dvd

DVD, also known as Digital Video Disc or Digital Versatile Disc, is an optical disc storage media format, and was invented and developed by Philips,Sony, Toshiba, and Time Warner in 1995. Its main uses are video and data storage. DVDs are of the same dimensions as compact discs (CDs), but are capable of storing almost seven times as much data (Dell XPS M1210 Battery) .

Variations of the term DVD often indicate the way data is stored on the discs: DVD-ROM (read only memory) has data that can only be read and not written; DVD-R and DVD+R (recordable) can record data only once, and then function as a DVD-ROM; DVD-RW (re-writable), DVD+RW, and DVD-RAM(random access memory) can all record and erase data multiple times. The wavelength used by standard DVD lasers is 650 nm;^[4] thus, the light has ared color (Dell Studio XPS 1340 Battery) .

DVD-Video and DVD-Audio discs refer to properly formatted and structured video and audio content, respectively. Other types of DVDs, including those with video content, may be referred to as DVD Data discs.

History

In 1993, two optical disc storage formats were being developed. One was the MultiMedia Compact Disc (MMCD) also called CDi, backed by Philips andSony, and the other was the Super Density (SD) disc, supported by Toshiba, Time Warner, Matsushita Electric, Hitachi, Mitsubishi Electric, Pioneer,Thomson, and JVC (Dell Studio XPS 1640 Battery) .

Representatives of the SD camp approached IBM, asking for advice on the file system to use for their disc as well as seeking support for their format for storing computer data. Alan E. Bell, a researcher from IBM's Almaden Research Center received that request and also learned of the MMCD development project. Wary of being caught in a repeat of the costly videotape format war between VHS and Betamax in the 1980s, he convened a group of computer industry experts, including representatives from Apple, Microsoft, Sun, Dell, and many others (Dell Vostro 1710 Battery) .

This group was referred to as the Technical Working Group, or TWG.

The TWG voted to boycott both formats unless the two camps agreed on a single, converged standard. Lou Gerstner, president of IBM, was recruited to apply pressure on the executives of the warring factions. Eventually, the computer companies won the day, and a single format, now called DVD, was agreed upon (ASUS EEE PC900 battery) .

The TWG also collaborated with the Optical Storage Technology Association (OSTA) on the use of their implementation of the ISO-13346 file system (known as Universal Disc Format [UDF]) for use on the new DVDs.

Philips and Sony decided it was in their best interest to avoid another format war over their MultiMedia Compact Disc, and agreed to unify with companies backing the Super Density Disc to release a single format with technologies from both (Dell RM791 battery) .

The specification was mostly similar to Toshiba and Matsushita's Super Density Disc, except for the dual-layer option (MMCD was single-sided and optionally dual-layer, whereas SD was single-layer but optionally double-sided) and EFMPlus modulation.

EFMPlus was chosen because of its great resilience to disc damage, such as scratches and fingerprints. EFMPlus, created by Kees Immink (who also designed EFM), is 6% less efficient than the modulation technique originally used by Toshiba, which resulted in a capacity of 4.7 GB, as opposed to the original 5 GB (Sony VGP-BPS13 battery) .

The result was the DVD specification, finalized for the DVD movie player and DVD-ROM computer applications in December 1995.

The DVD Video format was first introduced by Toshiba in Japan in November 1996, in the United States in March 1997 (test marketed), in Europe in October 1998, and in Australia in February 1999.

In May 1997, the DVD Consortium was replaced by the DVD Forum, which is open to all other companies (Sony VGP-BPL9 battery) .

DVD specifications created and updated by the DVD Forum are published as so-called DVD Books (e.g. DVD-ROM Book, DVD-Audio Book, DVD-Video Book, DVD-R Book, DVD-RW Book, DVD-RAM Book, DVD-AR Book, DVD-VR Book, etc.).

Some specifications for mechanical, physical and optical characteristics of DVD optical discs can be downloaded as freely available standards from theISO website (Sony VGP-BPL11 battery) .

Also, the DVD+RW Alliance publishes competing DVD specifications such as DVD+R, DVD+R DL, DVD+RW or DVD+RW DL. These DVD formats are also ISO standards.

Some of DVD specifications (e.g. for DVD-Video) are not publicly available and can be obtained only from the DVD Format/Logo Licensing Corporation for a fee of US $5000. Every subscriber must sign a non-disclosure agreement as certain information in the DVD Book is proprietary and confidential (Sony VGP-BPL15 battery) .

Etymology

The official DVD specification documents have never defined the initialism DVD. Usage in the present day varies, with Digital Versatile Disc, Digital Video Disc, and DVD being the most common.

DVD was originally used as an initialism for the unofficial term digital videodisk. Later, as reported at the time of the specification finalization in 1995, the letters officially stood for Digital Versatile Disc (due to nonvideo applications) (Dell Inspiron E1505 battery) .

A newsgroup FAQ written by Jim Taylor (a prominent figure in the industry) claims that four years later, in 1999, the DVD Forum stated that the format name was simply the three letters "DVD" and did not stand for anything.

The DVD Forum website has a section called "DVD Primer" in which the answer to the question, "What does DVD mean?" reads, "The keyword is 'versatile.' Digital Versatile Discs provide superb video, audio and data storage and access—all on one disc (Dell Latitude E6400 battery) ."

Identification (MID)

The DVD is made of a spiral groove read or written starting at the center. The form of the groove encodes unalterable identification data known as Media Identification Code (MID). The MID contains data such as the manufacturer and model, byte capacity, allowed data rates (also known as speed), etc (HP Pavilion dv6000 Battery) .

Capacity

Capacity and nomenclature[19][20] SS = single-sided, DS = double-sided, SL = single-layer, DL = dual-layer
Designation		Sides	Layers (total)	Diameter	Capacity
				(cm)	(GB)	(GiB)
DVD-1[21]	SS SL	1	1	8	1.46	1.36
DVD-2	SS DL	1	2	8	2.66	2.47
DVD-3	DS SL	2	2	8	2.92	2.72
DVD-4	DS DL	2	4	8	5.32	4.95
DVD-5	SS SL	1	1	12	4.70	4.37
DVD-9	SS DL	1	2	12	8.54	7.95
DVD-10	DS SL	2	2	12	9.40	8.75
DVD-14[22]	DS SL+DL	2	3	12	13.24	12.33
DVD-18	DS DL	2	4	12	17.08	15.90

Capacity and nomenclature of (re)writable discs
Designation		Sides	Layers (total)	Diameter	Capacity
				(cm)	(GB)	(GiB)
DVD-R	SS SL (1.0)	1	1	12	3.95	3.68
DVD-R	SS SL (2.0)	1	1	12	4.70	4.37
DVD-RW	SS SL	1	1	12	4.70	4.37
DVD+R	SS SL	1	1	12	4.70	4.37
DVD+RW	SS SL	1	1	12	4.70	4.37
DVD-R	DS SL	2	2	12	9.40	8.75
DVD-RW	DS SL	2	2	12	9.40	8.75
DVD+R	DS SL	2	2	12	9.40	8.75
DVD+RW	DS SL	2	2	12	9.40	8.75
DVD-RAM	SS SL	1	1	8	1.46	1.36*
DVD-RAM	DS SL	2	2	8	2.65	2.47*
DVD-RAM	SS SL (1.0)	1	1	12	2.58	2.40
DVD-RAM	SS SL (2.0)	1	1	12	4.70	4.37
DVD-RAM	DS SL (1.0)	2	2	12	5.16	4.80
DVD-RAM	DS SL (2.0)	2	2	12	9.40	8.75*

The basic types of DVD (12 cm diameter, single-sided or homogeneous double-sided) are referred to by a rough approximation of their capacity in gigabytes. In draft versions of the specification, DVD-5 indeed held five gigabytes, but some parameters were changed later on as explained above, so the capacity decreased. Other formats, those with 8 cm diameter and hybrid variants, acquired similar numeric names with even larger deviation (Sony Vaio VGN-FZ31S battery) .

The 12 cm type is a standard DVD, and the 8 cm variety is known as a MiniDVD. These are the same sizes as a standard CD and amini-CD, respectively. The capacity by surface (MiB/cm²) varies from 6.92 MiB/cm² in the DVD-1 to 18.0 MiB/cm² in the DVD-18.

As with hard disk drives, in the DVD realm, gigabyte and the symbol GB are usually used in the SI sense (i.e., 10⁹, or 1,000,000,000 bytes). For distinction, gibibyte (with symbol GiB) is used (i.e., 2³⁰, or 1,073,741,824 bytes) (Sony Vaio VGN-FZ31S battery) .

Size comparison: a 12 cm DVD+RW and a 19 cm pencil.

