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4 janvier 2011 2 04 /01 /janvier /2011 03:41

A Hybrid Drive, Hybrid Hard Drive (HHD), or Hybrid Hard Disk Drive (H-HDD) is a type of large-buffer computer hard disk drive. It is different from standard hard drives in that it integrates a cacheusing non-volatile memory or even a small solid-state drive (SSD) (Dell XPS M1210 Batteryhttp://www.hdd-shop.co.uk .

Although the cache typically uses non-volatile flash memory, some drives use battery-backed volatile RAM (a hybrid RAM disk). The flash memory buffer can speed up repeated reads to the same location; a RAM buffer speeds both reads and writes, but must be written to backup storage before power is lost (Dell Studio XPS 1340 Battery)  .

In 2007 Seagate and Samsung both introduced hybrid HDDs primarily targeted to OEMs notebook computer manufacturers. Although the technology was initially supported by Microsoft, a number of issues prevented their success over the next year in the market with Windows Vista  (Dell Studio XPS 1640 Battery)     .

In May 2010, Seagate launched the Momentus XT solid state hybrid drive. It adds a new feature they call Adaptive Memory which is said to remove the OS, driver, and software dependency previously required to take advantage of the integrated Flash memory. The SSD portion of this new drive is also now a larger 4 GB, compared to 256 MB in the past      (Dell Vostro 1710 Battery)     .

Benchmark results conducted and published by Seagate of the Momentus XT place the 7200 RPM hybrid drive's performance firmly between high-end 10,000 RPM drives and solid-state drives on a number of tasks, such as system boot time and application launch speed  (Dell KM958 battery)      .

For example, according to these benchmarks, system boot time using this hybrid drive is approximately 41% faster than the same task using a non-hybrid 7200 RPM drive, while a "best-in-class" solid-state drive performs approximately 44% faster than a standard 7200 RPM drive on the same test  (Sony VGP-BPS13 battery)      .

Operation

Unlike most standard hard drives, the hybrid drive in its normal state has its platters at rest, with the motor not consuming power or generating heat  (Sony VGP-BPS13/B battery)      .

Any data written to the hybrid drive is written to the buffer; there is no risk of data loss in the event of power failure as the buffer's flash memory is not volatile. When reading data from the platters extra data is read and stored in buffer memory (which need not be non-volatile flash memory) in the hope of anticipating future requirements as in any disk cache (Sony VGP-BPS13/S battery)  .

Data required for the next boot-up can be stored in the non-volatile buffer before shutting down the computer.

The hybrid drive's platters will spin up to move data from the write buffer to the platters when nearly full, and to read data which is not in the cache  (Sony VGP-BPS13A/B battery)    .

Early estimates place the actual hard drive usage (when the platters are spinning) at anywhere between 1.25% and 10% for typical single users, although there are obviously situations where platter usage will be much higher, such as the encoding or editing of very large video files, producing reports from a database, etc  (Sony VGP-BPS13B/B battery)   .

As of early 2008 the special features of hybrid drives are only taken advantage of by Microsoft's Windows Vista and Windows 7 operating systems. The files required for booting are stored in the fast flash memory, reducing boot time by about 11%. Microsoft uses the name ReadyDrive to describe the software side of this technology  (Sony VGP-BPL9 battery)  .

While hybrid drives are not required for Vista Premium certification of laptops, some confusion arose as to whether such drives would be mandatory.

The hybrid drive command interface will be standardized in the new revision 8 of the ATA standard  (Sony VGP-BPS13B/B battery)  .

In 2010 Seagate released the Momentus XT, which uses adaptive memory for its SSD portion, which is not reliant on driver support from the operating system. This removes the need for a special operating system, and the speed benefits can be used by any OS Sony VGP-BPL15 battery .

Claimed benefits

Manufacturers claim several benefits of the hybrid drive over standard hard drives, especially for use in notebook computers. Samsung claims the chief benefits are speed of data access and consequent faster computer boot process,decreased power consumption, and improved reliability  (Dell Inspiron E1505 battery)

Decreased power consumption and heat generation

Because the platters do not need to spin as much, power consumed by the hard drive and dissipated as heat is less than non-hybrid drives. For mobile computers this extends battery life between recharging  Dell Latitude E6400 battery .

Faster boot time, startup from hibernation

Using data in the flash cache, which has good performance for reading data, computers can quickly resume from hibernation (HP Pavilion dv6000 Battery)   .

Decreased noise

The drives are silent when the motor is not running, and the fan can run slower or less frequently (SONY VAIO VGN-FZ Battery) .

Improved reliability

Head crashes due to impact to the computer while the platters are running are less likely SONY VAIO VGN-FZ18 Battery .

Improved performance

Writing to and reading from solid-state memory is faster than a hard drive (with the exception of small writes; see below). While the conventional volatile RAM cache of a normal disk drive is faster than flash memory, data is written to the platters relatively quickly and frequently to minimise the risk of data loss if power is lost   SONY VAIO VGN-FZ180E Battery .

Claimed drawbacks

There are some inherent drawbacks to the use of hybrid drives:

Lower performance (access time) for non-cached data

If the data being accessed is not in the cache and the drive has spun down, access time will be greatly increased since the platters will need to spin-up   SONY VAIO VGN-FZ220E Battery .

This is however not the case with the Seagate Momentus XT.

Lower performance for small disk writes

Flash memory is significantly slower for writing small data, an effect that is amplified by use of journaling file systems SONY VAIO VGN-FZ340E Battery .

Slightly Increased cost

Hybrid hard drives are currently slightly more expensive than their non-hybrid counterparts, because of the higher cost of flash memory.

Reduced lifetime

A hard drive, once spinning, suffers almost no wear  SONY VAIO VGN-FZ430E Battery .

A significant proportion of wear arises during the spin-up and spin-down processes. Indeed, the number of spin-ups is often given as the indication of the lifetime of a hard drive.

Flash memory allows far fewer write cycles than a hard disk  SONY VAIO VGN-FZ460E Battery .

Increased perceived noise production

A hybrid hard drive, spinning up and down, may make drive noise more noticeable, especially with varying usage conditions (i.e., fans and hard drive spinning up on usage)  SONY VAIO VGN-FZ480E Battery .

Increased power usage with spin-ups

A hybrid drive requires spin-up and spin-down more often than a normal hard drive, which is often spinning constantly. Hard drives also draw more power during spin-up    SONY VAIO VGN-FZ4000 Battery .

Lower recoverability

Hybrid hard drives, based on storage to both a flash component and a hard drive component, and bound to use by a specific OS (i.e., Windows Vista), cannot be recovered after failure using classic hard drive recovery services     SONY VAIO VGN-FZ31E Battery .

Software implementation

Windows Vista and Windows 7 natively support the use of hybrid drives (ReadyDrive).

Hybrid drives may also be implemented in software, using other memory instead of a buffer built into the hard drive  SONY VAIO VGN-FZ31B Battery .

Examples of such systems include the SuperCache caching software (implements hybrid RAM drive), and Windows ReadyBoost, which uses separate flash memory and hard disk to make a hybrid drive. Performance of the combined drive may be affected by the speed of the CPU and speed of the separate memory used, in addition to the speed of the hard drive interface  SONY VAIO VGN-FZ31J Battery .

The primary benefits of a hybrid drive may be created from a separate HDD and Flash memory device, managed by software, such as ReadyBoost in Windows   SONY VAIO VGN-FZ31M Battery .

