can navigate, interactive multimedia becomeshypermedia Sony VAIO PCG-7113L Battery.”

The German language society, Gesellschaft für deutsche Sprache, decided to recognize the word's significance and ubiquitousness in the 1990s by awarding it the title of 'Word of the Year' in 1995. The institute summed up its rationale by stating "[Multimedia] has become a central word in the wonderful new media world      Sony VAIO PCG-7133L Battery"

In common usage, the term multimedia refers to an electronically delivered combination of media including video, still images, audio, text in such a way that can be accessed interactively. Much of the content on the web today falls within this definition as understood by millions      Sony VAIO PCG-7Z1L Battery.

Some computers which were marketed in the 1990s were called "multimedia" computers because they incorporated a CD-ROM drive, which allowed for the delivery of several hundred megabytes of video, picture, and audio data.

Word usage and context

Since media is the plural of medium, the term "multimedia" is a pleonasm if "multi" is used to describe multiple occurrences of only one form of media such as a collection of audio CDs   Sony VAIO PCG-7Z2L Battery.

This is why it's important that the word "multimedia" is used exclusively to describe multiple formsof media and content.

The term "multimedia" is also ambiguous. Static content (such as a paper book) may be considered multimedia if it contains both pictures and text or may be considered interactive if the user interacts by turning pages at will. Books may also be considered non-linear if the pages are accessed non-sequentially  Sony VAIO PCG-8Y1L Battery.

The term "video", if not used exclusively to describe motion photography, is ambiguous in multimedia terminology. Videois often used to describe the file format, delivery format, or presentation format instead of "footage"which is used to distinguish motion photography from "animation"ofrendered motion imagery      Sony VAIO PCG-8Y2L Battery.

Multiple forms of information content are often not considered modern forms of presentation such as audio or video. Likewise, single forms of information content with single methods of information processing (e.g. non-interactive audio) are often called multimedia, perhaps to distinguish static media from active media      Sony VAIO PCG-8Z1L Battery.

In the Fine arts, for example, Leda Luss Luyken'sModulArt brings two key elements of musical composition and film into the world of painting: variation of a theme and movement of and within a picture, making ModulArtan interactive multimedia form of art  Sony VAIO PCG-8Z2L Battery.

Performing arts may also be considered multimedia considering that performers and props are multiple forms of both content and media        Sony VGP-BPS21 Battery.

Usage

Multimedia finds its application in various areas including, but not limited to, advertisements, art, education, entertainment, engineering, medicine,mathematics, business, scientific research and spatial temporal applications. Several examples are as follows        Sony VGP-BPS21A Battery:

Creative industries

Creative industries use multimedia for a variety of purposes ranging from fine arts, to entertainment, to commercial art, to journalism, to media and software services provided for any of the industries listed below. An individual multimedia designer may cover the spectrum throughout their career      Sony VGP-BPS21B Battery.

Request for their skills range from technical, to analytical, to creative.

Commercial

Much of the electronic old and new media used by commercial artists is multimedia. Exciting presentations are used to grab and keep attention inadvertising        Sony VGP-BPS21/S Battery.

Business to business, and interoffice communications are often developed by creative services firms for advanced multimedia presentations beyond simple slide shows to sell ideas or liven-up training. Commercial multimedia developers may be hired to design for governmental services and nonprofit services applications as well      Sony VGP-BPS21A/B Battery.

Entertainment and fine arts

In addition, multimedia is heavily used in the entertainment industry, especially to develop special effects in movies and animations. Multimedia games are a popular pastime and are software programs available either as CD-ROMs or online. Some video games also use multimedia features    SONY VGP-BPS21 Battery.

Multimedia applications that allow users to actively participate instead of just sitting by as passive recipients of information are called Interactive Multimedia. In the Arts there aremultimedia artists, whose minds are able to blend techniques using different media that in some way incorporates interaction with the viewer      SONY VGP-BPS21A Battery.

One of the most relevant could be Peter Greenaway who is melding Cinema with Opera and all sorts of digital media. Another approach entails the creation of multimedia that can be displayed in a traditional fine arts arena, such as an art gallery. Although multimedia display material may be volatile, the survivability of the content is as strong as any traditional media  SONY VGP-BPS21B Battery.

