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117-616: QuickPlay software revisions up to version 2.3 have two main components. The first component is a "Direct" function that provides instant access upon boot to music CDs , DVD movies, and MP3s stored on the hard drive . It is launched by the QuickPlay external button found on the notebook or included IR remote. QuickPlay "Direct" is possible through software on a separate partition with a custom operating system (Linux for QuickPlay 1.0 and Windows XP embedded for QuickPlay 2.3) installed. The secondary component of QuickPlay software (all versions)

234-400: A CD-DA layer. The optophone , first presented in 1931, was an early device that used light for both recording and playback of sound signals on a transparent photograph . More than thirty years later, American inventor James T. Russell has been credited with inventing the first system to record digital media on a photosensitive plate. Russell's patent application was filed in 1966, and he

351-404: A PC , is a computer designed for individual use. It is typically used for tasks such as word processing , internet browsing , email , multimedia playback, and gaming . Personal computers are intended to be operated directly by an end user , rather than by a computer expert or technician . Unlike large, costly minicomputers and mainframes , time-sharing by many people at the same time

468-494: A Red Book CD; thus, the mono source material is usually presented as two identical channels in a standard Red Book stereo track (i.e., mirrored mono ); an MP3 CD , can have audio file formats with mono sound. CD-Text is an extension of the Red Book specification for an audio CD that allows for the storage of additional text information (e.g., album name, song name, artist) on a standards-compliant audio CD. The information

585-442: A TV set or an appropriately sized computer display , and is often used as a digital photo viewer, music and video player, TV receiver, and digital video recorder. HTPCs are also referred to as media center systems or media servers . The goal is to combine many or all components of a home theater setup into one box. HTPCs can also connect to services providing on-demand movies and TV shows. HTPCs can be purchased pre-configured with

702-401: A kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done with toggle switches to enter instructions, and output was provided by front panel lamps. Practical use required adding peripherals such as keyboards, computer displays , disk drives , and printers . Micral N was the earliest commercial, non-kit microcomputer based on

819-511: A multitasking operating system . Eventually, due to the influence of the IBM PC on the personal computer market , personal computers and home computers lost any technical distinction. Business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of

936-553: A portable computer prototype called SCAMP (Special Computer APL Machine Portable) based on the IBM PALM processor with a Philips compact cassette drive, small CRT , and full function keyboard. SCAMP emulated an IBM 1130 minicomputer in order to run APL/1130. In 1973, APL was generally available only on mainframe computers, and most desktop sized microcomputers such as the Wang 2200 or HP 9800 offered only BASIC . Because SCAMP

1053-469: A touchscreen display, which can be controlled using either a stylus pen or finger. Some tablets may use a hybrid or convertible design, offering a keyboard that can either be removed as an attachment, or a screen that can be rotated and folded directly over top the keyboard. Some tablets may use desktop-PC operating system such as Windows or Linux, or may run an operating system designed primarily for tablets. Many tablet computers have USB ports, to which

1170-474: A 150-minute playing time, 44,056 Hz sampling rate, 16-bit linear resolution, and cross-interleaved Reed-Solomon coding (CIRC) error correction code —specifications similar to those later settled upon for the standard compact disc format in 1980. Technical details of Sony's digital audio disc were presented during the 62nd AES Convention, held on 13–16 March 1979, in Brussels . Sony's AES technical paper

1287-835: A 4096-color palette, stereo sound, Motorola 68000 CPU, 256 KB RAM, and 880 KB 3.5-inch disk drive, for US$ 1,295. IBM's first PC was introduced on 12 August 1981 setting what became a mass market standard for PC architecture. In 1982 The Computer was named Machine of the Year by Time magazine. Somewhat larger and more expensive systems were aimed at office and small business use. These often featured 80-column text displays but might not have had graphics or sound capabilities. These microprocessor-based systems were still less costly than time-shared mainframes or minicomputers. Workstations were characterized by high-performance processors and graphics displays, with large-capacity local disk storage, networking capability, and running under