Hybrid RAM Disk

The hybrid RAM disk uses a large buffer of volatile SDRAM memory with battery backup instead of flash memory to cache hard disk data during normal use. The buffer reduces time and energy spent accessing the hard disk. If the RAM cache needs to be filled at startup, hybrid RAM disks may not speed the start-up process as much as flash based hybrid disks  SONY VAIO VGN-FZ31Z Battery .

Battery backup allows data to be written to permanent storage when the device is shut down, and may allow data retention in RAM for limited periods.

Frequently accessed data is stored in DRAM, while all the data is stored in hard disk  SONY VAIO VGN-FZ38M Battery .

As a result, the hard disk only needs to be accessed when the processor requests data that is not frequently used.

Hybrid RAM disks are claimed to offer significantly faster read-write speeds compared to standard hard disks.

Some RAM based SSDs may be used in combination with a hard disk to create a hybrid RAM disk  SONY VGP-BPS8 Battery .

When data is written to memory, the corresponding block in memory is marked as dirty, and all dirty blocks can be flushed to the actual hard drive based on the following criteria: Time (e.g., every 10 seconds, flush all dirty data); Threshold (when the ratio of dirty data to SSD size exceeds some predetermined value, flush the dirty data); Loss of power/computer shutdown  SONY VGP-BPS13 Battery .

Disk storage or disc storage is a general category of storage mechanisms, in which data are digitally recorded by various electronic, magnetic, optical, or mechanical methods on a surface layer deposited of one or more planar, round and rotating plattersSONY VGP-BPS13/S Battery .

A disk drive is a device implementing such a storage mechanism with fixed or removable media; with removable media the device is usually distinguished from the media as in compact disc drive and the compact disc. Notable types are the hard disk drive (which contain a non-removable disc), the floppy disk drive and its removable floppy disk, various optical disc drives and associated mediaSONY VGP-BPS13A/B Battery .

Background

Musical and audio information was originally recorded by analog methods (see Sound recording and reproduction). Similarly the first video disc used analog recording. Analog recording has been mostly replaced by digital optical technology where the data is recorded in a digital format as optical information  SONY VGP-BPS13B/B Battery .

The first commercial disk storage device, that is the first commercial digital disk storage device, was the IBM RAMAC 350 shipped in 1956 as a part of theIBM 305 RAMAC computing system. Disk storage is now used in both computer storage and consumer electronic storage (e.g., audio CD and video DVD)  SONY VGP-BPS13A/S Battery .

The random-access, low-density storage of disks was developed to complement the already used sequential-access high-density storage provided bymagnetic tape. Vigorous innovation in disk storage technology, coupled with less vigorous innovation in tape storage  SONY VGP-BPS13AS Battery ,

has reduced the density and cost per bit gap between disk and tape, reducing the importance of tape as a complement to disk.

Today disk storage devices typically have a single head that moves across a disk surface; earlier there were fixed head devices with multiple heads per surface but today they are no longer being manufactured  Dell Inspiron 1320n Battery .

Movable head devices store more data per sensor and usually more per area of the medium. Fixed head devices avoid the seek time, while the head moves to the data.

Access methods

Disk drives are block storage devices  Dell Inspiron 1464 Battery .

Each disk is divided into logical blocks (collection of sectors). Blocks are addressed using their logical block addresses (LBA). Read from or writing to disk happens at the granularity of blocks.

Originally the disk capacity was quite low and has been improved in one of several ways   Dell Inspiron 1564 Battery .

Improvements in mechanical design and manufacture allowed smaller and more accurate heads, meaning that more tracks could be used on each of the platters. Advancements in data compression methods created more information in each of the individual sectors, and this was instrumental in allowing drives to store smaller units of data  Dell Inspiron 1764 Battery .

sectors of data, the smallest unit stored, were reduced and so less wasted space was created.

The drive stores data onto cylinders, heads and sectors. The sectors unit is the smallest size of data to be stored in a Hard Disk Drive and each file will have many sectors units assigned to it  Dell Studio 1450 Battery .

The smallest entity in a CD is called a frame, which consists of 33 bytes and contains six complete 16-bit stereo samples (two bytes × two channels × six samples = 24 bytes)  . The other nine bytes consist of eight CIRC error-correction bytes and one subcode byte used for control and display  Dell Studio 1457 Battery .

The information is sent from the computer processor to the BIOS into a chip controlling the data transfer. This is then sent out to the hard drive via a multi-wire connector. Once the data is received onto the circuit board of the drive, it is translated and compressed into a format that the individual drive can use to store onto the disk itself  Dell Latitude D610 Battery .

The data is then passed to a chip on the circuit board that controls the access to the drive. The drive is divided into sectors of data stored onto one of the sides of one of the internal disks. In the picture opposite we have two disk, this gives us 4 sides   Toshiba NB100 Battery .

The hardware on the drive tells the actuator arm where it is to go for the relevant track and the compressed information is then sent down to the head which changes the physical properties, optically or magnetically for example, of each byte on the drive, thus storing the information   Toshiba Satellite M65 battery .

A file is not stored in a linear manner, rather, it is held in the best way for quickest retrieval.

Mechanically, there are usually two types of motion: the constant rate rotation, which passes the data of a track sequentially under a read head, and the radial (side-to-side) head motion or seek, which selects the track  Toshiba Satellite M60 battery .

Rotation is faster than seek, so the logical blocks are related in simple ways to the physical tracks.

Interfaces

Disk drive interface is the mechanism/protocol of communication between the rest of the system and the disk drive itself  Dell Latitude D830 Battery .

Different interface types include SCSI and SAS for enterprise or high-end disks,ATA (PATA), SATA for desktop disks.

Basic terminology

  • Rotation - how the disks spin. Two techniques are common   Dell Latitude D620 Battery :
    • Constant angular velocity (CAV) keeps the disk spinning at a fixed rate, measured in revolutions per minute (RPM). This means the heads cover more distance per unit of time on the outer tracks than on the inner tracks. This method is typical with computer hard drives   Dell Inspiron Mini 10 Battery .
    • Constant linear velocity (CLV) keeps the distance covered by the heads per unit time fixed. Thus the disk has to slow down as the arm moves to the outer tracks. This method is typical for CDdrives.
  • Sector - an area of disk enclosed within a given central angle (a pie piece)  Sony VGN-FW11S Battery
  • Platter - an individual recording surface. In a hard disk drive we tend to find a set of platters and developments in optical technology have led to multiple recording layers on a single DVD's.
  • Low level formatting - establishing the tracks and sectors   Sony VGN-FW11M Battery .
  • Track - the circle of recorded data on a single recording surface for a single arm position.
  • Head - the device that reads and writes the information - magnetic or optical - on the disk surface.
  • Arm - the mechanical assembly that supports the head as it moves in and out.
  • Seek time - average time needed to move the head to a new position(specific track)  Sony VGN-FW139E/H battery .
  • Rotational delay - average time, once the arm is on the right track, before a head is over a desired sector.
  • Interleave - the spacing between sectors. Sequential sectors were spaced on the media to enable the next sector to be in the correct position under the head once the host was ready to read it   Dell Latitude E5400 Battery .
  • At an interleave factor of 3:1, three full rotations would be required to read an entire track. Due to technological advances almost all hard disk drives since Compaq and Western Digital defined the AT Attachment standard have used an interleave factor of 1:1. Floppy disks are still usually interleaved  Dell Latitude E4200 Battery .

