Blu-ray Disc

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Blu-ray Disc

Media type	High-density optical disc
Encoding	MPEG-2, H.264/MPEG-4 AVC, and VC-1
Capacity	25 GB (single layer) 50 GB (dual layer)
Read mechanism	405 nm laser: 1× at 36 Mbit/s 2× at 72 Mbit/s 4× at 144 Mbit/s 6× at 216 Mbit/s[1] 12× at 432 Mbit/s
Developed by	Blu-ray Disc Association
Usage	Data storage, High-definition video High-definition audio and PlayStation 3 games

Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage media format. Its main uses are high-definition video and data storage. The disc has the same dimensions as a standard DVD or CD.

The name Blu-ray Disc is derived from the blue laser (violet coloured) used to read and write this type of disc. Because of its shorter wavelength (405 nm), substantially more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A dual layer Blu-ray Disc can store 50 GB, almost six times the capacity of a double-dual layer DVD (or more than 10 times if single-layer).

During the high definition optical disc format war, Blu-ray Disc competed with the HD DVD format. On February 19, 2008, Toshiba — the main company supporting HD DVD — announced it would no longer develop, manufacture, and market HD DVD players and recorders,^[2] leading almost all other HD DVD companies to follow suit, effectively ending the format war.

Blu-ray Disc was developed by the Blu-ray Disc Association, a group representing consumer electronics, computer hardware, and motion picture production. As of August 27, 2008 more than 780 Blu-ray Disc titles have been released in the United States and more than 480 Blu-ray Disc titles have been released in Japan.^[3][4] By the end of 2008, there is expected to be a total of 1220 Blu-ray Disc titles released in the United States.^[5]

Blu-ray Disc

Media type	High-density optical disc
Encoding	MPEG-2, H.264/MPEG-4 AVC, and VC-1
Capacity	25 GB (single layer) 50 GB (dual layer)
Read mechanism	405 nm laser: 1× at 36 Mbit/s 2× at 72 Mbit/s 4× at 144 Mbit/s 6× at 216 Mbit/s[1] 12× at 432 Mbit/s
Developed by	Blu-ray Disc Association
Usage	Data storage, High-definition video High-definition audio and PlayStation 3 games

In 1998, commercial HDTV sets began to appear in the consumer market; however, there was no commonly accepted, inexpensive way to record or play HD content. In fact, there was no medium with the storage required to accommodate HD codecs, except JVC's Digital VHS and Sony's HDCAM.^[6] Nevertheless, it was well known that using lasers with shorter wavelengths would enable optical storage with higher density. When Shuji Nakamura invented practical blue laser diodes, it was a sensation, although a lengthy patent lawsuit delayed commercial introduction.^[7]

Origins

Philips and Sony started two projects applying the new diodes: UDO (Ultra Density Optical) and DVR Blue (together with Pioneer), a format of rewritable discs which would eventually become Blu-ray Disc (more specifically, BD-RE).^[8] The core technologies of the formats are essentially similar.

The first DVR Blue prototypes were unveiled at the CEATEC exhibition in October 2000.^[9] Because the Blu-ray Disc standard places the data recording layer close to the surface of the disc, early discs were susceptible to contamination and scratches and had to be enclosed in plastic cartridges for protection. In February 2002, the project was officially announced as Blu-ray,^[10] and the Blu-ray Disc Association was founded by the nine initial members.

The first consumer devices were in stores on April 10, 2003. This device was the Sony BDZ-S77; a BD-RE recorder that was made available only in Japan. The recommended price was US$3800;^[11] however, there was no standard for pre-recorded video and no movies were released for this player. The Blu-ray Disc standard was still years away as a newer, more secure DRM system was needed before Hollywood studios would accept it, not wanting to repeat the failure of the Content Scramble System used on DVDs.

Blu-ray Disc format finalized

The Blu-ray Disc physical specifications were finished in 2004.^[12] In January 2005, TDK announced that they had developed a hard coating polymer for Blu-ray Discs.^[13] The cartridges, no longer necessary, were scrapped. The BD-ROM specifications were finalized in early 2006.^[14] AACS LA, a consortium founded in 2004,^[15] had been developing the DRM platform that could be used to securely distribute movies to consumers. However, the final AACS standard was delayed,^[16] and then delayed again when an important member of the Blu-ray Disc group voiced concerns.^[17] At the request of the initial hardware manufacturers, including Toshiba, Pioneer and Samsung, an interim standard was published which did not include some features, like managed copy.^[18]

Launch and sales developments

The first BD-ROM players were shipped in the middle of June 2006, though HD DVD players beat them in the race to the market by a few months.^[19][20]

The first Blu-ray Disc titles were released on June 20, 2006. The earliest releases used MPEG-2 video compression, the same method used on DVDs. The first releases using the newer VC-1 and AVC codecs were introduced in September 2006.^[21] The first movies using dual layer discs (50 GB) were introduced in October 2006.^[22] The first audio-only release was made in March 2008.^[23]

The first mass-market Blu-ray Disc rewritable drive for the PC was the BWU-100A, released by Sony on July 18, 2006. It recorded both single and dual layer BD-R as well as BD-RE discs and had a suggested retail price of US$699.