Each DVD sector contains 2,418 bytes of data, 2,048 bytes of which are user data. There is a small difference in storage space between+ and - (hyphen) formats (Hp pavilion dv6000 battery) :

Capacity differences of writable DVD formats
Type	Sectors	Bytes	KB	MB	GB	KiB	MiB	GiB
DVD-R SL	2,298,496	4,707,319,808	4,707,319.808	4,707.320	4.707	4,596,992	4,489.250	4.384
DVD+R SL	2,295,104	4,700,372,992	4,700,372.992	4,700.373	4.700	4,590,208	4,482.625	4.378
DVD-R DL	4,171,712	8,543,666,176	8,543,666.176	8,543.666	8.544	8,343,424	8,147.875	7.957
DVD+R DL	4,173,824	8,547,991,552	8,547,991.552	8,547.992	8.548	8,347,648	8,152.000	7.961

Technology

DVD uses 650 nm wavelength laser diode light as opposed to 780 nm for CD. This permits a smaller pit to be etched on the media surface compared to CDs (0.74 µm for DVD versus 1.6 µm for CD), allowing for a DVD's increased storage capacity.

In comparison, Blu-ray Disc, the successor to the DVD format, uses a wavelength of 405 nm, and one dual-layer disc has a 50 GB storage capacity (Sony VGN-FW11S Battery) .

Writing speeds for DVD were 1×, that is, 1350 kB/s (1,318 KiB/s), in the first drives and media models. More recent models, at 18× or 20×, have 18 or 20 times that speed. Note that for CD drives, 1× means 153.6 kB/s (150 KiB/s), approximately one ninth as fast.^[21]

DVD drive speeds
Drive speed	Data rate			~Write time (min)[23]
	(Mbit/s)	(MB/s)	(MiB/s)	SL	DL
1×	10.80	1.35	1.29	61	107
2×	21.60	2.70	2.57	31	54
2.4×	25.92	3.24	3.09	25	45
2.6×	28.08	3.51	3.35	23	41
4×	43.20	5.40	5.15	15	27
6×	64.80	8.10	7.72	10	18
8×	86.40	10.80	10.30	8	13
10×	108.00	13.50	12.87	6	11
12×	129.60	16.20	15.45	5	9
16×	172.80	21.60	20.60	4	7
18×	194.40	24.30	23.17	3	6
20×	216.00	27.00	25.75	3	5
22×	237.60	29.70	28.32	3	5
24×	259.20	32.40	30.90	3	4

Internal mechanism of a drive

Internal mechanism of a DVD-ROM Drive. See text for details (Sony VGP-BPS13A/B Battery) .

This mechanism is shown right side up; the disc is above it. The laser and optical system "looks at" the underside of the disc.

With reference to the photo, just to the right of image center is the disc spin motor, a gray cylinder, with its gray centering hub and black resilient drive ring on top. A clamp (not in the photo, retained in the drive's cover), pulled down by a magnet, clamps the disc when this mechanism rises, after the disc tray stops moving inward. This motor has an external rotor – every part of it that you can see spins (Sony VGP-BPS13B/B Battery) .

The gray metal chassis is shock-mounted at its four corners to reduce sensitivity to external shocks, and to reduce drive noise when running fast. The soft shock mount grommets are just below the brass-colored washers at the four corners (the left one is obscured). Running through those grommets are screws to fasten them to the black plastic frame that's underneath (Toshiba Satellite P10 Battery) .

Two parallel precision guide rods that run between upper left and lower right in the photo carry the "sled", the moving optical read-write head. As shown, this "sled" is close to, or at the position where it reads or writes at the edge of the disc.

A dark gray disc with two holes on opposite sides has a blue lens surrounded by silver-colored metal. This is the lens that's closest to the disc; it serves to both read and write by focusing the laser light to a very small spot. It's likely that this disc rotates half a turn to position a different set of optics (the other "hole") for CDs vs. DVDs (SONY VAIO VGN-FZ210CE Battery) .

Under the disc is an ingenious actuator comprising permanent magnets and coils that move the lens up and down to maintain focus on the data layer. As well, the actuator moves the lens slightly toward and away from the spin-motor spindle to keep the spot on track. Both focus and tracking are relatively quite fast and very precise. The same actuator rotates the lens mount half.a turn as described (SONY VAIO VGN-FZ38M Battery) .

To select tracks (or files) as well as advancing the "sled" during continuous read or write operations, a stepping motor rotates a coarse-pitch leadscrew to move the "sled" throughout its total travel range. The motor, itself, is the gray cylinder just to the left of the most-distant shock mount; its shaft is parallel to the support rods. The leadscrew, itself, is the rod with evenly-spaced darker details; these are the helical groove that engages a pin on the "sled" (SONY VAIO VGN-FZ31z Battery) .

The irregular orange material is flexible etched copper foil supported by thin sheet plastic; these are "flexible printed circuits" that connect everything to the electronics (which is not shown).

DVD recordable and rewritable

Faceplate of a DVD Drive supporting both DVD+ and DVD- formats (SONY VAIO VGN-FZ31E Battery) .

HP initially developed recordable DVD media from the need to store data for backup and transport.

DVD recordables are now also used for consumer audio and video recording. Three formats were developed: DVD-R/RW, DVD+R/RW (plus), and DVD-RAM. DVD-R is available in two formats, General (650 nm) and Authoring (635 nm), where Authoring discs may be recorded with encrypted content but General discs may not (SONY VAIO VGN-FZ31J Battery) .

Although most DVD writers can nowadays write the DVD+R/RW and DVD-R/RW formats (usually denoted by "DVD±RW" and/or the existence of both the DVD Forum logo and the DVD+RW Alliance logo), the "plus" and the "dash" formats use different writing specifications. Most DVD readers and players will play both kinds of discs, although older models can have trouble with the "plus" variants (SONY VAIO VGN-FZ31M Battery) .

Dual-layer recording

Dual-layer recording (sometimes also known as double-layer recording) allows DVD-R and DVD+R discs to store significantly more data—up to 8.54gigabytes per disc, compared with 4.7 gigabytes for single-layer discs. Along with this, DVD-DLs have slower write speeds as compared to ordinary DVDs and when played on a DVD player, a slight transition can be seen between the layers (SONY VAIO VGN-FZ31B Battery) .

DVD-R DL was developed for the DVD Forum by Pioneer Corporation;DVD+R DL was developed for the DVD+RW Alliance by Philips and Mitsubishi Kagaku Media (MKM).

A dual-layer disc differs from its usual DVD counterpart by employing a second physical layer within the disc itself. The drive with dual-layer capability accesses the second layer by shining the laser through the first semitransparent layer (SONY VGP-BPS13 Battery) .

In some DVD players, the layer change can exhibit a noticeable pause, up to several seconds.This caused some viewers to worry that their dual-layer discs were damaged or defective, with the end result that studios began listing a standard message explaining the dual-layer pausing effect on all dual-layer disc packaging (Dell Precision M70 Battery) .

DVD recordable discs supporting this technology are backward-compatible with some existing DVD players and DVD-ROM drives. Many current DVD recorders support dual-layer technology, and the price is now comparable to that of single-layer drives, although the blank media remain more expensive. The recording speeds reached by dual-layer media are still well below those of single-layer media (Acer Aspire One battery) .

There are two modes for dual-layer orientation. With Parallel Track Path (PTP), used on DVD-ROM, both layers start at the inside diameter (ID) and end at the outside diameter (OD) with the lead-out. With Opposite Track Path (OTP), used on many Digital Video Discs, the lower layer starts at the ID and the upper layer starts at the OD, where the other layer ends; they share one lead-in and one lead-out (Toshiba Satellite L305 Battery) .

However, some DVDs also use a parallel track, such as those authored episodically, as in a disc with several separate episodes of a TV series—where more often than not, the layer change is in-between titles and therefore would not need to be authored in the opposite track path fashion.

DVD-Video

Main article: DVD-Video

DVD-Video is a standard for content on DVD media (Toshiba Satellite M65 battery) .

The format went on sale in Japan on November 1, 1996, in the United States on March 1, 1997, in Europe on October 1, 1998 and in Australia on February 1, 1999.DVD became the dominant form of home video distribution in Japan when it first went on sale in 1996, but did not become the dominant form of home video distribution in the United States until June 15, 2003, when weekly DVD-Video in the United States rentals began outnumbering weekly VHS cassette rentals, reflecting the rapid adoption rate of the technology in the U.S. marketplace (Toshiba Satellite T4900 Battery) .

Currently, DVD-Video is the dominant form of home video distribution worldwide, although in Japan it was surpassed by Blu-ray Disc when Blu-ray first went on sale in Japan on March 31, 2006.

Although many resolutions and formats are supported, most consumer DVDs use either 4:3 or anamorphic 16:9 aspect ratio MPEG-2 video, stored at a resolution of 720/704×480 (NTSC) or 720/704×576 (PAL) at 29.97, 25, or 23.976 FPS (Toshiba PA3399U-2BRS battery) .