Blu-ray Disc (official abbreviation BD) is an optical disc storage medium designed to supersede the DVD format. The format defines as its standard physical media a 12 cm (same as DVDs and CDs), 25 GB per-layer optical disc, with dual layer discs (50 GB) the norm for feature-length video discs and additional layers possible later  Dell Vostro A840 Battery .

The name Blu-ray Disc refers to the blue laser used to read the disc, which allows for six times more storage than on a DVD. The term Blu was used because blue is commonly used in English and therefore not registrable as a trademark  Dell Inspiron 300M Battery .

Blu-ray Disc was developed by the Blu-ray Disc Association, a group representing makers of consumer electronics, computer hardware, and motion pictures. As of June 2009, more than 1,500 Blu-ray Disc titles were available in Australia and the United Kingdom, with 2,500 in the United States and Canada   Dell Studio 1737 battery .

In Japan as of July 2010 more than 3,300 titles were released.

During the high definition optical disc format war, Blu-ray Disc competed with the HD DVD format. Toshiba, the main company that supported HD DVD, conceded in February 2008, releasing their own Blu-ray Disc player in late 2009  Dell Inspiron E1505 battery .

History

Commercial HDTV sets began to appear in the consumer market around 1998, but there was no commonly accepted, inexpensive way to record or play HD content   Dell RM791 battery .

In fact, there was no medium with the storage required to accommodate full-length video encoded with HD codecs, except for JVC's Digital VHS and Sony's HDCAM. Nevertheless, it was well known that using lasers with shorter wavelengths would enable optical storage with higher density.Shuji Nakamura invented the practical blue laser diode  Dell XPS M1530 battery ;

it was a sensation among the computer storage-medium community, although a lengthy patent lawsuit delayed commercial introduction.

Origins

Sony/Philips started two projects applying the new diodes  Dell XPS M2010 battery :

UDO (Ultra Density Optical), and DVR Blue (together with Pioneer), a format of rewritable discs that would eventually become Blu-ray Disc (more specifically, BD-RE). The core technologies of the formats are similar.

The first DVR Blue prototypes were unveiled at the CEATEC exhibition in October 2000  Acer Aspire One battery .

A trademark for the "Blue Disc" logo was filed February 9, 2001. On February 19, 2002, the project was officially announced as Blu-ray Disc, and Blu-ray Disc Founders was founded by the nine initial members.

The first consumer device arrived in stores on April 10, 2003  Toshiba Satellite P10 Battery :

the Sony BDZ-S77, a US$3,800 BD-RE recorder that was made available only in Japan. But there was no standard for prerecorded video, and no movies were released for this player  SONY VGN-FZ210CE Battery .

Hollywood studios insisted that players be equipped with Digital Rights Management before they would release movies for the new format, and they wanted a new DRM system that would be more secure than the failed Content Scramble System (CSS) used on DVDs  Dell Precision M70 Battery .

On October 4, 2004, the name "Blu-ray Disc Founders" was officially changed to the Blu-ray Disc Association (BDA), and 20th Century Fox joined the BDA's Board of Directors.

The Blu-ray Disc physical specifications were completed in 2004  Toshiba Satellite L305 Battery .

In January 2005, TDK announced that they had developed a hard coating polymer for Blu-ray Discs. Cartridges, originally used for scratch protection, were no longer necessary and were scrapped.

The BD-ROM specifications were finalized in early 2006   Toshiba Satellite T4900 Battery .

AACS LA, a consortium founded in 2004, had been developing the DRM platform that could be used to securely distribute movies to consumers. However, the final AACS standard was delayed, and then delayed again when an important member of the Blu-ray Disc group voiced concerns   Toshiba PA3399U-2BRS battery .

At the request of the initial hardware manufacturers, including Toshiba, Pioneer, and Samsung, an interim standard was published that did not include some features, such as managed copy.

Launch and sales developments

The first BD-ROM players were shipped in mid-June 2006, though HD DVD players beat them to market by a few months  Toshiba Satellite A200 Battery .

The first Blu-ray Disc titles were released on June 20, 2006: 50 First Dates, The Fifth Element, Hitch, House of Flying Daggers, Underworld: Evolution, xXx(all Sony), and MGM's The Terminator. The earliest releases used MPEG-2 video compression, the same method used on standard DVDs        Toshiba Satellite 1200 Battery .

The first releases using the newer VC-1 and AVC codecs were introduced in September 2006. The first movies using 50 GB dual-layer discs were introduced in October 2006. The first audio-only release was made in March 2008.

The first mass-market Blu-ray Disc rewritable drive for the PC was the BWU-100A, released by Sony on July 18, 2006  Toshiba Satellite M300 Battery .

It recorded both single and dual-layer BD-Rs as well as BD-REs and had a suggested retail price of US $699.

Competition from HD DVD

The DVD Forum, chaired by Toshiba, was split over whether to develop the more expensive blue laser technology  Sony Vaio PCG-5G2L Battery .

In March 2002, the forum approved a proposal endorsed by Warner Bros. and other motion picture studios that involved compressing HD content onto dual-layer standard DVD-9 discs. In spite of this decision, however, the DVD Forum's Steering Committee announced in April that it was pursuing its own blue-laser high-definition solution  Sony Vaio PCG-5G3L Battery .

In August, Toshiba and NEC announced their competing standard, Advanced Optical Disc.It was finally adopted by the DVD Forum and renamed HD DVD the next year, after being voted down twice by DVD Forum members who were also Blu-ray Disc Association members—a situation that drew preliminary investigations by the U.S. Department of Justice  Sony Vaio PCG-5J1L Battery .

HD DVD had a head start in the high-definition video market, as Blu-ray Disc sales were slow to gain market share. The first Blu-ray Disc player was perceived as expensive and buggy, and there were few titles available.

The appearance of the Sony PlayStation 3, which contained a Blu-ray Disc player for primary storage, helped turn the tide  Sony Vaio PCG-5K2L Battery .

Sony also ran a more thorough and influential marketing campaign for the format. 2006 also saw the launch of AVCHD camcorders, whose recordings can be played back on many Blu-ray Disc players without re-encoding, but not on HD DVD players  Sony Vaio PCG-5J2L Battery .

By January 2007, Blu-ray Discs had outsold HD DVDs, and during the first three quarters of 2007, BD outsold HD DVDs by about two to one. At CES 2007, Warner proposed Total Hi Def—a hybrid disc containing Blu-ray on one side and HD DVD on the other, but it was never released  Sony Vaio PCG-5K1L Battery .

In a June 28, 2007 press release, Twentieth Century Fox cited Blu-ray Disc's adoption of the BD+ anticopying system as key to their decision to support the Blu-ray Disc format.

In February 2008, Toshiba withdrew its support for the HD DVD format, conceding victory to Blu-ray Disc  Sony Vaio PCG-5L1L Battery .

End of the format war and future prospects

On January 4, 2008, a day before CES 2008, Warner Bros. (the only major studio still releasing movies in both HD DVD and Blu-ray Disc format) announced that it would release only in Blu-ray Disc after May 2008  Sony Vaio PCG-6S2L Battery .

This effectively included other studios that came under the Warner umbrella, such asNew Line Cinema and HBO—though in Europe, HBO distribution partner, the BBC, announced it would, while keeping an eye on market forces, continue to release product on both formats   Sony Vaio PCG-6S3L Battery .