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1404-603: A CD. VCDs are playable in dedicated VCD players, most modern DVD-Video players, personal computers, and some video game consoles. The VCD standard was created in 1993 by Sony, Philips, Matsushita , and JVC and is referred to as the White Book standard. Overall picture quality is intended to be comparable to VHS video. Poorly compressed VCD video can sometimes be of lower quality than VHS video, but VCD exhibits block artifacts rather than analog noise and does not deteriorate further with each use. 352×240 (or SIF ) resolution

1521-410: A computer that could fit on a desk was remarkably small, leading to the desktop nomenclature. More recently, the phrase usually indicates a particular style of computer case . Desktop computers come in a variety of styles ranging from large vertical tower cases to small models which can be tucked behind or rest directly beneath (and support) LCD monitors . While the term desktop often refers to

1638-557: A computer with a vertically aligned computer tower case , these varieties often rest on the ground or underneath desks. Despite this seeming contradiction, the term desktop does typically refer to these vertical tower cases as well as the horizontally aligned models which are designed to literally rest on top of desks and are therefore more appropriate to the desktop term, although both types qualify for this desktop label in most practical situations aside from certain physical arrangement differences. Both styles of these computer cases hold

1755-510: A desk, including a keyboard, a small one-line display, and printer. The Wang 2200 microcomputer of 1973 had a full-size cathode ray tube (CRT) and cassette tape storage. These were generally expensive specialized computers sold for business or scientific uses. 1974 saw the introduction of what is considered by many to be the first true personal computer, the Altair 8800 created by Micro Instrumentation and Telemetry Systems (MITS) . Based on

1872-479: A diameter of 20 cm (7.9 in) and a sound quality superior to that of the vinyl record. However, due to the unsatisfactory performance of the analog format, two Philips research engineers recommended a digital format in March 1974. In 1977, Philips then established a laboratory with the mission of creating a digital audio disc. The diameter of Philips's prototype compact disc was set at 11.5 cm (4.5 in),

1989-417: A disc played from beginning to end slows its rotation rate during playback. The program area is 86.05 cm and the length of the recordable spiral is 86.05 cm / 1.6 μm = 5.38 km. With a scanning speed of 1.2 m/s, the playing time is 74 minutes or 650 MiB of data on a CD-ROM. A disc with data packed slightly more densely is tolerated by most players (though some old ones fail). Using

2106-415: A few years before. Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of personal computers used at home. An increasingly important set of uses for personal computers relied on the ability of the computer to communicate with other computer systems, allowing interchange of information. Experimental public access to

2223-400: A former member of the task force, gives background information on the many technical decisions made, including the choice of the sampling frequency, playing time, and disc diameter. The task force consisted of around 6 persons, though according to Philips, the compact disc was "invented collectively by a large group of people working as a team". Early milestones in the launch and adoption of

2340-432: A graphics card installed. For this reason, desktop computers are usually preferred over laptops for gaming purposes. Unlike desktop computers, only minor internal upgrades (such as memory and hard disk drive) are feasible owing to the limited space and power available. Laptops have the same input and output ports as desktops, for connecting to external displays, mice, cameras, storage devices and keyboards. Laptops are also

2457-469: A graphics signal (typically, the CD+G player is hooked up to a television set or a computer monitor); these graphics are almost exclusively used to display lyrics on a television set for karaoke performers to sing along with. The CD+G format takes advantage of the channels R through W. These six bits store the graphics information. CD + Extended Graphics (CD+EG, also known as CD+XG) is an improved variant of

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2574-487: A hinged second panel containing a flat display screen. Closing the laptop protects the screen and keyboard during transportation. Laptops generally have a rechargeable battery , enhancing their portability. To save power, weight and space, laptop graphics chips are in many cases integrated into the CPU or chipset and use system RAM, resulting in reduced graphics performance when compared to desktop machines, that more typically have