Audio is commonly stored using the Dolby Digital (AC-3) or Digital Theater System (DTS) formats, ranging from 16-bits/48 kHz to 24-bits/96 kHz format with monaural to 6.1-channel "Surround Sound" presentation, and/or MPEG-1 Layer 2 and/or LPCM Stereophonic. Although the specifications for video and audio requirements vary by global region and television system, many DVD players support all possible formats. DVD Video also supports features such as menus, selectable subtitles, multiple camera angles, and multiple audio tracks (Dell Latitude E6400 battery) .

Security

Main article: Content Scramble System

Consumer rights

The rise of filesharing and "piracy" has prompted many copyright holders to display notices on DVD packaging or displayed on screen when the content is played that warn consumers of the illegality of certain uses of the DVD. It is commonplace to include a 90 second advert warning that most forms of copying the contents is illegal. Many DVDs prevent skipping past or fast-forwarding through this warning, forcing the consumer to watch (Toshiba Satellite A200 Battery) .

Arrangements for renting and lending differ by geography. In the U.S., the right to re-sell, rent, or lend out bought DVDs is protected by the first-sale doctrine under the Copyright Act of 1976. In Europe, rental and lending rights are more limited, under a 1992 European Directive that gives copyright holders broader powers to restrict the commercial renting and public lending of DVD copies of their work (Toshiba Satellite 1200 Battery) .

DVD Audio

Main article: DVD Audio

DVD Audio is a format for delivering high fidelity audio content on a DVD. It offers many channel configuration options (from mono to 5.1 surround sound) at various sampling frequencies (up to 24-bits/192 kHz versus CDDA's 16-bits/44.1 kHz). Compared with the CD format, the much higher-capacity DVD format enables the inclusion of considerably more music (with respect to total running time and quantity of songs) and/or far higher audio quality (reflected by higher sampling rates and greater sample resolution, and/or additional channels for spatial sound reproduction) (Toshiba NB100 Battery) .

Despite DVD Audio's superior technical specifications, there is debate as to whether the resulting audio enhancements are distinguishable in typical listening environments. DVD Audio currently forms a niche market, probably due to the very sort of format war with rival standard SACD that DVD Video avoided (Toshiba Satellite M300 Battery) .

Security

Main article: Content Protection for Recordable Media

DVD Audio discs employ a DRM mechanism, called Content Protection for Prerecorded Media (CPPM), developed by the 4C group (IBM, Intel, Matsushita, and Toshiba).

Although CPPM was supposed to be much harder to crack than DVD Video's CSS, it too was eventually cracked in 2007 with the release of the dvdcpxm tool (Dell INSPIRON 1525 battery) .

The subsequent release of the libdvdcpxm library (which is based on dvdcpxm) allowed for the development of open source DVD-Audio players and ripping software, such as DVD-Audio Explorer. As a result, making 1:1 copies of DVD-Audio discs is now possible with relative ease, much like DVD-Video discs.

Improvements and succession

HD DVD and Blu-ray Disc

In 2006, two new formats called HD DVD and Blu-ray Disc were released as the successor to DVD (Dell Inspiron Mini 10 Battery) .

HD DVD competed unsuccessfully with Blu-ray Disc in the format war of 2006–2008. A dual layer HD DVD/Blu-ray Disc can store up to 30/50GB.

However, unlike previous format changes, e.g., audio tape to compact disc or VHS videotape to DVD, there is no immediate indication that production of the standard DVD will gradually wind down, as they still dominate, with around 87% of video sales and approximately one billion DVD player sales worldwide (Dell Latitude D830 Battery) .

In fact experts claim that the DVD will remain the dominant medium for at least another five years as Blu-ray technology is still in its introductory phase, write and read speeds being poor as well as the fact of necessary hardware being expensive and not readily available.

Consumers initially were also slow to adopt Blu-ray due to the cost. By 2009, 85% of stores were selling Blu-ray Discs. A high-definition television and appropriate connection cables are also required to take advantage of Blu-ray disc (Dell Studio 1735 Battery) .

Some analysts suggest that the biggest obstacle to replacing DVD is due to its installed base; a large majority of consumers are satisfied with DVDs. The DVD succeeded because it offered a compelling alternative to VHS. In addition, Blu-ray players are designed to be backward-compatible, allowing older DVDs to be played since the media are physically identical; this differed from the change from vinyl to CD and from tape to DVD, which involved a complete change in physical medium (Dell Latitude D620 Battery) .

This situation can be best compared to the changeover from 78 rpm shellac recordings to 45 rpm and 33? rpm vinyl recordings; because the medium used for the earlier format was virtually the same as the latter version (a disc on a turntable, played using a needle), phonographs continued to be built to play obsolete 78s for decades after the format was discontinued (SONY VAIO VGN-FZ150E Battery) .

Manufacturers continue to release standard DVD titles as of 2010, and the format remains the preferred one for the release of older television programs and films, with some programs such as Star Trek: The Original Seriesneeding to be re-scanned to produce a high definition version from the original film recordings (certain special effects were also updated in order to be better received in high-definition viewing) (Dell Studio 1555 Battery) .

In the case of Doctor Who, a series primarily produced on standard definition videotape between 1963 and 1989, BBC Video reportedly intends to continue issuing DVD-format releases of that series until at least November 2013 (since there would be very little increase in visual quality from upconverting the standard definition videotape masters to high definition) (Dell Latitude D610 Battery) .

Holographic Versatile Disc

The Holographic Versatile Disc (HVD) is an optical disc technology that may one day hold up to 4 terabytes (TB) of information, although the current maximum is 500GB. It employs a technique known as collinear holography.

5D DVD

The 5D DVD, being developed in the Swinburne University of Technology in Melbourne, Australia, uses a multilaser system to encode and read data on multiple layers. Disc capacities are estimated at up to 10 terabytes, and the technology could be commercially ready within ten years (Dell Inspiron 300M Battery) .

Use as backup medium

There are two considerations for a backup medium: obsolescence and durability. If the specifications of the DVD format are not preserved and there is no device that can read the medium, it might be hard to re-create devices that can read DVDs, making it very hard to retrieve the data.

Durability of DVDs is measured by how long the data may be read from the disc, assuming compatible devices exist that can read it: that is, how long the disc can be stored until data is lost (Dell Inspiron E1505 battery) .

Five factors affect durability: sealing method, reflective layer, organic dye makeup, where it was manufactured, and storage practices.

The longevity of the ability to read from a DVD+R or DVD-R, is largely dependent on manufacturing quality ranging from 2 to 15 years, and is believed to be an unreliable medium for backup unless great care is taken for storage conditions and handling (Dell RM791 battery) .

According to the Optical Storage Technology Association (OSTA), "manufacturers claim life spans ranging from 30 to 100 years for DVD, DVD-R and DVD+R discs and up to 30 years for DVD-RW, DVD+RW and DVD-RAM".

Sound card

A sound card (also known as an audio card) is a computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. Typical uses of sound cards include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education, and entertainment (games). Many computers have sound capabilities built in, while others require additional expansion cards to provide for audio capability (Dell XPS M1210 Battery) .

General characteristics

Sound cards usually feature a digital-to-analog converter (DAC), which converts recorded or generated digital data into an analog format. The output signal is connected to an amplifier, headphones, or external device using standard interconnects, such as a TRS connector or an RCA connector. If the number and size of connectors is too large for the space on the backplate the connectors will be off-board, typically using a breakout box, or an auxiliary backplate (Dell Studio XPS 1340 Battery) .

More advanced cards usually include more than one sound chip to provide for higher data rates and multiple simultaneous functionality, eg between digital sound production and synthesized sounds (usually for real-time generation of music and sound effects using minimal data and CPU time). Digital sound reproduction is usually done with multi-channel DACs, which are capable of multiple digital samples simultaneously at different pitches and volumes, or optionally applying real-time effects like filtering or distortion (Dell Studio XPS 1640 Battery) .

Multi-channel digital sound playback can also be used for music synthesis when used with a compliance, and even multiple-channel emulation. This approach has become common as manufacturers seek to simplify the design and the cost of sound cards.

Most sound cards have a line in connector for signal from a cassette tape recorder or similar sound source (Dell Vostro 1710 Battery) .

The sound card digitizes this signal and stores it (under control of appropriate matching computer software) on the computer's hard disk for storage, editing, or further processing. Another common external connector is the microphone connector, for use by a microphone or other low level input device. Input through a microphone jack can then be used by speech recognition software or for Voice over IPapplications (ASUS EEE PC900 battery) .

Sound channels and polyphony

An important characteristic of sound cards is polyphony, which is more than one distinct voice or sound playable simultaneouslyand independently, and the number of simultaneous channels. These are intended as the number of distinct electrical audio outputs, which may correspond to a speaker configuration such as 2.0 (stereo), 2.1 (stereo and sub woofer), 5.1 etc. Sometimes, the terms "voices" and "channels" are used interchangeably to indicate the degree of polyphony, not the output speaker configuration (Dell RM791 battery) .