This led to a chain reaction in the industry, with major U.S. retailers such as Best Buy, Wal-Mart, and Circuit City and Canadian chains such as Future Shop dropping HD DVD in their stores. A former major European retailer, Woolworths, dropped HD DVD from its inventory   Sony Vaio PCG-6V1L Battery .

Netflix and Blockbuster—major DVD rental companies—said they would no longer carry HD DVDs. Following these new developments, on February 19, 2008, Toshiba announced it would end production of HD DVD devices,allowing Blu-ray Disc to become the industry standard for high-density optical discs   Sony Vaio PCG-6W1L Battery .

Universal Studios, the sole major movie studio to back HD DVD since its inception, said shortly after Toshiba's announcement, "While Universal values the close partnership we have shared with Toshiba, it is time to turn our focus to releasing new and catalog titles on Blu-ray Disc  Sony Vaio PCG-6W2L Battery ."

Paramount Studios, which started releasing movies only in HD DVD format during late 2007, also said it would start releasing in Blu-ray Disc. Both studios announced initial Blu-ray lineups in May 2008. With this, all major Hollywood studios now support Blu-ray  Sony Vaio PCG-6W3L Battery .

According to Adams Media Research, high-definition software sales in the US were slower in the first two years than DVD software sales. 16.3 million DVD software units were sold in the first two years (1997–98) compared to 8.3 million high-definition software units (2006–07) Sony Vaio PCG-7111L Battery .

One reason given for this difference was the smaller marketplace (26.5 million HDTVs in 2007 compared to 100 million SDTVs in 1998). Former HD DVD supporter Microsoft has stated that they are not planning to make a Blu-ray Disc drive for the Xbox 360.

Blu-ray Disc began making serious strides as soon as the format war ended  Sony Vaio PCG-7112L Battery .

Nielsen VideoScan sales numbers showed that with some titles, such as 20th Century Fox's Hitman, up to 14% of total disc sales were from Blu-ray, although the average for the first half of the year was around 5%. Shortly after the format war ended, a study by The NPD Group found that awareness of Blu-ray Disc had reached 60% of U.S. households  Sony Vaio PCG-7113L Battery .

In December 2008, the Blu-ray Disc of The Dark Knight sold 600,000 copies on the first day of its launch in the United States, Canada, and the United Kingdom. A week after launch, The Dark Knight BD had sold over 1.7 million copies worldwide, making it the first Blu-ray Disc title to sell over a million copies in the first week of release  Sony Vaio PCG-7133L Battery .

According to Singulus Technologies AG, Blu-ray is being adopted faster than the DVD format was at a similar period in its development. This conclusion was based on the fact that Singulus Technologies has received orders for 21 Blu-ray dual-layer machines during the first quarter of 2008, while 17 DVD machines of this type were made in the same period in 1997  Sony Vaio PCG-7Z2L Battery .

And the other key equipment supplier for optical disc Anwell Technologies Limited had shipped its Blu-ray Disc production equipment to Frankfurt for the largest trade show in the world — MEDIA-TECH Expo in May 2008 and they received new order for the Blu-ray production line also   Sony Vaio PCG-8Y1L Battery .

According to GfK Retail and Technology, in the first week of November 2008, sales of Blu-ray recorders surpassed DVD recorders in Japan. According to the Digital Entertainment Group, the total number of Blu-ray Disc playback devices (both set-top box and game console) had reached 17.3 millions by the end of 2009  Sony Vaio PCG-8Y2L Battery .

According to Swicker & Associates, Blu-ray Disc software sales in the United States and Canada were 1.2 million in 2006, 19.2 million in 2007, 82.4 million in 2008, and 177.2 million in 2009.Some commentators have suggested that renting Blu-ray will play a vital part in keeping the technology affordable while allowing it to move forward  Sony Vaio PCG-8Z1L Battery .

In an effort to increase sales, studios are releasing movies in combo packs with Blu-ray Discs and DVDs as well as "digital copies" which can be played on computers and iPods. Some are released on "flipper" discs with Blu-ray on one side and DVD on the other. Other strategies are to release movies with the special features only on Blu-ray Discs and none on DVDs  Sony Vaio PCG-8Z2L Battery.

Blu-ray faces competition from video on demand and from new technologies that allow access to movies on any format or device, such as Digital Entertainment Content Ecosystem or Disney'sKeychest  Sony VAIO PCG-5G2L Battery .

Physical media

Laser and optics

While a DVD uses a 650-nanometer red laser, Blu-ray Disc uses a 405 nm "blue" laser. This shorter wavelength allows for over five times more data storage per layer than allowed by a DVD. Note that even though the laser is called "blue", its color is actually in the violet range   Sony VAIO PCG-5G3L Battery .

The diodes are GaN (gallium nitride) lasers that produce 405 nm light directly, that is, without frequency doubling or other nonlinear optical mechanisms. Conventional DVDs and CDs use red and near-infrared lasers, at 650 nm and 780 nm, respectively  Sony VAIO PCG-5J1L Battery .

The minimum "spot size" on which a laser can be focused is limited by diffraction, and depends on the wavelength of the light and the numerical aperture of the lens used to focus it. By decreasing the wavelength, increasing the numerical aperture from 0.60 to 0.85   Sony VAIO PCG-5K2L Battery ,

and making the cover layer thinner to avoid unwanted optical effects, the laser beam can be focused to a smaller spot, which effectively allows more information to be stored in the same area.

For Blu-ray Disc, the spot size is 580 nm. In addition to the optical improvements, Blu-ray Discs feature improvements in data encoding that further increase the capacity Sony VAIO PCG-5J2L Battery .

(See Compact Disc for information on optical discs' physical structure.)

Hard-coating technology

Since the Blu-ray Disc data layer is closer to the surface of the disc compared to the DVD standard, it was at first more vulnerable to scratches. The first discs were housed in cartridges for protection, resembling Professional Discs introduced by Sony in 2003 Sony VAIO PCG-5K1L Battery .

Using a cartridge would increase the price of an already expensive medium, so hard-coating of the pickup surface was chosen instead. TDK was the first company to develop a working scratch-protection coating for Blu-ray Discs. It was named Durabis. In addition, both Sony and Panasonic's replication methods include proprietary hard-coat technologies  Sony VAIO PCG-5L1L Battery .

Sony's rewritable media are spin-coated, using a scratch-resistant and antistatic coating. Verbatim'srecordable and rewritable Blu-ray Discs use their own proprietary hard-coat technology, called ScratchGuard.

The Blu-ray Disc specification requires the testing of resistance to scratches by mechanical abrasion  Sony VAIO PCG-6S2L Battery .

In contrast, DVD media are not required to be scratch-resistant, but since development of the technology, some companies, such as Verbatim, implemented hard-coating for more expensive lineups of recordable DVDs  Sony VAIO PCG-6S3L Battery .

Recording speed

Variants

Mini Blu-ray Disc

The "Mini Blu-ray Disc" (also, "Mini-BD" and "Mini Blu-ray") is a compact 8 cm (~3 in)-diameter variant of the Blu-ray Disc that can store approximately 7.5 GB of data. It is similar in concept to theMiniDVD and MiniCD. Recordable (BD-R) and rewritable (BD-RE) versions of Mini Blu-ray Disc have been developed specifically for compact camcorders and other compact recording devices Sony VAIO PCG-6V1L Battery .