Competition from HD DVD

The DVD Forum (which was chaired by Toshiba) was deeply split over whether to develop the more expensive blue laser technology or not. In March 2002, the forum voted to approve a proposal endorsed by Warner Bros. and other motion picture studios that involved compressing HD content onto dual-layer DVD-9 discs.^[24][25] 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. In August, Toshiba and NEC announced their competing standard Advanced Optical Disc.^[26] It was finally adopted by the DVD Forum and renamed HD DVD the next year,^[27] after being voted down twice by Blu-ray Disc Association members, prompting the U.S. Department of Justice to make preliminary investigations into the situation.^[28][29]

HD DVD had a head start in the high definition video market and Blu-ray Disc sales were slow at first. The first Blu-ray Disc player was perceived as expensive and buggy, and there were few titles available.^[30] This changed when PlayStation 3 launched, since every PS3 unit also functioned as a Blu-ray Disc player. At CES 2007 Warner proposed Total Hi Def which was a hybrid disc containing Blu-ray on one side and HD DVD on the other but it was never released. By January 2007, Blu-ray discs had outsold HD DVDs,^[31] and during the first three quarters of 2007, BD outsold HD DVDs by about two to one. Finally, by February 2008, Toshiba announced it was pulling its support for the HD DVD format, leaving Blu-ray as the victor in the video wars.^[32]

Some analysts believe that Sony's PlayStation 3 video game console played an important role in the format war, believing it acted as a catalyst for Blu-ray Disc, as the PlayStation 3 used a Blu-ray Disc drive as its primary information storage medium.^[33] They also credited Sony's more thorough and influential marketing campaign.^[34] More recently Twentieth Century Fox have cited Blu-ray Disc's adoption of the BD+ anti-copying system as the reason they supported Blu-ray Disc over HD DVD.^[35]

End of the format war

In January 2008, a day before CES 2008, Warner Brothers, the only major studio still releasing movies in both HD DVD and Blu-ray Disc format, announced it would release only in Blu-ray Disc after May 2008. This effectively included other studios which came under the Warner umbrella, such as New 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. This led to a chain reaction in the industry, including major U.S. retailers such as Best Buy, Wal-Mart, and Circuit City dropping HD DVD in their stores. A major European retailer, Woolworths, dropped HD DVD from its inventory. 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 be ending production of HD DVD devices,^[36] allowing Blu-ray Disc to become the industry standard for high-density optical disks. Universal Studios, the sole major movie studio to back HD DVD since inception, shortly after Toshiba's announcement, said "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."^[37] 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.^[38]

Former HD DVD supporter Microsoft had stated that they were not pursuing a Blu-ray Disc drive for the Xbox 360, and would instead focus on their digital downloads from the Xbox Live Marketplace.^[39]

Blu-ray Disc began making serious strides as soon as the format war ended. 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, with most experts predicting the business will take off in a significant fashion in the fourth quarter of 2008, when BD Live software and players--which offer a variety of Web-enabled features, from downloadable trailers to chat and instant-messaging functions--start hitting the market.

According to Singulus Technologies AG, Blu-ray is being adopted faster than the DVD format was at the same period of its development. This conclusion was made due to 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.^[40]

Technical specifications

Physical size	Single layer capacity	Dual layer capacity	Note
12 cm, single sided	25 GB (23.28 GiB)	50 GB (46.56 GiB)	Standard disc size
8 cm, single sided	7.8 GB (7.26 GiB)	15.6 GB (14.53 GiB)	Mini disc size

Laser and optics

Blu-ray Disc uses a "blue" (technically violet) laser operating at a wavelength of 405 nm to read and write data. Conventional DVDs and CDs use red and near infrared lasers at 650 nm and 780 nm respectively.

The blue-violet laser's shorter wavelength makes it possible to store more information on a 12 cm CD/DVD sized disc. 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 and making the cover layer thinner to avoid unwanted optical effects, the laser beam can be focused to a smaller spot. This allows more information to be stored in the same area. For Blu-ray Disc, the spot size is 580 nm.^[41] In addition to the optical improvements, Blu-ray Discs feature improvements in data encoding that further increase the capacity. (See Compact disc for information on optical discs' physical structure.)

Hard-coating technology

Because 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.

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's rewritable media are spin-coated with a scratch-resistant and antistatic coating. Verbatim's recordable and rewritable Blu-ray Disc discs use their own proprietary hard-coat technology called ScratchGuard.