2691-662: A joint task force of engineers to design a new digital audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980. After their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $ 1,000, over 400,000 CD players were sold in the United States between 1983 and 1984. By 1988, CD sales in the United States surpassed those of vinyl LPs, and, by 1992, CD sales surpassed those of prerecorded music-cassette tapes. The success of

2808-563: A joint task force of engineers to design a new digital audio disc. Led by engineers Kees Schouhamer Immink and Toshitada Doi , the research pushed forward laser and optical disc technology. After a year of experimentation and discussion, the task force produced the Red Book CD-DA standard. First published in 1980, the standard was formally adopted by the IEC as an international standard in 1987, with various amendments becoming part of

2925-408: A keyboard or mouse can be connected. Smartphones are often similar to tablet computers , the difference being that smartphones always have cellular integration. They are generally smaller than tablets, and may not have a slate form factor. The ultra-mobile PC (UMPC) is a small tablet computer . It was developed by Microsoft , Intel and Samsung , among others. Current UMPCs typically feature

3042-540: A larger screen or use with video projectors. IBM PC-compatible suitcase format computers became available soon after the introduction of the PC, with the Compaq Portable being a leading example of the type. Later models included a hard drive to give roughly equivalent performance to contemporary desktop computers. The development of thin plasma display and LCD screens permitted a somewhat smaller form factor, called

3159-453: A linear velocity of 1.2 m/s and a narrower track pitch of 1.5 μm increases the playing time to 80 minutes, and data capacity to 700 MiB. Even denser tracks are possible, with semi-standard 90 minute/800 MiB discs having 1.33 μm, and 99 minute/870 MiB having 1.26 μm, but compatibility suffers as density increases. A CD is read by focusing a 780 nm wavelength ( near infrared ) semiconductor laser through

3276-465: A little more expensive compared to desktops, as the miniaturized components for laptops themselves are expensive. Notebook computers such as the TRS-80 Model 100 and Epson HX-20 had roughly the plan dimensions of a sheet of typing paper ( ANSI A or ISO A4 ). These machines had a keyboard with slightly reduced dimensions compared to a desktop system, and a fixed LCD display screen coplanar with

3393-476: A malfunctioning CD writer . Error scanning can reliably predict data losses caused by media deterioration. Support of error scanning differs between vendors and models of optical disc drives , and extended error scanning (known as "advanced error scanning" in Nero DiscSpeed ) has only been available on Plextor and some BenQ optical drives so far, as of 2020. The digital data on a CD begins at

3510-739: A microprocessor, the Intel 8008 . It was built starting in 1972, and a few hundred units were sold. This had been preceded by the Datapoint 2200 in 1970, for which the Intel 8008 had been commissioned, though not accepted for use. The CPU design implemented in the Datapoint 2200 became the basis for x86 architecture used in the original IBM PC and its descendants. In 1973, the IBM Los Gatos Scientific Center developed

3627-481: A new naming scheme: devices without an integrated phone are called Windows Mobile Classic instead of Pocket PC, while devices with an integrated phone and a touch screen are called Windows Mobile Professional. Palmtop PCs were miniature pocket-sized computers running DOS that first came about in the late 1980s, typically in a clamshell form factor with a keyboard. Non-x86 based devices were often called palmtop computers, examples being Psion Series 3 . In later years

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3744-406: A preview of features that would later become staples of personal computers: e-mail , hypertext , word processing , video conferencing , and the mouse . The demonstration required technical support staff and a mainframe time-sharing computer that were far too costly for individual business use at the time. Early personal computers‍—‌generally called microcomputers‍—‌were often sold in

3861-615: A shared mainframe computer system was demonstrated as early as 1973 in the Community Memory project, but bulletin board systems and online service providers became more commonly available after 1978. Commercial Internet service providers emerged in the late 1980s, giving public access to the rapidly growing network. In 1991, the World Wide Web was made available for public use. The combination of powerful personal computers with high-resolution graphics and sound, with