Digital recording material may be just as durable and infinitely reproducible with perfect copies every time.

Education

In Education, multimedia is used to produce computer-based training courses (popularly called CBTs) and reference books like encyclopedia and almanacs        SONY VGP-BPS21/S Battery.

A CBT lets the user go through a series of presentations, text about a particular topic, and associated illustrations in various information formats. Edutainmentis an informal term used to describe combining education with entertainment, especially multimedia entertainment      SONY VGP-BPS21A/B Battery.

Learning theory in the past decade has expanded dramatically because of the introduction of multimedia. Several lines of research have evolved (e.g. Cognitive load, Multimedia learning, and the list goes on). The possibilities for learning and instruction are nearly endless       (SONY VGP-BPS13/Q Battery)        .

The idea of media convergence is also becoming a major factor in education, particularly higher education. Defined as separate technologies such as voice (and telephony features), data (and productivity applications) and video that now share resources and interact with each other      SONY VGP-BPS13/Q Battery,

synergistically creating new efficiencies, media convergence is rapidly changing the curriculum in universities all over the world. Likewise, it is changing the availability, or lack thereof, of jobs requiring this savvy technological skill.

Journalism

Newspaper companies all over are also trying to embrace the new phenomenon by implementing its practices in their work  SONY VGP-BPS13B/Q Battery.

While some have been slow to come around, other major newspapers like The New York Times, USA Today and The Washington Post are setting the precedent for the positioning of the newspaper industry in a globalized world.

News reporting is not limited to traditional media outlets      SONY VGP-BPS13B/Q Battery.

Freelance journalists can make use of different new media to produce multimedia pieces for their news stories. It engages global audiences and tells stories with technology, which develops new communication techniques for both media producers and consumers      SONY VGP-BPS13A/Q Battery.

Common Language Project is an example of this type of multimedia journalism production.

Engineering

Software engineers may use multimedia in Computer Simulations for anything from entertainment to training such as military or industrial training. Multimedia for software interfaces are often done as a collaboration between creative professionals and software engineers        SONY VGP-BPS13A/Q Battery.

Industry

In the Industrial sector, multimedia is used as a way to help present information to shareholders, superiors and coworkers. Multimedia is also helpful for providing employee training, advertising and selling products all over the world via virtually unlimited web-based technology          WD passport essential (500GB/640GB).

Mathematical and scientific research

In mathematical and scientific research, multimedia is mainly used for modeling and simulation. For example, a scientist can look at a molecular model of a particular substance and manipulate it to arrive at a new substance. Representative research can be found in journals such as the Journal of Multimedia        WD passport essential (250GB/320GB).

Medicine

In Medicine, doctors can get trained by looking at a virtual surgery or they can simulate how the human body is affected by diseases spread by viruses and bacteria and then develop techniques to prevent it        WD  passport essential SE (750GB/1TB)      .

Document imaging

Document imaging is a technique that takes hard copy of an image/document and converts it into a digital format (for example, scanners)    WD  passport elite(250GB/320GB).

Disabilities

Ability Media allows those with disabilities to gain qualifications in the multimedia field so they can pursue careers that give them access to a wide array of powerful communication forms      WD passport elite(500GB/640GB).

Miscellaneous

In Europe, the reference organisation for Multimedia industry is the European Multimedia Associations Convention (EMMAC).

Structuring information in a multimedia form

Multimedia represents the convergence of text, pictures, video and sound into a single form. The power of multimedia and the Internet lies in the way in which information is linked        WD  passport studio for Mac(320GB/500GB).

Multimedia and the Internet require a completely new approach to writing. The style of writing that is appropriate for the 'on-line world' is highly optimized and designed to be able to be quickly scanned by readers        WD  passport studio for Mac(500GB/640GB).  

A good site must be made with a specific purpose in mind and a site with good interactivity and new technology can also be useful for attracting visitors. The site must be attractive and innovative in its design, function in terms of its purpose, easy to navigate, frequently updated and fast to download          WD  Elements series(250GB/320GB).

When users view a page, they can only view one page at a time. As a result, multimedia users must create a ‘mental model of information structure’

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Attribute or characteristic

Solid-state drive

Hard disk drive

Spin-up time          Toshiba NB100 Battery

Instantaneous.