Recording speed

Drive speed	Data rate		Write time for Blu-ray Disc (minutes)
	Mbit/s	MB/s	Single Layer	Dual Layer
1×	36	4.5	90	180
2×	72	9	45	90
4×	144	18	23	45
6×	216	27	15	30
8×*	288	36	12	23
12×**	432	54	8	15

* On August 8, 2008, Japanese Buffalo announced that it will ship the first 8x Blu-ray burners in Japan starting from September 2008.

** Theoretical

Software standards

Codecs

Codecs are compression schemes that store audio and video more efficiently, either giving longer play time or higher quality per megabyte. There are both lossy and lossless compression techniques.

The BD-ROM specification mandates certain codec compatibilities for both hardware decoders (players) and the movie-software (content). For video, all players are required to support MPEG-2, H.264/AVC, and SMPTE VC-1. MPEG-2 is the codec used on regular DVDs, which allows backwards compatibility. H.264/AVC was developed by MPEG and VCEG as a modern successor of H.263 . VC-1 is another MPEG-4 derivative codec mostly developed by Microsoft. 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 runtime, due to differences in compression efficiency. 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 H.264) typically achieve a video runtime twice that of MPEG-2, with comparable quality.

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 that were launched throughout 2006. Modern releases are now often encoded in either H.264/AVC or VC-1, allowing film studios to place all content on one disc, reducing costs and improving ease of use. Using these codecs will also free many GB 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; for example the Blu-ray release of Superman Returns uses VC-1 for the feature film and MPEG-2 for bonus content (presumably because it is simply ported from the DVD release).

For audio, BD-ROM players are required to support Dolby Digital, DTS, and linear PCM. Players may optionally support Dolby Digital Plus and DTS-HD High Resolution Audio, as well as lossless formats Dolby TrueHD and DTS-HD Master Audio. 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.^[42]

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). Blu-ray 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 bitrate 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.^[43]

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. Java is used to implement interactive menus on Blu-ray Discs, as opposed to the method used on DVD video discs, which uses pre-rendered MPEG segments and selectable subtitle pictures, which is considerably more primitive and less seamless. Java creator James Gosling, at the conference, 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 that are not included on the disc at pressing time. This Java Version is called BD-J and is a subset of the Globally Executable MHP (GEM) standard. GEM is the world-wide version of the Multimedia Home Platform standard.

Region codes

Regions for Blu-ray standard^[44]

A: East Asia (except Mainland China and Mongolia), Southeast Asia, North America, South America and their dependencies. B: Africa, Southwest Asia, Europe (except Russia and Kazakhstan), Oceania and their dependencies. C: Central Asia, East Asia (Mainland China and Mongolia only), South Asia, Europe (Russia and Kazakhstan only) and their dependencies.

Blu-ray Discs may be encoded with a region code, intended to restrict the area of the world in which they can be played, similar in principle to the DVD region codes, although the used geographical regions differ. Blu-ray Disc players sold in a certain region may only play discs encoded for that region. The purpose of this system is to allow motion picture studios to control the various aspects of a release (including content, date, and in particular price) according to the region. Discs may also be produced without region coding, so they can be played on all devices. The countries of the major Blu-ray manufacturers (Japan, Korea, Malaysia) are in the same region as North America. As of early 2008, about two-thirds of all released discs were region-free.^[45]

Major studios have different region coding policies. Paramount Pictures and Universal Studios have released all of their titles region free.^[46][47] Sony Pictures and Warner Bros have released most of their titles region free, but titles released by Warner's New Line division are region-coded.^[48][49] Lionsgate and Walt Disney Pictures have released a mix of titles that were region free and region coded.^[50][51] 20th Century Fox has released all but one of their titles region coded.^[52]

However, since the demise of the HD-DVD format which did not support Region Coding, the majority of Blu-ray releases are now region coded.

In the Blu-ray region coding system, the United States is placed in region A while regions B and C are used for countries which can experience localization delays before U.S. titles are officially released. The opposite, though, is sometimes true and a few new titles such as Harry Potter and the Goblet of Fire and Running Scared were released in certain European countries before the U.S. release.^[53] In response to the DVD region system, multi-region and region-free DVD players became dominant in certai

Digital rights management (DRM)

The Blu-ray Disc format employs several layers of digital rights management.^[55][56]

AACS decryption process

Advanced Access Content System (AACS) is a standard for content distribution and digital rights management. It is developed by AS Licensing Administrator, LLC (AACS LA), a consortium that includes Disney, Intel, Microsoft, Matsushita (Panasonic), Warner Bros., IBM, Toshiba and Sony.

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). New releases will use new, uncompromised keys.^[57] However, now (August 2008) all decryption keys are available on the Internet.^{[citation needed]}

BD+ was developed by Cryptography Research Inc. and is based on their concept of Self-Protecting Digital Content.^[58] BD+ is effectively a small virtual machine embedded in authorized players. It allows content providers to include executable programs on Blu-ray Discs. Such programs can:^[55]

• 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.
• 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.