3978-655: A television already in the home as the computer display, with low-detail blocky graphics and a limited color range, and text about 40 characters wide by 25 characters tall. Sinclair Research , a UK company, produced the ZX Series‍—;‌the ZX80 (1980), ZX81 (1981), and the ZX Spectrum ; the latter was introduced in 1982, and totaled 8 million unit sold. Following came the Commodore 64 , totaled 17 million units sold,

4095-406: A time, they are commonly connected to a local area network and run multi-user operating systems . Workstations are used for tasks such as computer-aided design , drafting and modeling, computation-intensive scientific and engineering calculations, image processing, architectural modeling, and computer graphics for animation and motion picture visual effects. Before the widespread use of PCs,

4212-460: A variation of this technique called pulse-density modulation (PDM), while Matsushita (now Panasonic ) chose pulse-width modulation (PWM), advertising it as MASH, which is an acronym derived from their patented Multi-stAge noiSe-sHaping PWM topology. The CD was primarily planned as the successor to the vinyl record for playing music, rather than as a data storage medium. However, CDs have grown to encompass other applications. In 1983, following

4329-601: A wide range of users, not just experienced electronics hobbyists who had the soldering skills to assemble a computer kit. The Apple I as delivered was still technically a kit computer, as it did not have a power supply, case, or keyboard when it was delivered to the Byte Shop. The first successfully mass-marketed personal computer to be announced was the Commodore PET after being revealed in January 1977. However, it

4446-451: A worm gear is used, a second shorter-throw linear motor, in the form of a coil and magnet, makes fine position adjustments to track eccentricities in the disk at high speed. Some CD drives (particularly those manufactured by Philips during the 1980s and early 1990s) use a swing arm similar to that seen on a gramophone. The pits and lands do not directly represent the 0s and 1s of binary data . Instead, non-return-to-zero, inverted encoding

4563-708: Is a stub . You can help Misplaced Pages by expanding it . Compact Disc The compact disc ( CD ) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. It uses the Compact Disc Digital Audio format which typically provides 74 minutes of audio on a disc. In later years, the compact disc was adapted for non-audio computer data storage purposes as CD-ROM and its derivatives. First released in Japan in October 1982,

4680-542: Is a desktop computer that generally comprises a high-performance video card , processor and RAM, to improve the speed and responsiveness of demanding video games . An all-in-one computer (also known as single-unit PCs) is a desktop computer that combines the monitor and processor within a single unit. A separate keyboard and mouse are standard input devices, with some monitors including touchscreen capability. The processor and other working components are typically reduced in size relative to standard desktops, located behind

4797-495: Is a portable computer that provides the full capabilities of a desktop computer . Such computers are currently large laptops. This class of computers usually includes more powerful components and a larger display than generally found in smaller portable computers, and may have limited battery capacity or no battery. Netbooks , also called mini notebooks or subnotebooks , were a subgroup of laptops suited for general computing tasks and accessing web-based applications . Initially,

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4914-559: Is an application run under Windows with identical functions. Newer versions of the Windows-only component (QuickPlay versions above 2.3) have additional gaming and karaoke functions. QuickPlay software versions 3.0 and newer included in notebooks shipping with Windows Vista , solely retain the Windows-only component, as the "Direct" component is no longer implemented due to unresolved compatibility issues. Instead, users must first boot Windows Vista and log into their user accounts before

5031-506: Is described in a document produced in 1980 by the format's joint creators, Sony and Philips. The document is known colloquially as the Red Book CD-DA after the color of its cover. The format is a two-channel 16-bit PCM encoding at a 44.1 kHz sampling rate per channel. Four-channel sound was to be an allowable option within the Red Book format, but has never been implemented. Monaural audio has no existing standard on

5148-466: Is most often proprietary, or free and open-source software , which is provided in ready-to-run , or binary form. Software for personal computers is typically developed and distributed independently from the hardware or operating system manufacturers. Many personal computer users no longer need to write their programs to make any use of a personal computer, although end-user programming is still feasible. This contrasts with mobile systems, where software