Blu-ray Disc recordable

"Blu-ray Disc recordable" refers to two optical disc formats that can be recorded with an optical disc recorder. BD-Rs can be written to once, whereas BD-REs can be erased and re-recorded multiple times. The current practical maximum speed for Blu-ray Discs is about 12×  Sony VAIO PCG-6W1L Battery .

Higher speeds of rotation (10,000+ rpm) cause too much wobble for the discs to be read properly, as with the 20× and 52× maximum speeds, respectively, of standard DVDs and CDs.

Since September 2007, BD-RE is also available in the smaller 8 cm Mini Blu-ray Disc size  Sony VAIO PCG-6W2L Battery .

On September 18, 2007, Pioneer and Mitsubishi codeveloped BD-R LTH ("Low to High" in groove recording), which features an organic dye recording layer that can be manufactured by modifying existing CD-R and DVD-R production equipment, significantly reducing manufacturing costs  Sony VAIO PCG-6W3L Battery .

In February 2008, Taiyo Yuden, Mitsubishi, and Maxell released the first BD-R LTH Discs,and in March 2008, Sony's PlayStation 3 gained official support for BD-R LTH Discs with the 2.20 firmware update.In May 2009 Verbatim/Mitsubishi announced the industry's first 6X BD-R LTH media, which allows recording a 25 GB disc in about 16 minutes  Sony VAIO PCG-7111L Battery .

Unlike the previous releases of 120 mm optical discs (i.e., CDs and standard DVDs), Blu-ray recorders hit the market almost simultaneously with Blu-ray's debut.

BD9 and BD5

The BD9 format was proposed to the Blu-ray Disc Association by Warner Home Video as a cost-effective alternative to the 25/50 GB BD-ROM discs   Sony VAIO PCG-7112L Battery .

The format was supposed to use the same codecs and program structure as Blu-ray Disc video, but recorded onto less expensive 8.5 GB dual-layer DVD. This red-laser media could be manufactured on existing DVD production lines with lower costs of production than the 25/50 GB Blu-ray media   Sony VAIO PCG-7113L Battery .

Usage of BD9 for releasing content on "pressed" discs has never caught on. After the end of the format war, major producers ramped up the production of Blu-ray Discs and lowered their prices to the level of DVDs. On the other hand, the idea of using inexpensive DVD media became popular among individual users     Sony VAIO PCG-7133L Battery .

A lower-capacity version of this format that uses single-layer 4.7 GB DVDs has been unofficially called BD5. Both formats are being used by individuals for recording high definition content in Blu-ray format onto recordable DVD media.

Despite the fact that the BD9 format has been adopted as part of the BD-ROM basic format  Sony VAIO PCG-7Z1L Battery ,

none of the existing Blu-ray player models support it explicitly. As such, the discs recorded in BD9 and BD5 formats are not guaranteed to play on standard Blu-ray Disc players.

AVCHD and AVCREC also use inexpensive media like DVDs, but unlike BD9 and BD5 these formats have limited interactivity, codec types, and data rates    Sony VAIO PCG-7Z2L Battery .

BDXL

The BDXL format supports 100GB and 128GB write-once discs  and 100GB rewritable discs for commercial applications. It was defined in June 2010.

BD-R 3.0 Format Specification (BDXL) defined a multi-layered disc recordable in BDAV format with the speed of 2X and 4X, capable of 100/128GB and usage of UDF2.5/2.6       Sony VAIO PCG-8Y1L Battery .

BD-RE 4.0 Format Specification (BDXL) defined a multi-layered disc rewritable in BDAV with the speed of 2X and 4X, capable of 100GB and usage of UDF2.5 as file system.

IH-BD

The IH-BD (Intra-Hybrid Blu-ray) format includes a 25GB write-once layer (BD-R) and a 25GB read-only layer (BD-ROM), designed to work with existing Blu-ray Discs   Sony VAIO PCG-8Y2L Battery .

Software Standards

Filesystem

Blu-ray Disc specifies the use of Universal Disk Format (UDF) 2.50 as a convergent friendly format for both PC and consumer electronics environments. It is used in latest specifications of BD-ROM, BD-RE and BD-R  Sony VAIO PCG-8Z1L Battery .

In the first BD-RE specification (defined in 2002), the BDFS (Blu-ray Disc File System) was used. The BD-RE 1.0 specification was defined mainly for broadcast recording of High Definition TV. The BDFS was replaced by UDF 2.50 in the second BD-RE specification in 2005, in order to enable interoperability among consumer electronics Blu-ray recorders and personal computer systems  Sony VAIO PCG-8Z2L Battery .

This enabled PC recording and playback of BD-RE.BD-R can use UDF 2.50/2.60.

The Blu-ray Disc application (BDAV application) for recording of digital broadcasting has been developed as System Description Blu-ray Rewritable Disc Format part 3 Audio Visual Basic Specifications (Sony VGP-BPS21 Battery) .

The requirements related with file system have been specified in System Description Blu-ray Rewritable Disc Format part 2 File System Specifications version 1.0 (BDFS).

Initially, the BD-RE version 1.0 (BDFS) was specifically developed for recording of digital broadcasting using the Blu-ray Disc application (BDAV application)   Sony VGP-BPS21A Battery .

To support UDF, these requirements are superseded by the Blu-ray Rewritable Disc File System Specifications version 2.0 (UDF) (a.k.a. RE 2.0) and Blu-ray Recordable Disc File System Specifications version 1.0 (UDF) (a.k.a. R 1.0). Additionally, a new application format, BDMV (System Description Blu-ray Disc Prerecorded Format part 3 Audio Visual Basic Specifications) for High Definition Content Distribution was developed for BD-ROM   Sony VGP-BPS21B Battery .

The only file system developed for BDMV is the System Description Blu-ray Read-Only Disc Format part 2 File System Specifications version 1.0 (UDF) which defines the requirements for UDF 2.50.

Directory and file structure

All BD-ROM application files are stored under a “BDMV” directory  Sony VGP-BPS21/S Battery .