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.

If a publisher desires BD+ has the ability to limit playback of a Blu-Ray Disc to the first Blu-Ray playback device in which the disc is played.^{[citation needed]}

The specifications of the BD+ virtual machine are available only to licensed device manufacturers. A list of licensed adopters is available from the BD+ website.

BD+ was made available for content publishers in June 2007.^[59] The first titles using BD+ were released in October the same year. Players from Samsung and LG had problems playing back those titles until the manufacturers updated their firmware, but this problem was later identified as being related to BD-Java use, not BD+.^[60] BD+ protection was fully circumvented with the release 6.4.0.0 of AnyDVD HD program.

BD-ROM Mark is a small amount of cryptographic data that is stored separately from normal Blu-ray Disc data. Bit-by-bit copies that do not replicate the BD-ROM Mark are impossible to decode. A specially licensed piece of hardware is required to insert the ROM-mark into the media during replication. Through licensing of the special hardware element, the BDA believes that it can eliminate the possibility of mass producing BD-ROMs without authorization.

Player profiles

The BD-ROM specification defines four Blu-ray Disc player profiles which includes an audio only player profile (BD-Audio) that does not require video decoding or BD-J.^[61] All three of the video based player profiles (BD-Video) are required to have a full implementation of BD-J, but with varying levels of hardware support.

Feature	BD-Audio	BD-Video
		Grace Period [d]	Bonus View [e]	BD-Live
	Profile 3.0 [c]	Profile 1.0	Profile 1.1	Profile 2.0
Built-in persistent memory	No	64 KB	64 KB	64 KB
Local storage capability[a]	No	Optional	256 MB	1 GB
Secondary video decoder (PiP)	No	Optional	Mandatory	Mandatory
Secondary audio decoder[b]	No	Optional	Mandatory	Mandatory
Virtual file system	No	Optional	Mandatory	Mandatory
Internet connection capability	No	No	No	Mandatory

^ a This is used for storing audio/video and title updates. It can either be built in memory or removable media, such as a memory card or USB flash memory.
^ b A secondary audio decoder is typically used for interactive audio and commentary.
^ c Profile 3.0 is a separate audio only player profile. As of 2008-06-26, only one known Blu-ray record has been released and it has been confirmed to work on the PS3.^[62][63]
^ d Is also known as Initial Standard profile.
^ e Is also known as Final Standard profile.

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.^[64] When Blu-ray software authored with interactive features dependent on Bonus View or BD-Live hardware capabilities are played on Profile 1.0 players they will be able to play the main feature of the disc but some extra features may not be available or may offer limited capability.^[65]

Except the LG-BH100, the LG-BH200, the PlayStation 3, and the Samsung BD-UP5000, Profile 1.0 players can not be upgraded to be Bonus View or BD-Live compliant.^[66][67][68]

Backward compatibility

Though not compulsory, the Blu-ray Disc Association recommends that Blu-ray Disc drives should be capable of reading standard DVDs and CDs for backward compatibility.^[69] A few early Blu-ray Disc players released in 2006 could play DVDs but not CDs (the LG BH100, Pioneer BDP-HD1, and Sony BDP-S1)^[70][71][72] but all current Blu-ray Disc players are capable of both DVD and CD playback.^[73]

Ongoing development

Front of an experimental 200GB rewritable Blu-ray Disc

Although the Blu-ray Disc specification has been finalized, engineers continue working to advance the technology. Quad-layer (100 GB) discs have been demonstrated on a drive with modified optics (TDK version) and standard unaltered optics ("Hitachi used a standard drive.").^[74][75] Hitachi stated that such a disc could be used to store 7 hours of 32 Mbit/s video (HDTV) or 3.5 hours of 64 Mbit/s video (Cinema 4K). Furthermore TDK announced in August 2006 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.^[76]

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 10 layers. That increases the capacity of the discs to 250 GB. However, they noted that the major obstacle is that current reader and writer technology does not support the additional layers.^[77]

JVC has developed a three-layer technology that allows putting both standard-definition DVD data and HD data on a BD/DVD combo. If successfully commercialized, this would enable the consumer to purchase a disc which could be played on current DVD players, and reveal its HD version when played on a new BD player.^[78] This hybrid disc does not appear to be ready for production and no titles have been announced that would use this disc structure.

In January 2007, Hitachi showcased a 100 GB Blu-ray Disc, which consists of four layers containing 25 GB each.^[79] 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.^[80]

As of April, 2008 a joint licensing agreement for Blu-ray Disc has not yet been finalized.^[81] 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.^[82]

Variants

Mini Blu-ray Disc

The Mini Blu-ray Disc (also, Mini-BD and Mini Blu-ray) is a compact 8cm (~3in) diameter variant of the Blu-ray Disc that can store approximately 7.5 GB of data. It is similar in concept to the MiniDVD.