5265-527: Is not used with personal computers. The term home computer has also been used, primarily in the late 1970s and 1980s. The advent of personal computers and the concurrent Digital Revolution have significantly affected the lives of people. Institutional or corporate computer owners in the 1960s had to write their own programs to do any useful work with computers. While personal computer users may develop their applications, usually these systems run commercial software , free-of-charge software (" freeware "), which

5382-400: Is often available only through a manufacturer-supported channel, and end-user program development may be discouraged by lack of support by the manufacturer. Since the early 1990s, Microsoft operating systems (first with MS-DOS and then with Windows ) and Intel hardware – collectively called Wintel – have dominated the personal computer market, and today the term PC normally refers to

5499-407: Is playable in standard CD players, thus making them backward compatible. CD- MIDI is a format used to store music-performance data, which upon playback is performed by electronic instruments that synthesize the audio. Hence, unlike the original Red Book CD-DA, these recordings are not digitally sampled audio recordings. The CD-MIDI format is defined as an extension of the original Red Book . For

5616-510: Is protected by a film of lacquer normally spin coated directly on the reflective layer. The label is printed on the lacquer layer, usually by screen printing or offset printing . CD data is represented as tiny indentations known as pits , encoded in a spiral track molded into the top of the polycarbonate layer. The areas between pits are known as lands . Each pit is approximately 100  nm deep by 500 nm wide, and varies from 850 nm to 3.5  μm in length. The distance between

5733-444: Is routinely extended to 80 minutes and 700  MiB ( 734,003,200  bytes), 90 minutes 800  MiB ( 838,860,800  bytes), or 99 minutes 870  MiB ( 912,261,120  bytes) by arranging data more closely on the same-sized disc. The Mini CD has various diameters ranging from 60 to 80 millimetres (2.4 to 3.1 in); they have been used for CD singles or delivering device drivers . The CD gained rapid popularity in

5850-480: Is stored either in the lead-in area of the CD, where there are roughly five kilobytes of space available or in the subcode channels R to W on the disc, which can store about 31 megabytes. Compact Disc + Graphics is a special audio compact disc that contains graphics data in addition to the audio data on the disc. The disc can be played on a regular audio CD player, but when played on a special CD+G player, it can output

5967-408: Is used: a change from either pit to land or land to pit indicates a 1, while no change indicates a series of 0s. There must be at least two, and no more than ten 0s between each 1, which is defined by the length of the pit. This, in turn, is decoded by reversing the eight-to-fourteen modulation used in mastering the disc, and then reversing the cross-interleaved Reed–Solomon coding , finally revealing

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6084-536: The Apple I computer circuit board, which was fully prepared and contained about 30 chips. The Apple I computer differed from the other kit-style hobby computers of era. At the request of Paul Terrell , owner of the Byte Shop , Jobs and Wozniak were given their first purchase order, for 50 Apple I computers, only if the computers were assembled and tested and not a kit computer. Terrell wanted to have computers to sell to

6201-590: The Bendix G15 and LGP-30 of 1956, and the Soviet MIR series of computers developed from 1965 to 1969. By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person. The personal computer was made possible by major advances in semiconductor technology. In 1959,

6318-483: The Compact Disc + Graphics (CD+G) format. Like CD+G, CD+EG uses basic CD-ROM features to display text and video information in addition to the music being played. This extra data is stored in subcode channels R-W. Very few CD+EG discs have been published. Super Audio CD (SACD) is a high-resolution, read-only optical audio disc format that was designed to provide higher-fidelity digital audio reproduction than

6435-656: The Galaksija (1983) introduced in Yugoslavia and the Amstrad CPC series (464–6128). In the same year, the NEC PC-98 was introduced, which was a very popular personal computer that sold in more than 18 million units. Another famous personal computer, the revolutionary Amiga 1000 , was unveiled by Commodore on 23 July 1985. The Amiga 1000 featured a multitasking, windowing operating system, color graphics with