For example, many older sound chips could accommodate three voices, but only one audio channel (ie, a single mono output) for output, requiring all voices to be mixed together. Later cards, such as the AdLib sound card, had a 9 voice polyphony and 1 mono channel as a combined output (Sony VGP-BPS13 battery) .

For some years, most PC sound cards have had multiple FM synthesis voices (typically 9 or 16) which were usually used for MIDI music. The full capabilities of advanced cards aren't often completely used; only one (mono) or two (stereo) voice(s) and channel(s) are usually dedicated to playback of digital sound samples, and playing back more than one digital sound sample usually requires a software downmix at a fixed sampling rate (Sony VGP-BPL9 battery) .

Modern low-cost integrated soundcards (ie, those built into motherboards) such as audio codecs like those meeting the AC'97 standard and even some budget expansion soundcards still work that way. They may provide more than two sound output channels (typically 5.1 or 7.1 surround sound), but they usually have no actual hardware polyphony for either sound effects or MIDI reproduction, these tasks are performed entirely in software (Sony VGP-BPL11 battery) .

This is similar to the way inexpensive softmodems perform modem tasks in software rather than in hardware).

Also, in the early days of wavetable synthesis, some sound card manufacturers advertised polyphony solely on the MIDI capabilities alone. In this case, the card's output channel is irrelevant (and typically, the card is only capable of two channels of digital sound). Instead, the polyphony measurement solely applies to the amount of MIDI instruments the sound card is capable of producing at one given time (Sony VGP-BPL15 battery) .

Today, a sound card providing actual hardware polyphony, regardless of the number of output channels, is typically referred to as a "hardware audio accelerator", although actual voice polyphony is not the sole (or even a necessary) prerequisite, with other aspects such as hardware acceleration of 3D sound, positional audio and real-time DSP effects being more important (Dell Inspiron E1505 battery) .

Since digital sound playback has become available and provided better performance than synthesis, modern soundcards with hardware polyphony don't actually use DACs with as many channels as voices. Instead, they perform voice mixing and effects processing in hardware (eventually performing digital filtering and conversions to and from the frequency domain for applying certain effects) inside a dedicated DSP (Dell Latitude E6400 battery) .

The final playback stage is performed by an external (in reference to the DSP chip(s)) DAC with significantly fewer channels than voices (e.g., 8 channels for 7.1 audio, which can be divided among 32, 64 or even 128 voices).

Color code

Connectors on the sound cards are colour coded as per the PC System Design Guide. They will also have symbols with arrows, holes and soundwaves that are associated with each jack position, the meaning of each is given below (HP Pavilion dv6000 Battery) :

Colour		Function	Connector	symbol
	Pink	Analog microphone audio input.	3.5 mm TRS	A microphone
	Light blue	Analog line level audio input.	3.5 mm TRS	An arrow going into a circle
	Lime green	Analog line level audio output for the main stereo signal (front speakers or headphones).	3.5 mm TRS	Arrow going out one side of a circle into a wave
	Brown/Dark	Analog line level audio output for a special panning,'Right-to-left speaker'.	3.5 mm TRS
	Black	Analog line level audio output for surround speakers, typically rear stereo.	3.5 mm TRS
	Orange	Analog line level audio output for center channel speaker and subwoofer	3.5 mm TRS
	Gold/Grey	Game port / MIDI	15 pin D	Arrow going out both sides into waves

History of sound cards for the IBM PC architecture

Sound cards for computers compatible with the IBM PC were very uncommon until 1988, which left the single internal PC speaker as the only way early PC software could produce sound and music (Sony Vaio VGN-FZ31S battery) .

The speaker hardware was typically limited to square waves, which fit the common nickname of "beeper". The resulting sound was generally described as "beeps and boops". Several companies, most notably Access Software, developed techniques for digital sound reproduction over the PC speaker; the resulting audio, while baldly functional, suffered from distorted output and low volume, and usually required all other processing to be stopped while sounds were played (Sony Vaio VGN-FZ31S battery) .

Other home computer models of the 1980s included hardware support for digital sound playback, or music synthesis (or both), leaving the IBM PC at a disadvantage to them when it came to multimedia applications such as music composition or gaming.

It is important to note that the initial design and marketing focuses of sound cards for the IBM PC platform were not based on gaming, but rather on specific audio applications such as music composition (AdLib Personal Music System, Creative Music System, IBM Music Feature Card) or on speech synthesis (DigispeechDS201, Covox Speech Thing, Street Electronics Echo). Not until Sierra and other game companies became involved in 1988 was there a switch toward gaming (Hp pavilion dv6000 battery) .

Hardware manufacturers

One of the first manufacturers of sound cards for the IBM PC was AdLib, who produced a card based on the Yamaha YM3812 sound chip, also known as the OPL2. The AdLib had two modes: A 9-voice mode where each voice could be fully programmed, and a less frequently used "percussion" mode with 3 regular voices producing 5 independent percussion-only voices for a total of 11 (Sony VGN-FW11S Battery) .

(The percussion mode was considered inflexible by most developers; it was used mostly by AdLib's own composition software.)

Creative Labs also marketed a sound card about the same time called the Creative Music System. Although the C/MS had twelve voices to AdLib's nine, and was a stereo card while the AdLib was mono, the basic technology behind it was based on the Philips SAA 1099 chip which was essentially a square-wave generator (Sony VGP-BPS13A/B Battery) .

It sounded much like twelve simultaneous PC speakers would have, and failed to sell well, even after Creative renamed it the Game Blaster a year later, and marketed it through Radio Shack in the US. The Game Blaster retailed for under $100 and included the hit game Silpheed (Sony VGP-BPS13B/B Battery) .

A large change in the IBM PC compatible sound card market happened with Creative Labs' introduced the Sound Blaster card. The Sound Blaster cloned the AdLib, and added a sound coprocessor for recording and play back of digital audio (likely to have been an Intel microcontroller relabeled by Creative). It was incorrectly called a "DSP" (to suggest it was a digital signal processor), a game port for adding a joystick, and capability to interface to MIDI equipment (using the game port and a special cable) (Toshiba Satellite P10 Battery) .

With more features at nearly the same price, and compatibility as well, most buyers chose the Sound Blaster. It eventually outsold the AdLib and dominated the market.

The Sound Blaster line of cards, together with the first inexpensive CD-ROM drives and evolving video technology, ushered in a new era of multimediacomputer applications that could play back CD audio, add recorded dialogue to computer games, or even reproduce motion video (albeit at much lower resolutions and quality in early days) (SONY VAIO VGN-FZ210CE Battery) .

The widespread decision to support the Sound Blaster design in multimedia and entertainment titles meant that future sound cards such as Media Vision's Pro Audio Spectrum and the Gravis Ultrasound had to be Sound Blaster compatible if they were to sell well. Until the early 2000s (by which the AC'97 audio standard became more widespread and eventually usurped the SoundBlaster as a standard due to its low cost and integration into many motherboards), Sound Blaster compatibility is a standard that many other sound cards still support to maintain compatibility with many games and applications released (SONY VAIO VGN-FZ38M Battery) .

Industry adoption

When game company Sierra On-Line opted to support add-on music hardware (instead of built-in hardware such as the PC speaker and built-in sound capabilities of the IBM PCjr and Tandy 1000), what could be done with sound and music on the IBM PC changed dramatically. Two of the companies Sierra partnered with were Roland and Adlib, opting to produce in-game music for King's Quest 4 that supported the Roland MT-32 and Adlib Music Synthesizer (SONY VAIO VGN-FZ31z Battery) .

The MT-32 had superior output quality, due in part to its method of sound synthesis as well as built-in reverb. Since it was the most sophisticated synthesizer they supported, Sierra chose to use most of the MT-32's custom features and unconventional instrument patches, producing background sound effects (eg, chirping birds, clopping horse hooves, etc.) before the Sound Blaster brought playing real audio clips to the PC entertainment world (SONY VAIO VGN-FZ31E Battery) .

Many game companies also supported the MT-32, but supported the Adlib card as an alternative because of the latter's higher market base. The adoption of the MT-32 led the way for the creation of the MPU-401/Roland Sound Canvas and General MIDI standards as the most common means of playing in-game music until the mid-1990s (SONY VAIO VGN-FZ31J Battery) .

Feature evolution

Early ISA bus soundcards were half-duplex, meaning they couldn't record and play digitized sound simultaneously, mostly due to inferior card hardware (eg, DSPs). Later, ISA cards like the SoundBlaster AWE series and Plug-and-play Soundblaster clones eventually became full-duplex and supported simultaneous recording and playback, but at the expense of using up two IRQ and DMA channels instead of one, making them no different from having two half-duplex sound cards in terms of configuration (SONY VAIO VGN-FZ31M Battery) .