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.^[83]

BD9/BD5 Blu-ray Disc

See also: 3× DVD

BD9 and BD5 are lower capacity variants of the Blu-ray Disc that contain Blu-ray compatible video and audio streams contained on a conventional DVD (650 nm wavelength / red laser) optical disc. Such discs offer the use of the same advanced compression technologies available to Blu-ray discs (including MPEG-4-AVC/H.264, SMPTE-421M/VC-1 and MPEG-2) while using lower cost legacy media. BD9 uses a standard 8152MB DVD9 dual-layer disc while BD5 uses a standard 4489MB DVD5 single-layer disc.^[84]

Given that Blu-ray Discs are assumed to have a minimum transfer rate of 30.25 Mbit/s, BD9/BD5 discs must be spun at high speed, equivalent to a 3× DVD drive speed or greater.

BD9 and BD5 discs can be authored using home computers for private showing using standard DVD±R recorders. AACS digital rights management is optional.^[85]

The BD9 format was originally proposed by Warner Home Video, as a cost-effective alternative to regular Blu-ray Discs.^[86] It was adopted as part of the BD-ROM basic format, file system and AV specifications. BD5 and BD9 are similar to 3× DVD.

Blu-ray Disc

AVCREC

See also: HD REC

AVCREC is an official^[87] lower capacity variant of the Blu-ray Disc used for storing Blu-ray Disc compatible content on conventional DVD discs. It is being promoted for use in camcorders, distribution of short HD broadcast content and other cost-sensitive distribution needs. It is similar to HD REC for HD DVD.

Note that AVCREC is not the same as AVCHD content stored on DVD. The latter is a media independent format and is used presently in tapeless camcorders that record onto DVD and Blu-ray disks, as well as onto SecureDigital and MemoryStick memory cards. Playing back AVCHD content on a Blu-ray player may require modification of AVCHD directory structure, but does not require re-encoding of video files themselves.^[88]

[edit] Blu-ray Disc recordable

Main article: Blu-ray Disc recordable

Blu-ray Disc recordable refers to two optical disc formats that can be recorded with an optical disc recorder. BD-R discs can be written to once, whereas BD-RE can be erased and re-recorded multiple times. The theoretical maximum speed for Blu-ray Discs is about 12× as the speed of rotation (10,000 rpm) causes too much wobble for the discs to be read properly, similar to the 20× and 52× respective maximum speeds of DVDs and CDs.

Since September 2007, BD-RE was also available in the smaller 8 cm Mini Blu-ray Disc diameter size.^[83][89]

On September 18, 2007, Pioneer and Mitsubishi co-developed 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.^[90]

In February 2008, Taiyo Yuden, Mitsubishi and Maxell released the first BD-R LTH Discs,^[91] and in March 2008, Sony's PlayStation 3 gained official support for BD-R LTH Discs with the 2.20 firmware update.^[92]

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

DIFFERENCE BETWEEN 32 AND 64 BIT PROCESSORS

In the future, the battle between 64 bit vs 32 bit processors will inevitably yield the 64 bit processor as the victor, but this transition is going to take some time.

First, I’ll talk about the pure mathematics and structure of the processors that are involved here. I’ll keep this part short and sweet.

A bit is short for “binary digit.” It is basically how a computer stores and makes references to data, memory, etc. A bit can have a value of 1 or 0, that’s it. So binary code is streams of 1’s and 0’s, such as this random sequence 100100100111. These bits are also how your processor does calculations. By using 32 bits your processor can represent numbers from 0 to 4,294,967,295 while a 64-bit machine can represent numbers from 0 to 18,446,744,073,709,551,615. Obviously this means your computer can do math with larger numbers, and be more efficient with smaller numbers.

Now see, that description wasn’t too bad, but the question is how does this affect you, the average PC owner? The largest benefit will go to academic institutions and private companies, where large calculations are being performed, huge databases are being accessed, and complex problems are being solved.

Everyone that doesn’t fall into that category will see some benefit of using 64 bit processors over 32 bit processors, but not much in today’s marketplace. The AMD Athlon 64-bit processor is completely backward compatible, meaning you can currently use it with 32-bit operating systems and software programs. You will see some benefits by using this setup, but because the programs weren’t written to take advantage of the extra power, they won’t use much of it.

The true benefits of this set up don’t come from the amount of bits, but by the improved structure of the 64 bit vs 32 bit processor's older structure. A 64-bit processor is made with more advanced silicon processes, have more transistors, and faster speeds. This is currently where the true benefit of switching to a 64-bit processor lays.