  • BDMV directory: contains the PLAYLIST, CLIPINF, STREAM, AUXDATA and BACKUP directories.
    • PLAYLIST directory: contains the Database files for Movie PlayLists.
      • xxxxx.mpls files: store information corresponding to Movie PlayLists. One file is created for each Movie PlayList  Sony VGP-BPS21A/B Battery .
      • The filenames of these files are in the form “xxxxx.mpls”, where “xxxxx” is a 5-digit number corresponding to the Movie PlayList.
    • CLIPINF directory: contains the Database files for Clips.
      • zzzzz.clpi files: store Clip information associated with a Clip AV stream file. The filenames of these files are in the form “zzzzz.clpi”, where “zzzzz” is a 5-digit number corresponding to the Clip  Sony Vaio PCG-5G2L Battery .
    • STREAM directory: contains AV stream files.
      • zzzzz.m2ts file: contains a BDAV MPEG-2 transport stream. The names of these files are in the form “zzzzz.m2ts”, where “zzzzz” is a 5-digit number corresponding to the Clip. The same 5-digit number “zzzzz” is used for an AV stream file and its associated Clip information file  Sony Vaio PCG-5G3L Battery .
      • SSIF directory: If used, Stereoscopic Interleaved files shall be placed under this directory.
        • zzzzz.ssif file: is a Stereoscopic Interleaved file that is composed from two BDAV MPEG-2 transport streams. Both of the streams include an MPEG-4 MVC view video stream for left eye or right eye respectively  Sony Vaio PCG-5J1L Battery .
        • This file is used only when 3D video is played back. The 5-digit number “zzzzz” is the same as the number used for the AV stream file “zzzzz.m2ts” that includes the MPEG-4 MVC Base view video stream.
    • AUXDATA directory: contains Sound data files and Font files  Sony Vaio PCG-5K2L Battery .
      • sound.bdmv file: stores data relating to one or more sounds associated with HDMV Interactive Graphic streams applications. This file may or may not exist under the AUXDATA directory. If it exists, there shall be only one sound.bdmv file  Sony Vaio PCG-5J2L Battery .
      • aaaaa.otf file: stores the font information associated with Text subtitle applications. The names of these files are in the form “aaaaa.otf”, where “aaaaa” is a 5-digit number corresponding to the Font  Sony Vaio PCG-5K1L Battery .
    • BACKUP directory: contains copies of the "index.bdmv” file, the “MovieObject.bdmv” file, all the files in the PLAYLIST directory and all files in the CLIPINF directory  Sony Vaio PCG-5L1L Battery .
    • index.bdmv file: stores information describing the contents of the BDMV directory. There is only one index.bdmv file under the BDMV directory   Sony Vaio PCG-6S2L Battery .
    • MovieObject.bdmv file: stores information for one or more Movie Objects. There is only one MovieObject.bdmv under the BDMV directory     Sony Vaio PCG-6S3L Battery .

Media format

Container format

Audio, video and other streams are multiplexed and stored on Blu-ray Discs in a container format based on the MPEG transport stream. It is also known as BDAV MPEG-2 transport stream and can use filename extension .m2ts  Sony Vaio PCG-6V1L Battery .

Blu-ray Disc titles authored with menu support are in the BDMV (Blu-ray Disc Movie) format and contain audio, video, and other streams in BDAV container. There is also the BDAV (Blu-ray Disc Audio/Visual) format, the consumer oriented alternative to the BDMV format used for movie releases   Sony Vaio PCG-6W1L Battery .

The BDAV format is used on BD-REs and BD-Rs for audio/video recording. BDMV format was later defined also for BD-RE and BD-R (in September 2006, in the third revision of BD-RE specification and second revision of BD-R specification). Blu-ray Disc employs the MPEG transport stream recording method   Sony Vaio PCG-6W2L Battery .

That enables transport streams of digital broadcasts to be recorded as they are without altering the format. It also enables flexible editing of a digital broadcast that is recorded as is and where the data can be edited just by rewriting the playback stream. Although it is quite natural, a function for high-speed and easy-to use retrieval is built in  Sony Vaio PCG-6W3L Battery .

Blu-ray Disc Video use MPEG transport streams, compared to DVD's MPEG program streams. This allows multiple video programs to be stored in the same file so they can be played back simultaneously (e.g., with "Picture in picture" effect)   Sony Vaio PCG-7111L Battery .

Codecs

The BD-ROM specification mandates certain codec compatibilities for both hardware decoders (players) and movie software (content)  Sony Vaio PCG-7112L Battery .

Video

High-definition video may be stored on BD-ROMs with up to 1920×1080 pixel resolution at up to 59.94 fields per second, if interlaced. Alternatively, progressive scan can go up to 1920×1080 pixel resolution at 24 frames per second, or up to 1280x720 at up to 59.94 frames per second  Sony Vaio PCG-7113L Battery :

For video, all players are required to support MPEG-2 Part 2, H.264/MPEG-4 AVC, and SMPTE VC-1. MPEG-2 is the codec used on regular DVDs, which allows backwards compatibility. MPEG-4 AVC was developed by MPEG, Sony, and VCEG. VC-1 is a codec that was mainly developed by Microsoft       Sony Vaio PCG-7133L Battery .

BD-ROM titles with video must store video using one of the three mandatory codecs; multiple codecs on a single title are allowed.

The choice of codecs affects the producer's licensing/royalty costs as well as the title's maximum run time, due to differences in compression efficiency       Sony Vaio PCG-7Z1L Battery .

Discs encoded in MPEG-2 video typically limit content producers to around two hours of high-definition content on a single-layer (25 GB) BD-ROM. The more-advanced video codecs (VC-1 and MPEG-4 AVC) typically achieve a video run time twice that of MPEG-2, with comparable quality      Sony Vaio PCG-7Z2L Battery .

MPEG-2 was used by many studios (including Paramount Pictures, which initially used the VC-1 codec for HD DVD releases) for the first series of Blu-ray Discs, which were launched throughout 2006.Modern releases are now often encoded in either MPEG-4 AVC or VC-1, allowing film studios to place all content on one disc, reducing costs and improving ease of use  Sony Vaio PCG-8Y1L Battery .

Using these codecs also frees a lot of space for storage of bonus content in HD (1080i/p), as opposed to the SD (480i/p) typically used for most titles. Some studios, such as Warner Bros., have released bonus content on discs encoded in a different codec than the main feature title    Sony Vaio PCG-8Y2L Battery .

For example, the Blu-ray Disc release of Superman Returns uses VC-1 for the feature film and MPEG-2 for bonus content. Today, Warner and other studios

typically provide bonus content in the video codec that matches the feature.

Audio

For audio, BD-ROM players are required to support Dolby Digital (AC-3), DTS, and linear PCM   Sony Vaio PCG-8Z1L Battery .

Players may optionally support Dolby Digital Plus and DTS-HD High Resolution Audio as well aslossless formats Dolby TrueHD and DTS-HD Master Audio.[94] BD-ROM titles must use one of the mandatory schemes for the primary soundtrack. A secondary audiotrack, if present, may use any of the mandatory or optional codecs       Sony Vaio PCG-8Z2L Battery .

Bit rate

For users recording digital television programming, the recordable Blu-ray Disc standard's initial data rate of 36 Mbit/s is more than adequate to record high-definition broadcasts from any source (IPTV, cable/satellite, or terrestrial)  WD passport essential (500GB/640GB) .

BD Video movies have a maximum data transfer rate of 54 Mbit/s, a maximum AV bitrate of 48 Mbit/s (for both audio and video data), and a maximum video bit rate of 40 Mbit/s. This compares to HD DVD movies, which have a maximum data transfer rate of 36 Mbit/s, a maximum AV bitrate of 30.24 Mbit/s, and a maximum video bitrate of 29.4 Mbit/s  WD passport essential (250GB/320GB).

Application format

  • BDAV or BD-AV (Blu-ray Disc Audio/Visual) – a consumer-oriented Blu-ray video format used for audio/video recording (defined in 2002)
  • BDMV or BD-MV (Blu-ray Disc Movie)  – a Blu-ray video format with menu support commonly used for movie releases
    • BDMV Recording specification – (defined in September 2006 for BD-RE and BD-R)  WD  passport essential SE (750GB/1TB)   .
      • RREF – (Realtime Recording and Editing Format) – a subset of BDMV designed for realtime recording and editing applications

Java software support

At the 2005 JavaOne trade show, it was announced that Sun Microsystems' Java cross-platform software environment would be included in all Blu-ray Disc players as a mandatory part of the standard   WD  passport elite(250GB/320GB) .