Towards the end of the ISA bus' life, ISA soundcards started taking advantage of IRQ sharing, thus reducing the IRQs needed to one, but still needed two DMA channels. Many PCI bus cards do not have these limitations and are mostly full-duplex. It should also be noted that many modern PCI bus cards also do not require free DMA channels to operate.

Also, throughout the years, soundcards have evolved in terms of digital audio sampling rate (starting from 8-bit 11.025 kHz, to 32-bit, 192 kHz that the latest solutions support) (SONY VAIO VGN-FZ31B Battery) .

Along the way, some cards started offering wavetable synthesis, which provides superior MIDI synthesis quality relative to the earlier OPL-based solutions, which uses FM-synthesis. Also, some higher end cards started having their own RAM and processor for user-definable sound samples and MIDI instruments as well as to offload audio processing from the CPU (SONY VGP-BPS13 Battery) .

For years, soundcards had only one or two channels of digital sound (most notably the Sound Blaster series and their compatibles) with the exception of the E-MU card family, which had hardware support for up to 32 independent channels of digital audio. Early games and MOD-players needing more channels than a card could support had to resort to mixing multiple channels in software (Dell Precision M70 Battery) .

Even today, the tendency is still to mix multiple sound streams in software, except in products specifically intended for gamers or professional musicians, with a sensible difference in price from "software based" products. Also, in the early era of wavetable synthesis, soundcard companies would also sometimes boast about the card's polyphony capabilities in terms of MIDI synthesis

(Acer Aspire One battery) .

In this case polyphony solely refers to the amount of MIDI notes the card is capable of synthesizing simultaneously at one given time and not the amount of digital audio streams the card is capable of handling.

In regards to physical sound output, the number of physical sound channels has also increased. The first soundcard solutions were mono. Stereo sound was introduced in the early 90s, and quadraphonic sound came in the late 90s. This was shortly followed by 5.1 channel audio. The latest soundcards support up to 8 physical audio channels in the 7.1 speaker setup (Toshiba Satellite L305 Battery) .

Professional soundcards (audio interfaces)

An M-Audio professional sound card with its breakout cables.

Professional soundcards are special soundcards optimized for real-time (or at least low latency) multichannel sound recording and playback, including studio-grade fidelity. Their drivers usually follow the Audio Stream Input Output protocol for use with professional sound engineering and music software, although ASIO drivers are also available for a range of consumer-grade soundcards (Toshiba Satellite M65 battery) .

Professional soundcards are usually described as "audio interfaces", and sometimes have the form of external rack-mountable units using USB, FireWire, or an optical interface, to offer sufficient data rates. The emphasis in these products is, in general, on multiple input and output connectors, direct hardware support for multiple input and output sound channels, as well as higher sampling rates and fidelity as compared to the usual consumer soundcard (Toshiba Satellite T4900 Battery) .

In that respect, their role and intended purpose is more similar to a specialized multi-channel data recorder and real-time audio mixer and processor, roles which are possible only to a limited degree with typical consumer soundcards.

On the other hand, certain features of consumer soundcards such as support for environmental audio extensions (EAX), optimization for hardware acceleration in video games, or real-time ambience effects are secondary, nonexistent or even undesirable in professional soundcards, and as such audio interfaces are not recommended for the typical home user (Toshiba PA3399U-2BRS battery) .

The typical "consumer-grade" soundcard is intended for generic home, office, and entertainment purposes with an emphasis on playback and casual use, rather than catering to the needs of audio professionals. In response to this, Steinberg (the creators of audio recording and sequencing software, Cubase and Nuendo) developed a protocol that specified the handling of multiple audio inputs and outputs (Dell Latitude E6400 battery) .

In general, consumer grade soundcards impose several restrictions and inconveniences that would be unacceptable to an audio professional. One of a modern soundcard's purposes is to provide an AD/DA converter (analog to digital/digital to analog). However, in professional applications, there is usually a need for enhanced recording (analog to digital) conversion capabilities.

One of the limitations of consumer soundcards is their comparatively large sampling latency; this is the time it takes for the AD Converter to complete conversion of a sound sample and transfer it to the computer's main memory (Toshiba Satellite A200 Battery) .

Consumer soundcards are also limited in the effective sampling rates and bit depths they can actually manage (compare analog versus digital sound) and have lower numbers of less flexible input channels: professional studio recording use typically requires more than two channels which consumer soundcards provide, and more accessible connectors, unlike the variable mixture of internal—and sometimes virtual—and external connectors found in consumer-grade soundcards (Toshiba Satellite 1200 Battery) .

Sound devices other than expansion cards

Integrated sound hardware on PC motherboard

In 1984, the first IBM PCjr had only a rudimentary 3-voice sound synthesis chip (the SN76489) which was capable of generating three square-wave tones with variable amplitude, and a pseudo white noise channel that could generate primitive percussion sounds. The Tandy 1000, initially a clone of the PCjr, duplicated this functionality, with the Tandy TL/SL/RL models adding digital sound recording/playback capabilities (Toshiba NB100 Battery) .

In the late 1990s, many computer manufacturers began to replace plug-in soundcards with a "codec" chip (actually a combined audio AD/DA-converter) integrated into the motherboard. Many of these used Intel's AC'97 specification. Others used inexpensive ACR slot accessory cards (Toshiba Satellite M300 Battery) .

From the mid 2000s most motherboards were manufactured with integrated "real" (non-codec) soundcards, usually in the form of a custom chipset providing something akin to full Sound Blastercompatibility; this saves an expansion slot while providing the user with a (relatively) high quality soundcard (Dell INSPIRON 1525 battery) .

Integrated sound on other platforms

Various non-IBM PC compatible computers, such as early home computers like the Commodore C64 and Amiga or Apple's Macintosh, and workstations from manufacturers like Sun have had their own motherboard integrated sound devices. In some cases, most notably in those of the Commodore Amiga and the C64, they provide very advanced capabilities (as of the time of manufacture), in others they are only minimal capabilities. Some of these platforms have also had sound cards designed for their bus architectures that cannot be used in a standard PC (Dell Inspiron Mini 10 Battery) .

The custom sound chip on Amiga, named Paula, had four digital sound channels (2 for the left speaker and 2 for the right) with 8 bit resolution (although with patches, 14/15bit was accomplishable at the cost of high CPU usage) for each channel and a 6 bit volume control per channel. Sound Play back on Amiga was done by reading directly from the chip-RAM without using the main CPU (Dell Latitude D830 Battery) .

Sound cards on other platforms

The earliest known soundcard used by computers was the Gooch Synthetic Woodwind, A music device for PLATO terminals, and is widely hailed as the precursor to sound cards and MIDI. It was invented in 1972.

While many of Apple's machines come with on-board sound capabilities, their bestselling Apple II series suffered from a lack of more than minimal sound devices, all but the last model containing only a beeper that was even more limited than the one in the PC (Dell Studio 1735 Battery) .

To get around the problem, the Sweet Micro Systems company developed the Mockingboard (a name-play on mockingbird), which was essentially a sound card for the Apple II. Early Mockingboard models ranged from 3 voices in mono, while some later designs were 6 voices in stereo. Some software supported use of twoMockingboard cards which allowed 12 voice music and sound. A 12 voice, single card clone of the Mockingboard called the Phasor was also made by Applied Engineering (Dell Latitude D620 Battery) .

In late 2005 a company called ReactiveMicro.com produced a 6 voice clone called the Mockingboard v1 and also has plans to clone the Phasor and produce a hybrid card which will be user selectable between Mockingboardand Phasor modes plus support both the SC-01 or SC-02 speech synthesizers.

MSX computers also relied on sound cards to produce better quality audio (SONY VAIO VGN-FZ150E Battery) .

The card, known as Moonsound, uses a Yamaha OPL4 sound chip. Prior to the Moonsound, there were also soundcards called MSX Music and MSX Audio, which uses OPL2 and OPL3 chipsets, for the system.

USB sound "cards"

USB sound "card"

USB sound "cards" are actually external boxes that plug into the computer via USB. They are more accurately called audio interfaces rather than sound cards (Dell Studio 1555 Battery) .

The USB specification defines a standard interface, the USB audio device class, allowing a single driver to work with the various USB sound devices on the market. Cards meeting the USB 2.0 specification have sufficient data transfer capacity to support high quality sound operation if their circuit design permits (Dell Latitude D610 Battery) .

Other outboard sound devices

USB sound cards are far from the first external devices allowing a computer to record or synthesize sound. For example, devices such as the Covox Speech Thing were attached to the parallel port of an IBM PC and fed 6- or 8-bit PCM sample data to produce audio. Also, many types of professional soundcards (audio interfaces) have the form of an external FireWire or USB unit, usually for convenience and improved fidelity (Dell Inspiron 300M Battery) .