As for 64-bit operating systems and software, many are in the works, but nothing is in final version. Microsoft has released a beta version of Windows XP that takes advantage of the 64 bit technology, but there are still issues. The problem is when you run 32-bit software programs in the environment of a 64-bit operating system. Many programs won’t work properly, such as Adobe Acrobat and Windows Media Player, for example. Another issue is RAM. You really need about 4 GB of RAM to take full advantage of the capabilities offered by a 64-bit processor, while most PC owners have less than 1 GB under their computer’s hood.

So, the question now is should you buy a 64 bit processor now, or wait?

Disadvantages:

You’re currently not able to take full advantage of the technology because the software vendors haven’t made the switch from 32-bit to 64-bit processors.

Most AMD Athlon 64 bit processors are expensive, with prices sure to go down in the future.

Advantages:

Better performance out of a 32-bit operating system.

Probably the last processor you’ll have to buy for many years to come.

You’ll be the talk of all your friends!
As you can see, a sound argument can be made for both cases. You’ll have to determine if the differences will benefit your situation and computing future. I’ll leave the ultimate decision up to you.

Advanced Micro Devices, Inc. (AMD) (NYSE: AMD) is an American multinational semiconductor company based in Sunnyvale, California, that develops computer processors and related technologies for commercial and consumer markets. Its main products include microprocessors, motherboard chipsets, embedded processors and graphics processors for servers, workstations and personal computers, and processor technologies for handheld devices, digital television, and game consoles.
AMD is the second-largest global supplier of microprocessors based on the x86 architecture after Intel Corporation, and the third-largest supplier of graphics processing units. It also owns 21 percent of Spansion, a supplier of non-volatile flash memory. In 2007, AMD ranked eleventh among semiconductor manufacturers in terms of revenue.[1]
Corporate history
Advanced Micro Devices was founded on May 1, 1969, by a group of former executives from Fairchild Semiconductor, including Jerry Sanders, III, Ed Turney, John Carey, Sven Simonsen, Jack Gifford and three members from Gifford's team, Frank Botte, Jim Giles, and Larry Stenger. The company began as a producer of logic chips, then entered the RAM chip business in 1975. That same year, it introduced a reverse-engineered clone of the Intel 8080 microprocessor. During this period, AMD also designed and produced a series of bit-slice processor elements (Am2900, Am29116, Am293xx) which were used in various minicomputer designs.
During this time, AMD attempted to embrace the perceived shift towards RISC with their own AMD 29K processor, and they attempted to diversify into graphics and audio devices as well as EPROM memory. It had some success in the mid-80s with the AMD7910 and AMD7911 "World Chip" FSK modem, one of the first multistandard devices that covered both Bell and CCITT tones at up to 1200 baud half duplex or 300/300 full duplex. While the AMD 29K survived as an embedded processor and AMD spinoff Spansion continues to make industry leading flash memory, AMD was not as successful with its other endeavors. AMD decided to switch gears and concentrate solely on Intel-compatible microprocessors and flash memory. This put them in direct competition with Intel for x86 compatible processors and their flash memory secondary markets.
It has been reported in December 2006 that AMD along with its main rival in the graphics industry nVidia, received subpoenas from the Justice Department regarding possible antitrust violations in the graphics card industry, including the act of fixing prices.[2]
AMD announced a merger with ATI Technologies on July 24, 2006. AMD paid $4.3 billion in cash and 58 million shares of its stock for a total of US$5.4 billion. The merger completed on October 25, 2006[3] and ATI is now part of AMD.

Microsoft Windows is a series of software operating systems produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces (GUIs). Microsoft Windows came to dominate the world's personal computer market, overtaking Mac OS, which had been introduced previously. At the 2004 IDC Directions conference, it was stated that Windows had approximately 90% of the client operating system market. The most recent client version of Windows is Windows Vista; the current server version is Windows Server 2008.