6552-624: The IBM Personal Computer incorporated the designation into its model name, the term originally described personal computers of any brand. In some contexts, PC is used to contrast with Mac, an Apple Macintosh computer. Since none of these Apple products were mainframes or time-sharing systems, they were all personal computers but not PC (brand) computers. In 1995, a CBS segment on the growing popularity of PC reported: "For many newcomers PC stands for Pain and Confusion." The "brain" [computer] may one day come down to our level [of

6669-522: The Red Book . Introduced in 1999, it was developed by Sony and Philips, the same companies that created the Red Book . SACD was in a format war with DVD-Audio , but neither has replaced audio CDs. The SACD standard is referred to as the Scarlet Book standard. Titles in the SACD format can be issued as hybrid discs; these discs contain the SACD audio stream as well as a standard audio CD layer which

6786-405: The lunchbox computer. The screen formed one side of the enclosure, with a detachable keyboard and one or two half-height floppy disk drives, mounted facing the ends of the computer. Some variations included a battery, allowing operation away from AC outlets. A laptop computer is designed for portability with clamshell design, where the keyboard and computer components are on one panel, with

6903-460: The silicon integrated circuit (IC) chip was developed by Robert Noyce at Fairchild Semiconductor , and the metal–oxide–semiconductor (MOS) transistor was developed by Mohamed Atalla and Dawon Kahng at Bell Labs . The MOS integrated circuit was commercialized by RCA in 1964, and then the silicon-gate MOS integrated circuit was developed by Federico Faggin at Fairchild in 1968. Faggin later used silicon-gate MOS technology to develop

7020-752: The vinyl revival . During the 2010s, the increasing popularity of solid-state media and music streaming services caused automakers to remove automotive CD players in favor of minijack auxiliary inputs, wired connections to USB devices and wireless Bluetooth connections. Automakers viewed CD players as using up valuable space and taking up weight which could be reallocated to more popular features, like large touchscreens. By 2021, only Lexus and General Motors were still including CD players as standard equipment with certain vehicles. CDs continued to be strong in some markets such as Japan where 132 million units were produced in 2019. The decline in CD sales has slowed in recent years; in 2021, CD sales increased in

7137-661: The "1977 trinity". Mass-market, ready-assembled computers had arrived, and allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware. In 1977 the Heath company introduced personal computer kits known as Heathkits , starting with the Heathkit H8 , followed by the Heathkit H89 in late 1979. With the purchase of the Heathkit H8 you would obtain

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7254-716: The 120 mm size was adopted. The adoption of EFM in June 1980 allowed 30 percent more playing time that would have resulted in 97 minutes for 120 mm diameter or 74 minutes for a disc as small as 100 millimetres (3.9 in). Instead, the information density was lowered by 30 percent to keep the playing time at 74 minutes. The 120 mm diameter has been adopted by subsequent formats, including Super Audio CD , DVD , HD DVD , and Blu-ray Disc. The 80-millimetre (3.1 in) diameter discs (" Mini CDs ") can hold up to 24 minutes of music or 210 MiB. The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA)

7371-496: The 1990s, quickly outselling all other audio formats in the United States by 1991, ending the market dominance of the phonograph record and the cassette tape . By 2000, the CD accounted for 92.3% of the entire market share in regard to US music sales . The CD is considered the last dominant audio format of the album era , as the rise of MP3 , iTunes , cellular ringtones , and other downloadable music formats in

7488-611: The 2000s designed as successors to the CD: the Super Audio CD (SACD) and DVD-Audio . However neither of these were adopted partly due to increased relevance of digital (virtual) music and the apparent lack of audible improvements in audio quality to most human ears. These effectively extended the CD's longevity in the music market. With the advent and popularity of Internet-based distribution of files in lossy-compressed audio formats such as MP3 , sales of CDs began to decline in