Java is used to implement interactive menus on Blu-ray Discs, as opposed to the method used on DVD-video discs. DVDs use pre-rendered MPEG segments and selectable subtitle pictures, which are considerably more primitive and rarely seamless. At the conference   WD passport elite(500GB/640GB) ,

Java creator James Gosling suggested that the inclusion of a Java Virtual Machine, as well as network connectivity in some BD devices, will allow updates to Blu-ray Discs via the Internet, adding content such as additional subtitle languages and promotional features not included on the disc at pressing time    WD  passport studio for Mac(320GB/500GB) .

This Java Version is called BD-J and is a subset of the Globally Executable MHP (GEM) standard; GEM is the worldwide version of the Multimedia Home Platform standard.

Player profiles

The BD-ROM specification defines four Blu-ray Disc player profiles, including an audio-only player profile (BD-Audio) that does not require video decoding or BD-J  WD  passport studio for Mac(500GB/640GB) .

All three of the video-based player profiles (BD-Video) are required to have a full implementation of BD-J, with varying levels of hardware support.

On November 1, 2007, the Grace Period Profile was superseded by Bonus View as the minimum profile for new BD-Video players released to the market       WD  Elements series(250GB/320GB) .

When Blu-ray Disc software not authored with interactive features dependent on Bonus View or BD-Live hardware capabilities is played on Profile 1.0 players, it is able to play the main feature of the disc, but some extra features may not be available or will have limited capability      WD  Elements SE(500GB/640GB) .

BD-Live

The biggest difference between Bonus View and BD-Live is that BD-Live requires the Blu-ray Disc player to have an Internet connection to access Internet-based content. BD-Live features have included automatic firmware updates, checking each time the device is switched on to see if it has been tampered with and report the same   WD Elements SE(750GB/1TB) ,

Internet chats, scheduled chats with the director, Internet games, downloadable featurettes, downloadable quizzes, and downloadable movie trailers. Note that while some Bonus View players may have an Ethernet port, these are used for firmware updates and are not used for Internet-based content      WD  Elements desktop(500GB/640GB) .

In addition, Profile 2.0 also requires more local storage in order to handle this content.

With the exception of the latest players and the PlayStation 3, Profile 1.0 players cannot be upgraded to be Bonus View or BD-Live compliant        WD  Elements desktop(750GB/1TB) .

Region codes

As with the implementation of region codes for DVDs, Blu-ray Disc players sold in a specific geographical region are designed to play only discs authorized by the content provider for that region        WD  Elements desktop(1.5 TB/2TB) .

This is intended to permit content providers (motion picture studios, etc.) the ability to support product differences in content, price, release date, etc., by region. According to the Blu-ray Disc Association, "all Blu-ray Disc players...(and) Blu-ray Disc-equipped computer systems are required to support regional coding  WD  passport essential SE (750GB/1TB)--USB 3.0)    .

" However, "Use of region playback codes is optional for content providers..."Some current estimates suggest 70% of available [movie] Blu-ray Discs from the major studios are region-code-free and can therefore be played on any Blu-ray Disc player, in any region  WD  passport essential (500GB/640GB) .

Movie studios have different region coding policies. Among major U.S. studios, Paramount Pictures and Universal Studios have released all of their titles region-free. Sony Pictures and Warner Bros. have released most of their titles region-free. Lionsgate and Walt Disney Pictures have released a mix of region-free and region-coded titles  WD  passport for Mac(320GB/500GB) .

20th Century Fox and MGM have released most of their titles region-coded.

The Blu-ray Disc region coding scheme divides the world into 3 regions, labeled A, B, and C.

  • Region A includes most North, Central and South American and Southeast Asian countries plus the Republic of China (Taiwan), Hong Kong, Japan and Korea        WD  passport for Mac(640GB/1TB)
  • Region B includes most European, African and southwest Asian countries plus Australia and New Zealand.
  • Region C contains the remaining central and south Asian countries, as well as the People's Republic of China and Russia  My book essential 4 generation  (640GB/1TB) .

In circumvention of region coding restrictions, stand-alone Blu-ray Disc players are sometimes modified by third parties to allow for playback of Blu-ray Discs (and DVDs) with any region code        WD  My book essential 4 generation( 1.5TB/2TB) .

Instructions ('hacks') describing how to reset the Blu-ray region counter of computer player applications to make them multi-region indefinitely are also regularly posted to video enthusiast websites and forums. Unlike DVD region codes, Blu-ray region codes are verified only by the player software, not by the optical drive's firmware  WD  My book elite( 1TB/1.5TB) .

Digital rights management

The Blu-ray Disc format employs several layers of digital rights management (DRM).This has led to extensive criticism of the format by organisations opposed to DRM, such as the Free Software Foundation  WD  My book studio(1TB/2TB) .

HDCP

Blu-ray equipment is encouraged to implement HDCP. Given certain flags in the media streams, a Blu-ray Disc can enforce its reproduction in a lower resolution whenever a full HDCP-compliant link isn't established all the way from the Blu-ray drive to the rendering devices (i.e. display and speakers)  WD  My book essential 4 generation( 1.5TB/2TB) .

AACS

The Advanced Access Content System (AACS) is a standard for content distribution and digital rights management. It was developed by AS Licensing Administrator, LLC (AACS LA), a consortium that includes Disney, Intel, Microsoft, Panasonic, Warner Bros., IBM, Toshiba, and Sony        WD  My book elite(640GB/2TB) .

Since appearing in devices in 2006, several successful attacks have been made on the format. The first known attack relied on the trusted client problem. In addition, decryption keys have been extracted from a weakly protected player (WinDVD). Since keys can be revoked in newer releases       Seagate  expansion portable (320GB/500GB) ,

this is only a temporary attack, and new keys must continually be discovered in order to decrypt the latest discs. This cat-and-mouse game has gone through several cycles.

BD+

BD+ was developed by Cryptography Research Inc. and is based on their concept of Self-Protecting Digital Content  Seagate  expansion (1.5TB/2TB) .

BD+, effectively a small virtual machine embedded in authorized players, allows content providers to include executable programs on Blu-ray Discs. Such programs can:

  • examine the host environment to see if the player has been tampered with. Every licensed playback device manufacturer must provide the BD+ licensing authority with memory footprints that identify their devices  Seagate  Freeagent Desktop (500GB/1TB) .
  • verify that the player's keys have not been changed.
  • execute native code, possibly to patch an otherwise insecure system.
  • transform the audio and video output. Parts of the content will not be viewable without letting the BD+ program unscramble it  Seagate  Freeagent Go(250GB/320GB) .

If a playback device manufacturer finds that its devices have been hacked, it can potentially release BD+ code that detects and circumvents the vulnerability. These programs can then be included in all new content releases.

The specifications of the BD+ virtual machine are available only to licensed device manufacturers  Seagate  Freeagent Go(500GB/640GB) .

A list of licensed commercial adopters is available from the BD+ website.

The first titles using BD+ were released in October 2007. Since November 2007, versions of BD+ protection have been circumvented by various versions of the AnyDVD HD program   Seagate  Freeagent Go(750GB/1TB) .

Other programs known to be capable of circumventing BD+ protection are DumpHD (versions 0.6 and above, along with some supporting software),  MakeMKV, and two applications from DVDFab (Passkey and HD Decrypter ).