Soundcards using the PCMCIA cardbus interface were popular in the early days of portable computing when laptops and notebooks did not have onboard sound. Even today, while rare, these cardbus audio solutions are still used in some setups in which the onboard sound solution of the notebook or laptop is not up to par with the owners' expectations or requirements, and are particularly targeted at mobile DJs, with units providing separated outputs usually allow both playback and monitoring from one system (Dell Inspiron E1505 battery) .

Driver architecture

To use a sound card, the operating system (OS) typically requires a specific device driver. This is a low-level program that handles the data connections between the physical hardware and the operating system. Some operating systems include the drivers for some or all cards available, in other cases the drivers are supplied with the card itself, or are available for download (Dell RM791 battery) .

• DOS programs for the IBM PC often had to use universal middleware driver libraries (such as the HMI Sound Operating System, the Miles Audio Interface Libraries (AIL), the Miles Sound Systemetc.) which had drivers for most common sound cards, since DOS itself had no real concept of a sound card. Some card manufacturers provided (sometimes inefficient) middleware TSR-based drivers for their products (Dell XPS M1530 battery) .
• Often the driver is a Sound Blaster and AdLib emulator designed to allow their products to emulate a Sound Blaster and AdLib, and to allow games that could only use SoundBlaster or AdLib sound to work with the card. finally, some programs simply had driver/middleware source code incorporated into the program itself for the sound cards that were supported (Dell XPS M2010 battery) .
• Microsoft Windows uses drivers generally written by the sound card manufacturers. Many device manufacturers supply the drivers on their own discs or to Microsoft for inclusion on Windows installation disc. Sometimes drivers are also supplied by the individual vendors for download and installation. Bug fixes and other improvements are likely to be available faster via downloading, since CDs cannot be updated as frequently as a web or FTP site (Dell Vostro 1000 battery) .
• USB audio device class support is present from Windows 98 SE onwards. Since Microsoft's Universal Audio Architecture (UAA) initiative which supports the HD Audio, FireWire and USB audio device class standards, a universal class driver by Microsoft can be used. The driver is included with Windows Vista. For Windows XP, Windows 2000 or Windows Server 2003, the driver can be obtained by contacting Microsoft support. Almost all manufacturer-supplied drivers for such devices also include this class driver (HP Pavilion dv9000 battery) .
• A number of versions of UNIX make use of the portable Open Sound System (OSS). Drivers are seldom produced by the card manufacturer.
• Most present day Linux distributions make use of the Advanced Linux Sound Architecture (ALSA). Up until Linux kernel 2.4, OSS was the standard sound architecture for Linux, although ALSA can be downloaded, compiled and installed separately for kernels 2.2 or higher). But from kernel 2.5 onwards, ALSA was integrated into the kernel and the OSS native drivers were deprecated. Backwards compatibility with OSS-based software is maintained, however, by the use of the ALSA-OSS compatibility API and the OSS-emulation kernel modules (Sony Vaio VGN-FZ61B battery) .
• Mockingboard support on the Apple II is usually incorporated into the programs itself as many programs for the Apple II boot directly from disk. However a TSR is shipped on a disk that adds instructions to Apple Basic so users can create programs that uses the card, provided that the TSR is loaded first (Dell Precision M70 Battery) .

Computer recycling

Computer recycling or Electronic recycling is the recycling or reuse of computers or other electronics. It includes both finding another use for materials (such as donation to charity), and having systems dismantled in a manner that allows for the safe extraction of the constituent materials for reuse in other products (Dell XPS M1210 Battery) .

Reasons for recycling

Obsolete computers or other electronics are a valuable source for secondary raw materials, if treated properly; if not treated properly, they are a source of toxins and carcinogens. Rapid technology change, low initial cost, and even planned obsolescence have resulted in a fast-growing surplus of computer or other electronic components around the globe. Technical solutions are available, but in most cases a legal framework, a collection system, logistics, and other services need to be implemented before a technical solution can be applied (Dell Studio XPS 1340 Battery) .

According to the U.S. Environmental Protection Agency, an estimated 30 to 40 million surplus PCs, which it classifies under the term "hazardous household waste", will be ready for end-of-life management in each of the next few years. The U.S. National Safety Council estimates that 75% of all personal computers ever sold are now surplus electronics (Dell Studio XPS 1640 Battery) .

In 2007, the United States Environmental Protection Agency (EPA) said that more than 63 million computers in the U.S. were traded in for replacements—or they simply were discarded. Today 15 percent of electronic devices and equipment are recycled in the United States. Most electronic waste is sent to landfills or becomes incinerated, having a negative impact on the environment by releasing materials such as lead, mercury, or cadmium into the soil, groundwater, and atmosphere (Dell Vostro 1710 Battery) .

Many materials used in the construction of computer hardware can be recovered in the recycling process for use in future production. Reuse of tin, silicon, iron, aluminum, and a variety of plastics — all present in bulk in computers or other electronics — can reduce the costs of constructing new systems. In addition, components frequently contain copper, gold, and other materials valuable enough to reclaim in their own right (ASUS EEE PC900 battery) .

Computer components contain valuable elements and substances suitable for reclamation, including lead, copper, and gold. They also contain many toxic substances, such as dioxins, polychlorinated biphenyls (PCBs), cadmium, chromium, radioactive isotopes, and mercury. A typical computer monitor may contain more than 6% lead by weight, much of which is in the lead glass of the cathode ray tube (CRT) (Dell RM791 battery) .

A typical 15-inch computer monitor may contain 1.5 pounds of lead, but other monitors have been estimated as having up to 8 pounds of lead. Circuit boards contain considerable quantities of lead-tin solders and are even more likely to leach into groundwater or to create air pollution via incineration. Additionally, the processing required to reclaim the precious substances (including incineration and acid treatments) may release, generate, and synthesize further toxic byproducts (Sony VGP-BPS13 battery) .

A major computer or electronic recycling concern is export of waste to countries with lower environmental standards. Companies may find it cost-effective in the short term to sell outdated computers to less developed countries with lax regulations. It is commonly believed that a majority of surplus laptops are routed to developing nations as "dumping grounds for e-waste".The high value of working and reusable laptops, computers, and components (e.g., RAM) can help pay the cost of transportation for a large number of worthless "commodities" (Sony VGP-BPL9 battery) .

Broken monitors, obsolete circuit boards, and short-circuited transistors are difficult to spot in a containerload of used electronics.

Regulations

Europe

In Switzerland, the first electronic waste recycling system was implemented in 1991, beginning with collection of old refrigerators; over the years, all other electric and electronic devices were gradually added to the system. The established producer responsibility organization is SWICO, mainly handling information, communication, and organization technology (Sony VGP-BPL11 battery) .

The European Union implemented a similar system in February 2003, under the Waste Electrical and Electronic Equipment Directive (WEEE Directive, 2002/96/EC).

United States

Federal

The United States Congress considers a number of electronic waste bills, including the National Computer Recycling Act introduced by Congressman Mike Thompson (D-CA) (Sony VGP-BPL15 battery) .

Meanwhile, the main federal law governing solid waste is the Resource Conservation and Recovery Act of 1976. It covers only CRTs, though state regulations may differ.There are also separate laws concerning battery disposal. On March 25, 2009, the House Science and Technology Committee approved funding for research on reducing electronic waste and mitigating environmental impact, regarded by sponsor Ralph Hall (R-TX) as the first federal bill to address electronic waste directly (Dell Inspiron E1505 battery) .

State

Many states have introduced legislation concerning recycling and reuse of computers or computer parts or other electronics.Most American computer recycling legislation addresses it from within the larger electronic waste issue (Dell Latitude E6400 battery) .

In 2001, Arkansas enacted the Arkansas Computer and Electronic Solid Waste Management Act, which requires that state agencies manage and sell surplus computer equipment, establishes a computer and electronics recycling fund, and authorizes the Department of Environmental Quality to regulate and/or ban the disposal of computer and electronic equipment in Arkansas landfills (HP Pavilion dv6000 Battery) .

The recently passed Electronic Device Recycling Research and Development Act distributes grants to universities, government labs, and private industry for research in developing projects in line with e-waste recycling and refurbishment.

Asia

South Korea, Japan, and Taiwan require that sellers and manufacturers of electronics be responsible for recycling 75% of them (Sony Vaio VGN-FZ31S battery) .

Recycling methods

Consumer recycling

Consumer recycling options include donating computers directly to organizations in need, sending devices directly back to their original manufacturers, or getting components to a convenient recycler or refurbisher. The Computer Takeback Campaign and the Tech Soup Donate Hardware List are resources for locating recyclers and refurbishers (Sony Vaio VGN-FZ31S battery) .

Donation

Consumer recycling includes a variety of donation options, such as charities which may offer tax benefits. The U.S. Environmental Protection Agencymaintains a list of donation options for American consumers.