Microsoft has taken two parallel routes in its operating systems. One route has been for the home user and the other has been for the professional IT user. The dual routes have generally led to home versions having greater multimedia support and less functionality in networking and security, and professional versions having inferior multimedia support and better networking and security.[citation needed]
The first version of Microsoft Windows, version 1.0, released in November 1985, lacked a degree of functionality and achieved little popularity, and was to compete with Apple's own operating system.[citation needed] Windows 1.0 is not a complete operating system; rather, it extends MS-DOS. Microsoft Windows version 2.0 was released in November, 1987 and was slightly more popular than its predecessor. Windows 2.03 (release date January 1988) had changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights.
Microsoft Windows version 3.0, released in 1990, was the first Microsoft Windows version to achieve broad commercial success, selling 2 million copies in the first six months. It featured improvements to the user interface and to multitasking capabilities. It received a facelift in Windows 3.1, made generally available on March 1, 1992. Windows 3.1 support ended on December 31, 2001.
In July 1993, Microsoft released Windows NT based on a new kernel. NT was considered to be the professional OS and was the first Windows version to utilize preemptive multitasking.[citation needed]. Windows NT would later be retooled to also function as a home operating system, with Windows XP.
On August 24th 1995, Microsoft released Windows 95, a new, and major, consumer version that made further changes to the user interface, and also used preemptive multitasking. Windows 95 was designed to replace not only Windows 3.1, but also Windows for Workgroups, and MS-DOS. It was also the first Windows operating system to use Plug and Play capabilities. The changes Windows 95 brought to the desktop were revolutionary, as opposed to evolutionary, such as those in Windows 98 and Windows Me. Mainstream support for Windows 95 ended on December 31, 2000 and extended support for Windows 95 ended on December 31, 2001.
The next in the consumer line was Microsoft Windows 98 released on June 25th, 1998. It was substantially criticized for its slowness and for its unreliability compared with Windows 95, but many of its basic problems were later rectified with the release of Windows 98 Second Edition in 1999.[citation needed] Mainstream support for Windows 98 ended on June 30, 2002 and extended support for Windows 98 ended on July 11, 2006.
As part of its "professional" line, Microsoft released Windows 2000 in February 2000. The consumer version following Windows 98 was Windows Me (Windows Millennium Edition). Released in September 2000, Windows Me implemented a number of new technologies for Microsoft: most notably publicized was "Universal Plug and Play."
In October 2001, Microsoft released Windows XP, a version built on the Windows NT kernel that also retained the consumer-oriented usability of Windows 95 and its successors. This new version was widely praised in computer magazines. It shipped in two distinct editions, "Home" and "Professional", the former lacking many of the superior security and networking features of the Professional edition. Additionally, the first "Media Center" edition was released in 2002, with an emphasis on support for DVD and TV functionality including program recording and a remote control. Mainstream support for Windows XP will continue until April 14, 2009 and extended support will continue until April 8, 2014.
In April 2003, Windows Server 2003 was introduced, replacing the Windows 2000 line of server products with a number of new features and a strong focus on security; this was followed in December 2005 by Windows Server 2003 R2.
On January 30, 2007 Microsoft released Windows Vista. It contains a number of new features, from a redesigned shell and user interface to significant technical changes, with a particular focus on security features. It is available in a number of different editions, and has been subject to some criticism.

Antivirus software are computer programs that attempt to identify, neutralize or eliminate malicious software. The term "antivirus" is used because the earliest examples were designed exclusively to combat computer viruses; however most modern antivirus software is now designed to combat a wide range of threats, including worms, phishing attacks, rootkits, trojan horses and other malware. Antivirus software typically uses two different approaches to accomplish this:
· examining (scanning) files to look for known viruses matching definitions in a virus dictionary, and
· identifying suspicious behavior from any computer program which might indicate infection.
The second approach is called heuristic analysis. Such analysis may include data captures, port monitoring and other methods.
Most commercial antivirus software uses both of these approaches, with an emphasis on the virus dictionary approach. Although some people consider network firewalls to be a type of antivirus software, this categorization is not correct.

In information technology, Universal Serial Bus (USB) is a serial bus standard to interface devices to a host computer. USB was designed to allow many peripherals to be connected using a single standardized interface socket and to improve the plug-and-play capabilities by allowing hot swapping, that is, by allowing devices to be connected and disconnected without rebooting the computer or turning off the device. Other convenient features include providing power to low-consumption devices without the need for an external power supply and allowing many devices to be used without requiring manufacturer specific, individual device drivers to be installed.
USB is intended to help retire all legacy varieties of serial and parallel ports. USB can connect computer peripherals such as mice, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, and flash drives. For many of those devices USB has become the standard connection method. USB was originally designed for personal computers, but it has become commonplace on other devices such as PDAs and video game consoles, and as a bridging power cord between a device and an AC adapter plugged into a wall plug for charging purposes. As of 2008, there are about 2 billion USB devices in the world.[1]
The design of USB is standardized by the USB Implementers Forum (USB-IF), an industry standards body incorporating leading companies from the computer and electronics industries. Notable members have included Agere (now merged with LSI Corporation), Apple Inc., Hewlett-Packard, Intel, NEC, and Microsoft.