BD-ROM Mark

BD-ROM Mark is a small amount of cryptographic data that is stored separately from normal Blu-ray Disc data  Seagate  Freeagent Goflex(250GB/320GB) .

Bit-by-bit copies that do not replicate the BD-ROM Mark have no known decoding method.  A specially licensed piece of hardware is required to insert the ROM-mark into the media during replication  Seagate Freeagent Goflex(500GB/640GB) .

Backward compatibility

Though not compulsory, the Blu-ray Disc Association recommends that Blu-ray Disc drives be capable of reading standard DVDs and CDs, for backward compatibility .A few early Blu-ray Disc players released in 2006 could play DVDs but not CDs   Seagate  Freeagent Goflex(750GB/1TB) .

Ongoing development

Although the Blu-ray Disc specification has been finalized, engineers continue to work on advancing the technology. Quad-layer (100 GB) discs have been demonstrated on a drive with modified optics  and standard unaltered optics. Hitachi stated that such a disc could be used to store 7 hours of 32 Mbit/s video (HDTV) or 3 hours and 30 minutes of 64 Mbit/s video (Cinema 4K)  Seagate  Freeagent Goflex Pro(500GB/750GB) .

In August 2006, TDK announced that they have created a working experimental Blu-ray Disc capable of holding 200 GB of data on a single side, using six 33 GB data layers.

Also, behind closed doors at CES 2007, Ritek revealed that they had successfully developed a High Definition optical disc process that extends the disc capacity to ten layers, which increases the capacity of the discs to 250 GB  Seagate  Freeagent Goflex desktop(1TB/2TB) .

However, they noted that the major obstacle is that current read/write technology does not support the additional layers.

JVC has developed a three-layer technology that allows putting both standard-definition DVD data and HD data on a BD/(standard) DVD combination   Seagate  Freeagent go for Mac(320GB/640GB) .

If successfully commercialized, this would enable the consumer to purchase a disc that can be played on current DVD players and can also reveal its HD version when played on a BD player. Japanese optical disc manufacturer Infinity announced the first "hybrid" Blu-ray Disc/(standard) DVD combo, to be released February 18, 2009   Samsung  G2 protable (250gb/320GB) .

"Code Blue" will feature four hybrid discs containing a single Blu-ray Disc layer (25 GB) and two DVD layers (9 GB) on the same side of the disc.

In January 2007, Hitachi showcased a 100 GB Blu-ray Disc, consisting of four layers containing 25 GB each.Unlike TDK and Panasonic's 100 GB discs, they claim this disc is readable on standard Blu-ray Disc drives that are currently in circulation, and it is believed that a firmware update is the only requirement to make it readable to current players and drives  Samsung  G2 protable (500GB/640GB) .

In December 2008, Pioneer Corporation unveiled a 400 GB Blu-ray Disc (containing 16 data layers, 25 GB each) that will be compatible with current players after a firmware update. Its planned launch is in the 2009–10 time frame for ROM and 2010–13 for rewritable discs. Ongoing development is under way to create a 1 TB Blu-ray Disc as soon as 2013  Samsung  S2 protable (320GB/500GB) .

At CES 2009, Panasonic unveiled the DMP-B15, the first portable Blu-ray Disc player, and Sharp introduced the LC-BD60U and LC-BD80U series, the first LCD HDTVs with integrated Blu-ray Disc players. Sharp has also announced that they will sell HDTVs with integrated Blu-ray Disc recorders in the United States by the end of 2009   Samsung S1 Mini (120GB/160GB) .

As of April 2008 , a joint licensing agreement for Blu-ray Disc has not yet been finalized. A joint licensing agreement would make it easier for companies to get a license for Blu-ray Disc without having to go to each individual company that owns a Blu-ray Disc patent. For this reason, a joint licensing agreement was eventually made for DVD by the DVD6C Licensing Agency  Samsung  S1 Mini (250GB/320GB) .

On Jan. 1, 2010, Sony, in association with Panasonic, announced plans to increase the storage capacity on their Blu-ray Discs from 25GB to 33.4 GB via a technology called i-MLSE (Maximum Likelihood Sequence Estimation). The higher-capacity discs, according to Sony, will be readable on current Blu-ray Disc players with a firmware upgrade   Samsung story station (1TB/1.5TB) .

No date has been set to include the increased space, but according to Blu-ray.com "it will likely happen sometime later this year."

On July 20, 2010, the research team of Sony and Japanese Tohoku University announced the joint development of a blue-violet laser, which will help in creating Blu-ray discs with a capacity of 1 TB (dual layer)  Samsung Story station (1.5TB/2TB) .

Blu-ray 3D

The Blu-ray Disc Association (BDA) created a task force made up of executives from the film industry and the consumer electronics and IT sectors to help define standards for putting 3D film and 3D television content on a Blu-ray Disc. On Dec. 17, 2009 the BDA officially announced 3D specs for Blu-ray Disc, allowing backward compatibility with current 2D Blu-ray players  Samsung story station Esata(1TB/1.5TB) .

The BDA has said, "The Blu-ray 3D specification calls for encoding 3D video using the "Stereo High" profile defined by Multiview Video Coding (MVC), an extension to the ITU-T H.264 Advanced Video Coding (AVC) codec currently supported by all Blu-ray Disc players  Samsung  G3 station (1TB/1.5TB) .

MPEG4-MVC compresses both left and right eye views with a typical 50% overhead compared to equivalent 2D content, and can provide full 1080p resolution backward compatibility with current 2D Blu-ray Disc players  Maxtor  one touch 4 plus (500GB/750GB) .

"  This means the MVC (3D) stream is backward compatible with H.264/AVC (2D) stream, allowing older 2D devices and software to decode stereoscopic video streams, ignoring additional information for the second view.

Sony has released a firmware upgrade for PlayStation 3 consoles that enables 3D Blu-ray Disc playback   Maxtor one touch 4 plus (1TB/1.5TB) .

However, when playing in 3D mode, the PlayStation 3 will downgrade high-def audio (such as Dolby TrueHD or DTS-HD) to standard Dolby Digital or DTS, as HDMI 1.3 does not provide enough bandwidth for both 3D video and high-def audio. They previously released support for 3D gaming on April 21, 2010  (followed by availability of 3D Movies)  Maxtor cool black(640GB/1TB) .

Variations

AVCHD

AVCHD was originally developed as a high definition format for consumer tapeless camcorders. Derived from the Blu-ray Disc specification, AVCHD uses lower data rate, simpler interactivity and cheaper media  Maxtor Black diamond (320GB/500GB) .

AVCHD specification allows recording AVC-encoded video onto DVDs, as well as onto other types of random access media like SD/SDHC memory cards, "Memory Stick" cards andhard disk drives      Hitachi  simple touch (250GB/320GB) .

Being primarily an acquisition format, AVCHD can also be used for distribution of high definition video using inexpensive media like conventional DVDs and flash memory cards. Many Blu-Ray Disc players support AVCHD playback from DVDs. Many Panasonic and JVC HD television sets and Blu-Ray Disc players support AVCHD playback from SDHC memory cards  Hitachi simple touch (320GB/500GB) .

AVCREC

AVCREC uses a BDAV container to record high definition content on conventional DVDs. Presently AVCREC is tightly integrated with the Japanese ISDB broadcast standard and is not marketed outside of Japan. AVCREC is used primarily in set-top digital video recorders and in this regard is comparable to HD REC     Hitachi  life studio (320GB/500GB) .

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