Takeback

When researching computer companies before a computer purchase, consumers can also find out if they offer recycling services. Most major computer manufacturers offer some form of recycling. At the user's request they may mail in their old computers, or arrange for pickup from the manufacturer (Hp pavilion dv6000 battery) .

Hewlett-Packard also offers free recycling, but only one of its "national" recycling programs is available nationally, rather than in one or two specific states. Hewlett-Packard also offers to pick up any computer product of any brand for a fee, and to offer a coupon against the purchase of future computers or components; it was the largest computer recycler in America in 2003, and it has recycled over 750 million pounds of electronic waste globally since 1995 (Sony VGN-FW11S Battery) .

It encourages the shared approach of collection points for consumers and recyclers to meet.

Exchange

Manufacturers often offer a free replacement service when purchasing a new PC. Dell Computers and Apple Inc. will take back old products when one buys a new one. Both refurbish and resell their own computers with a one-year warranty (Sony VGP-BPS13A/B Battery) .

Many companies purchase and recycle all brands of working and broken laptops and notebook computers, whether from individuals or corporations. Building a market for recycling of desktop computers has proven more difficult than exchange programs for laptops, smartphones, and other smaller electronics.A basic business model is to provide a seller an instant online quote based on laptop characteristics, then to send a shipping label and prepaid box to the seller, to erase, reformat, and process the laptop, and to pay rapidly by check (Sony VGP-BPS13B/B Battery) .

A majority of these companies are also generalized electronic waste recyclers as well; organizations that recycle computers exclusively include Cash For Laptops, a laptop refurbisher in Nevada that claims to be the first to buy laptops online, in 2001.

Online auction at eBay is an alternative for consumers willing to resell for cash less fees, in a complicated, self-managed, competitive environment where paid listings might not sell (Toshiba Satellite P10 Battery) .

Craigslist can be similarly risky due to forgery scams and uncertainty.Bulk laptops at a recycling affiliate, broken down into Dell, Gateway Computers,Hewlett-Packard, Sony, and other.

Corporate recycling

Businesses seeking a cost-effective way to recycle large amounts of computer equipment responsibly face a more complicated process (SONY VAIO VGN-FZ210CE Battery) .

They also have the option of contacting the manufacturers and arranging recycling options. However, in cases where the computer equipment comes from a wide variety of manufacturers, it may be more efficient to hire a third-party contractor to handle the recycling arrangements.

Early pioneering efforts to e-waste

The first major publication to report the recycling of computers and electronic waste was published on the front page of the New York Times on April 14th 1993 by columnist Steve Lohr (SONY VAIO VGN-FZ38M Battery) .

See Professional IT Asset Disposition (ITAD) firms specialize in corporate computer disposal and recycling services in compliance with local laws and regulations and also offer secure data elimination services that comply with data erasure standards. Companies that specialize in data protection and green disposal processes dispose of both data and used equipment while at the same time employing strict procedures to help improve the environment. Some companies will pick up unwanted equipment from businesses, wipe the data clean from the systems, and provide an estimate of the product’s remaining value (SONY VAIO VGN-FZ31z Battery) .

For unwanted items that still have value, these firms will buy the excess IT hardware and sell refurbished products to those seeking more affordable options than buying new.

Corporations face risks both for incompletely destroyed data and for improperly disposed computers, and according to the Resource Conservation and Recovery Act, are liable for compliance with regulations even if the recycling process is outsourced. Companies can mitigate these risks by requiring waivers of liability, audit trails, certificates of data destruction, signed confidentiality agreements, and random audits of information security (SONY VAIO VGN-FZ31E Battery) .

The National Association of Information Destruction is an international trade association for data destruction providers.

Data security

Data security is an important part of computer recycling. Federal regulations mandate that there are no information security leaks in the lifecycle of secure data; this includes its destruction and recycling (SONY VAIO VGN-FZ31J Battery) .

There are a number of federal laws and regulations, including HIPAA, Sarbanes-Oxley, FACTA, GLB, which govern the data lifecycle and require that establishments with high and low-profile data keep their data secure.Recycling computers can be dangerous when handling sensitive data, specifically to businesses storing tax records or employee information. While most people will try to wipe their hard drives clean before disposing of their old computers, only 5 percent rely on an industry specialist or a third party to completely clean the system before it's disposed of according to anIBM survey (SONY VAIO VGN-FZ31M Battery) .

Industry standards recommend a 3X overwriting process for complete protection against retrieving confidential information. This means a hard drive must be wiped three times in order to ensure the data cannot be retrieved and possibly used by others.

Reasons to destroy and recycle securely

There are ways to ensure that not only hardware is destroyed but also the private data on the hard drive. Having customer data stolen, lost, or misplaced contributes to the ever growing number of people who are affected by identity theft, which can cause corporations to lose more than just money (SONY VAIO VGN-FZ31B Battery) .

The image of a company that holds secure data, such as banks, pharmaceuticals, and credit corporations is also at risk. If a company’s public image is hurt that could cause consumers to not use their services and could cost millions in business losses and positive public relation campaigns. The cost of data breaches "var[ies] widely ranging $90 to $305 per customer record, depending on whether the breach is “low-profile” or “high-profile” and the company is in a non-regulated or highly regulated area, such as banking (SONY VGP-BPS13 Battery) .”

There is also a major backlash from the consumer if there is a data breach in a company that is supposed to be trusted to protect their private information.

Secure recycling

There are regulations that monitor the data security on end-of-life hardware. National Association for Information Destruction (NAID) “is the international trade association for companies providing information destruction services. Suppliers of products, equipment and services to destruction companies are also eligible for membership (Dell Precision M70 Battery) .

NAID's mission is to promote the information destruction industry and the standards and ethics of its member companies.” There are companies that follow the guidelines from NAID and also meet all Federal EPA and local DEP regulations.

The typical process for computer recycling aims to securely destroy hard drives while still recycling the byproduct. A typical process for effective computer recycling accomplishes the following (Acer Aspire One battery) :

1. Receive hardware for destruction in locked and securely transported vehicles
2. Shred hard drives
3. Separate all aluminum from the waste metals with an electromagnet
4. Collect and securely deliver the shredded remains to an aluminum recycling plant
5. Mold the remaining hard drive parts into aluminum ingots (Toshiba Satellite L305 Battery)

E-Cycling

The term e-cycling refers to the process of recycling the components or metals contained in used or discarded electronic equipment, otherwise known as electronic waste (e-waste). E-cyclable items include, but are not limited to: televisions, computers, microwave ovens, vacuum cleaners, telephones and cellular phones, stereos, and VCRs and DVDs. The need for e-cycling facilities has been increasing recently due to technology’s rapid rate of obsolescence (Toshiba Satellite M65 battery) .

Pros of e-cycling

Some people support e-cycling for ethical reasons. This stance can be traced to the fact that much of e-waste is dumped in developing countries, and people disagree with the environmental and human health hazards that this presents. As an example, groundwater has become so polluted in areas surrounding China’s landfills that water must be shipped in from 18 miles away (Toshiba Satellite T4900 Battery) .

By this token, e-cycling helps the environment by avoiding pollution and being a sustainable alternative to disposing of e-waste in landfills. Another benefit to e-cycling is that valuable materials are retrieved from e-waste that otherwise would have been thrown out. Supporters argue that e-cycling saves taxpayers money, as the financial responsibility would be shifted from the taxpayer to the manufacturers (Toshiba PA3399U-2BRS battery) .

In taking part in e-cycling, companies would be motivated to use fewer materials in the production process, create longer lasting products, and implement safer, more efficient recycling systems.

Criticisms of e-cycling

The critics of e-cycling are just as vocal as its advocates. According to the Reason Foundation, e-cycling will only raise the product and waste management costs of e-waste for consumers and limit innovation on the part of high-tech companies. They also believe that e-cycling facilities could unintentionally cause great harm to the environment. Additionally, critics claim that e-waste doesn’t occupy a significant portion of total waste (Dell Latitude E6400 battery) .

According to a European study, only 4% of waste is electronic. Another opposition to e-cycling is that many problems are posed in disassembly: the process is costly and dangerous because of the heavy metals of which the electronic products are composed, and as little as 1-5% of the original cost of materials can be retrieved. A final problem that people find is that identity fraud is all too common in regards to the disposal of electronic products (Toshiba Satellite A200 Battery) .

Where does e-waste really go?

A hefty criticism often lobbed at common recyclers is that people think that they are recycling their electronic waste, when in reality it is actually being exported to developing countries such as China, India, and Nigeria. It has been estimated that 90% of e-waste is not being recycled as promised. For instance, at free recycling drives, "recyclers" may not be staying true to their word but are selling e-waste overseas or to parts brokers. Studies indicate that 50-80% of the 300,000-400,000 tons of e-waste is being sent overseas, and that approximately 2 million tons per year go to U.S. landfills (Toshiba Satellite 1200 Battery) .