A network switch
A network switch is a broad and imprecise marketing term for a computer networking device that connects network segments.
The term commonly refers to a Network bridge that processes and routes data at the Data link layer (layer 2) of the OSI model. Switches that additionally process data at the Network layer (layer 3) (and above) are often referred to as Layer 3 switches or Multilayer switches.
The term Network switch does not generally encompass unintelligent or passive network devices such as hubs and repeaters.
The first Ethernet switch was introduced by Kalpana in 1989. [1]
As with hubs, Ethernet implementations of network switches support either 10/100 Mbit/s or 10/100/1000 Mbit/s ports Ethernet standards. Large switches may have 10 Gbit/s ports. Switches differ from hubs in that they can have ports of different speed.
The network switch, packet switch (or just switch) plays an integral part in most Ethernet local area networks or LANs. Mid-to-large sized LANs contain a number of linked managed switches. Small office, home office (SOHO) applications typically use a single switch, or an all-purpose converged device such as gateway access to small office/home office broadband services such as DSL router or cable, WiFi router. In most of these cases, the end user device contains a router and components that interface to the particular physical broadband technology, as in the Linksys 8-port and 48-port devices. User devices may also include a telephone interface to VoIP.
In simple terms, in the context of a standard 10/100 Ethernet switch, a switch operates at the data-link layer of the OSI model to create a different collision domain per switch port. This basically says that if you have 4 computers A/B/C/D on 4 switch ports, then A and B can transfer data between them as well as C and D at the same time, and they will never interfere with each others conversations. That is the basic idea in a nutshell. In the case of a "hub" then they would all have to share the bandwidth, run in half-duplex and there would be collisions and retransmissions. Using a switch is called micro-segmentation and it allows you to have dedicated bandwidth on point to point connections with every computer and can therefore run in full duplex with no collisions.

Computer software, or just software is a general term used to describe a collection of computer programs, procedures and documentation that perform some tasks on a computer system. The term includes application software such as word processors which perform productive tasks for users, system software such as operating systems, which interface with hardware to provide the necessary services for application software, and middleware which controls and co-ordinates distributed systems.

"Software" is sometimes used in a broader context to mean anything which is not hardware but which is used with hardware, such as film, tapes and records.
Types

Practical computer systems divide software systems into three major classes: system software, programming software and application software, although the distinction is arbitrary, and often blurred.

* System software helps run the computer hardware and computer system. It includes operating systems, device drivers, diagnostic tools, servers, windowing systems, utilities and more. The purpose of systems software is to insulate the applications programmer as much as possible from the details of the particular computer complex being used, especially memory and other hardware features, and such as accessory devices as communications, printers, readers, displays, keyboards, etc.
* Programming software usually provides tools to assist a programmer in writing computer programs, and software using different programming languages in a more convenient way. The tools include text editors, compilers, interpreters, linkers, debuggers, and so on. An Integrated development environment (IDE) merges those tools into a software bundle, and a programmer may not need to type multiple commands for compiling, interpreting, debugging, tracing, and etc., because the IDE usually has an advanced graphical user interface, or GUI.
* Application software allows end users to accomplish one or more specific (non-computer related) tasks. Typical applications include industrial automation, business software, educational software, medical software, databases, and computer games. Businesses are probably the biggest users of application software, but almost every field of human activity now uses some form of application software.

More commonly referred to as an MP3 player, a digital audio player is a consumer electronics device that stores, organizes and plays audio files. Some DAPs are also referred to as portable media players as they have image-viewing and/or video-playing support.
The predecessors to digital audio players are portable CD and MiniDisc players, which are commonly known as "Portable Audio Devices". Although the data is digitally stored on discs, neither one is able to support digital file formats.
The first mass-produced DAP was created in 1997 by SaeHan Information Systems, which domestically sold its “MPMan” player in the middle of 1998.[1] The South Korean company then licensed the players to Eiger Labs which distributed them—now branded as Eiger Labs MPMan F10—to the North American market during the summer of 1998.[2] The flash-based players were available in 16 MB storage capacity.
The Rio PMP300 from Diamond Multimedia was introduced in September 1998, a few months after the MPMan. It was a success during the holiday season, with sales exceeding expectations.[3] Interest and investment in digital music were subsequently spurred from it.[4] Because of the player's notoriety as the target of a major lawsuit, the Rio is erroneously assumed to be the first DAP.[5]
In 1998, Compaq developed the first hard drive based DAP using a 2.5" laptop drive. It was licensed to HanGo Electronics (now known as Remote Solution), which first sold the PJB-100 (Personal Jukebox) in 1999. The player had an initial capacity of 4.8 GB, which was advertised to be able to hold 1200 songs.[6]
In October 2001, Apple Computer (now known as Apple Inc.) unveiled the first generation iPod, the 5 GB hard drive based DAP with a 1.8" Toshiba drive. With the development of a minimalistic user interface and a smaller form factor, the iPod was initially notable within users of the Macintosh community. In July 2002, Apple introduced the second generation update to the iPod. It was compatible with Windows computers through Musicmatch Jukebox (now known as Y!Music Musicmatch Jukebox). The iPod series, which grew to include microdrive and flash-based players, has become the market leader in DAPs.
In 2002, Archos released the first official PMP, the Archos Jukebox Multimedia.[7] Manufacturers have since implemented abilities to view images and play videos into their devices.
Although online music services such as RealNetworks’ Rhapsody also offer legal downloads through a subscription plan, the launch of the iTunes Store in 2003 established the model of selling individual songs and albums for purchase.