May take several seconds. With a large number of drives, spin-up may need to be staggered to limit total power drawn.

Random access time

About 0.1 ms - many times faster than HDDs because data is accessed directly from the flash memory

Ranges from 5–10 ms due to the need to move the heads and wait for the data to rotate under theread/write head

Read latency time Toshiba Satellite M65 battery

Generally low because the data can be read directly from any location; In applications where hard disk seeks are the limiting factor, this results in faster boot and application launch times (see Amdahl's law).

Generally high since the mechanical components require additional time to get aligned

Consistent read performance Toshiba Satellite M60 battery

Read performance does not change based on where data is stored on an SSD

If data is written in a fragmented way, reading back the data will have varying response times

Defragmentation  Dell Latitude D830 Battery

SSDs do not benefit from defragmentation because there is little benefit to reading data sequentially and any defragmentation process adds additional writes on the NAND flash that already have a limited cycle life.

HDDs may require defragmentation after continued operations or erasing and writing data, especially involving large files or where the disk space becomes low.Dell Latitude D620 Battery

Acoustic levels

SSDs have no moving parts and make no sound

HDDs have moving parts (heads, spindle motor) and have varying levels of sound depending upon model

Mechanical reliability        Dell Inspiron Mini 10 Battery

A lack of moving parts virtually eliminates mechanical breakdowns

HDDs have many moving parts that are all subject to failure over time

Susceptibility toenvironmental factorsSony VGN-FW11S Battery

No flying heads or rotating platters to fail as a result of shock, altitude, or vibration

The flying heads and rotating platters are generally susceptible to shock, altitude, and vibration

Magneticsusceptibility Sony VGN-FW11M Battery

No impact on flash memory

Magnets or magnetic surges can alter data on the media

Weight and size Sony VGN-FW139E/H battery

The weight of flash memory and the circuit board material are very light compared to HDDs

Higher performing HDDs require heavier components than laptop HDDs that are light, but not as light as SSDs

Parallel operation Dell Latitude E5400 Battery

Some flash controllers can have multiple flash chips reading and writing at the same time accessing different data at once

HDDs have multiple heads (one per platter) but they are connected, and share one positioning motor.

Write longevity    Dell Latitude E4200 Battery

Solid state drives that use flash memory have a limited number of writes over the life of the drive. SSDs based on DRAM do not have a limited number of writes.

Magnetic media do not have a limited number of writes        Dell Inspiron 300M Battery,       .

Software encryption limitations

NAND flash memory cannot be overwritten, but has to be rewritten to previously erased blocks. If a software encryption program encrypts data already on the SSD, the o

verwritten data is still unsecured, unencrypted, and accessible by a data thief (drive-based hardware encryption does not have this problem). Also data cannot be securely erased by overwriting the original file without special "Secure Erase" procedures built into the drive        Dell Vostro A840 Battery.

HDDs can overwrite data directly on the drive in any particular sector.

Cost

As of October 2010, NAND flash SSDs cost about (US)$1.40–2.00 per GB

As of October 2010, HDDs cost about (US)$0.10/GB for 3.5 in and $0.20/GB for 2.5 in drives

Storage capacity          Dell Studio 1737 battery

As of October 2010, SSDs come in different sizes up to 2TB but are typically 512GB or less

As of October 2010, HDDs are typically 2-3TB or less

Read/write performance symmetry        Dell Inspiron E1505 battery

Less expensive SSDs typically have write speeds significantly lower than their read speeds. Higher performing SSDs and those from particular manufacturers have a balanced read and write speed.[

HDDs generally have symmetrical read and write speeds           Dell RM791 battery

Free block availability andTRIM

SSD write performance is significantly impacted by the availability of free, programmable blocks. Previously written data blocks that are no longer in use can be reclaimed by TRIM; however, even with TRIM, fewer free, programmable blocks translates into reduced performance  Dell XPS M1530 battery.

HDDs are not affected by free blocks or the operation (or lack) of the TRIM command

Power consumption

High performance flash-based SSDs generally require 1/2 to 1/3 the power of HDDs; High performance DRAM SSDs generally require as much power as HDDs and consume power when the rest of the system is shut down. Dell XPS M2010 battery

High performance HDDs generally require between 12-18 watts; drives designed for notebook computers are typically 2 watts.

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