What's happening now: Policy issues and current efforts

Currently, pieces of government legislation and a number of grassroots efforts have contributed to the growth of e-cycling. The Electronic Waste Recycling Act was passed in California in 2003 . It requires that consumers pay an extra fee for certain types of electronics, and the collected money is then redistributed to recycling companies that are qualified to properly recycle these products (Toshiba NB100 Battery) .

It is the only state that legislates against e-waste through this kind of consumer fee, the other states' efforts focus on producer responsibility laws.

As of September, 2006, Dell developed the nation’s first completely-free recycling program, furthering the responsibilities that manufacturers are taking for e-cycling. Additional manufacturers and retailers such as Best Buy, Sony, and Samsung have also set up recycling programs (Toshiba Satellite M300 Battery) .

Another step being taken is the recyclers’ pledge of true stewardship, sponsored by the Computer TakeBack Campaign. It has been signed by numerous recyclers promising to recycle responsibly. Grassroots efforts have also played a big part in this issue, as they and other community organizations are being formed to help responsibly recycle e-waste. Other grassroots campaigns are Basel, the Computer TakeBack Campaign (co-coordinated by the Grassroots Recycling Network), and the Silicon Valley Toxics Coalition (Dell INSPIRON 1525 battery) .

Many people believe that the U.S. should be following the European Union model in regards to its management of e-waste. In this program, a directive forces manufacturers to take responsibility for e-cycling; it also demands manufacturers' mandatory take-back and places bans on exporting e-waste to developing countries. Another longer-term solution is for computers to be composed of less dangerous products (Dell Latitude D830 Battery) .

Electronic waste by country

Electronic waste is becoming an increasing part of the waste stream and efforts are being made to recycle and reduce this waste.

Basel Convention

Nations that have signed and ratified,along with nations that have signed but have not ratified the agreement (Dell Inspiron Mini 10 Battery) .

The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal, usually known simply as the Basel Convention, is an international treaty that was designed to reduce the movements of hazardous waste between nations, and specifically to prevent transfer of hazardous waste from developed to less developed countries (Dell Studio 1735 Battery) .

Of the 172 parties to the Convention, Afghanistan, Haiti, and the United States have signed the Convention but have not yet ratified it

For more details on this topic, see Waste legislation.

The United Nations Conference on Trade and Development (UNCTAD) tends to support the repair and recycling trade (Dell Latitude D620 Battery) .

Mining to produce the same metals, to meet demand for finished products in the west, also occurs in the same countries, and UNCTAD has recommended that restrictions against recycling exports be balanced against the environmental costs of recovering those materials from mining. Hard rock mining produces 45% of all toxins produced by all industries in the United States.

Greenpeace contends that residue problems are so significant that the exports of all used electronics should be banned (SONY VAIO VGN-FZ150E Battery) .

Asia

Many Asian countries have legislated, or will do so, for electronic waste recycling.

South Korea, Japan and Taiwan ensure manufacturer responsibility by demanding that they recycle 75% of their annual production (Dell Studio 1555 Battery) .

China

Chinese laws are primarily concerned with eliminating the import of e-waste. China has ratified the Basel Convention as well as the Basel Ban Amendment, officially banning the import of e-waste. In October 2008, The Chinese State Council also approved a “draft regulation on the management of electronic waste.” This regulation is intended to promote the continued use of resources through recycling and to monitor the end-of-life treatment of electronics (Dell Latitude D610 Battery) .

Under the new regulations, recycling of electronics by the consumer is mandated. It also requires the recycling of unnecessary materials discarded in the manufacturing process.

Australia

Electronic waste has been on the agenda of the Australian Federal Government since the mid 1990s. The Australian and New Zealand Environment and Conservation Council (now replaced by the Environment Protection and Heritage Council (EPHC)) was the first body to identify electrical and electronic waste as a concern (Dell Latitude E6400 battery) .

In 2002, the EPHC again declared that e-waste needed action. The Electrical Equipment Product Stewardship Sub-Group examined the issue and decided that computer and television waste were 'wastes of concern'. Since that time the television and computer industry has been working with the EPHC to identify a suitable way to manage end-of-life televisions and computers (Dell Inspiron 300M Battery) .

In November 2008 the EPHC committed to the development of a national solution to the issue of managing television and computer waste. This action culminated in the release of a package of documents designed to enable public consultation on the various options for managing end-of-life televisions and computers on 16 July 2009. The main document in the package is the Consultation Regulatory Impact Statement: Televisions and Computers (Dell Inspiron E1505 battery) .

The paper canvasses various options for managing end-of-life units and analyses the costs and benefits of each. The Consultation Paper does not have a preferred option. The preferred option will be developed by government through the public consultation process prior to the next meeting of the EPHC on 5 November 2009 in Perth where State and Federal Minister will adopt a position (Dell RM791 battery) .

A series of public meetings were held in Adelaide, Perth, Sydney and Melbourne to receive feedback to the government's proposals. The meetings occurred in late July and early August 2009.

Product Stewardship

Product Stewardship Australia (PSA)is a not-for-profit organisation established by the television industry in Australia to lead the way in developing recycling programs for e-waste in Australia, particularly televisions (Dell XPS M1530 battery) .

PSA works closely with both State and Federal Governments along with other industry associations to advance product stewardship in Australia. PSA has contributed to the development of the Consultation Regulatory Impact Statement on Televisions and Computers.

Canada

In February 2004, a fee similar to the one in California was added to the cost of purchasing new televisions, computers, and computer components in Alberta, the first of its kind in Canada (Dell XPS M2010 battery) .

Saskatchewan also implemented an electronics recycling fee in February 2007, followed by British Columbia in August 2007, Nova Scotia in February 2008,and Ontario in April 2009. In 2007, Manitoba issued the Proposed Electrical and Electronic Equipment Stewardship Regulation by which the sale of regulated products is forbidden unless covered by the stewardship program. "Products covered under this legislation include TVs, computers, laptops, and scanners (Dell Vostro 1000 battery) ."

Recycling regulation passed in Ontario in October 2004, requires producers to "either develop product stewardship plans or comply with a product stewardship program for specific products."

Europe

Some European countries implemented laws prohibiting the disposal of electronic waste in landfills in the 1990s. "This created an e-waste processing industry in Europe (HP Pavilion dv9000 battery) .”

In Switzerland, the first electronic waste recycling system was implemented in 1991, beginning with collection of old refrigerators. Over the years, all other electric and electronic devices were gradually been included in the system. Legislation followed in 1998, and since January 2005 it has been possible to return all electronic waste to the sales points and other collection points free of charge (Sony Vaio VGN-FZ61B battery) .

There are two established producer responsibility organizations: SWICO, mainly handling information, communication, and organization technology, and SENS, responsible for electrical appliances. The total amount of recycled electronic waste exceeds 10 kg per capita per year.

Additionally, the European Union has implemented several directives and regulations that place the responsibility for “recovery, reuse and recycling” on the manufacturer (Sony Vaio VGN-FZ18M battery) .

The Waste Electrical and Electronic Equipment Directive (WEEE Directive), as it is often referred to, has now been transposed in national laws in all member countries of the European Union. It was designed to make equipment manufacturers financially or physically responsible for their equipment at the end of its life, under a policy known as Extended producer responsibility (EPR) (Sony VGN-FZ21M battery) .

"Users of electrical and electronic equipment from private households should have the possibility of returning WEEE at least free of charge", and manufacturers must dispose of it in an environmentally friendly manner, by ecological disposal, reuse, or refurbishment. EPR is seen as a useful policy as it internalizes the end-of-life costs and provided a competitive incentive for companies to design equipment with fewer costs and liabilities when it reached its end of life (Dell Precision M70 Battery) .

However, the application of the WEEE Directive has been criticized for implementing the EPR concept in a collective manner, and thereby losing the competitive incentive of individual manufacturers to be rewarded for their green design. Since August 13, 2005, electronics manufacturers have become financially responsible for compliance to the WEEE Directive. Under the directive, each country recycles at least 4 kg of electronic waste per capita per year (Dell XPS M1210 Battery) .

Furthermore, the Directive should “decrease e-waste and e-waste exports.” In December 2008 a draft revision to the Directive proposed a market-based goal of 65%, which is 22 kg per capita in the case of the United Kingdom. A decision on the proposed revisions could result in a new WEEE Directive by 2012.The Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (2002/95/EC), commonly referred to as the Restriction of Hazardous Substances Directive (RoHS Directive), was also adopted in February 2003 by the European Union (Dell Vostro 1400 Battery) .

The RoHS Directive took effect on July 1, 2006, and is required to be enforced and become law in each member state. This directive restricts the use of six hazardous materials in the manufacture of various types of electronic and electrical equipment.

The Battery Directive enacted in 2006 regulates the manufacture, disposal and trade of batteries in the European Union (Dell Vostro A840 Battery).