7605-502: The 2000s. For example, between 2000 and 2008, despite overall growth in music sales and one anomalous year of increase, major-label CD sales declined overall by 20%. Despite rapidly declining sales year-over-year, the pervasiveness of the technology lingered for a time, with companies placing CDs in pharmacies, supermarkets, and filling station convenience stores to target buyers less likely to be able to use Internet-based distribution. In 2012, CDs and DVDs made up only 34% of music sales in

7722-555: The 8-bit Intel 8080 Microprocessor, the Altair is widely recognized as the spark that ignited the microcomputer revolution as the first commercially successful personal computer. The computer bus designed for the Altair was to become a de facto standard in the form of the S-100 bus , and the first programming language for the machine was Microsoft's founding product, Altair BASIC . In 1976, Steve Jobs and Steve Wozniak sold

7839-405: The CD was the second optical disc technology to be invented, after the much larger LaserDisc (LD). By 2007, 200 billion CDs (including audio CDs, CD-ROMs and CD-Rs) had been sold worldwide. Standard CDs have a diameter of 120 mm (4.7 in), and are designed to hold up to 74 minutes of uncompressed stereo digital audio or about 650   MiB ( 681,574,400  bytes) of data. Capacity

7956-467: The CD's introduction, Immink and Joseph Braat presented the first experiments with erasable compact discs during the 73rd AES Convention . In June 1985, the computer-readable CD-ROM (read-only memory) and, in 1990, recordable CD-R discs were introduced. Recordable CDs became an alternative to tape for recording and distributing music and could be duplicated without degradation in sound quality. Other newer video formats such as DVD and Blu-ray use

8073-475: The DAC. Even when using high-precision components, this approach was prone to decoding errors. Another issue was jitter , a time-related defect. Confronted with the instability of DACs, manufacturers initially turned to increasing the number of bits in the DAC and using several DACs per audio channel, averaging their output. This increased the cost of CD players but did not solve the core problem. A breakthrough in

8190-451: The US for the first time since 2004, with Axios citing its rise to "young people who are finding they like hard copies of music in the digital age". It came at the same time as both vinyl and cassette reached sales levels not seen in 30 years. The RIAA reported that CD revenue made a dip in 2022, before increasing again in 2023 and overtook downloading for the first time in over a decade. In

8307-521: The US, 33.4 million CD albums were sold in the year 2022. In France in 2023, 10.5 million CDs were sold, almost double that of vinyl, but both of them represented generated 12% each of the French music industry revenues. Sony and Philips received praise for the development of the compact disc from professional organizations. These awards include: A CD is made from 1.2-millimetre (0.047 in) thick, polycarbonate plastic, and weighs 14–33 grams. From

8424-672: The United States. By 2015, only 24% of music in the United States was purchased on physical media, two thirds of this consisting of CDs; however, in the same year in Japan, over 80% of music was bought on CDs and other physical formats. In 2018, U.S. CD sales were 52 million units—less than 6% of the peak sales volume in 2000. In the UK, 32 million units were sold, almost 100 million fewer than in 2008. In 2018, Best Buy announced plans to decrease their focus on CD sales, however, while continuing to sell records, sales of which are growing during

8541-549: The Windows XP, Windows Vista, Windows 7, or Linux operating system , and low-voltage Intel Atom or VIA C7-M processors. A pocket PC is a hardware specification for a handheld-sized computer ( personal digital assistant , PDA) that runs the Microsoft Windows Mobile operating system . It may have the capability to run an alternative operating system like NetBSD or Linux . Pocket PCs have many of

8658-550: The Windows-only version of the QuickPlay software can be run. This occurs regardless of whether QuickPlay is launched externally (via a notebook button or IR remote button) when the notebook is off, or when Windows Vista is running. QuickPlay software has been replaced by the HP MediaSmart Software on HP Desktops and Notebook PC HP QuickPlay should not be confused with the QuickPlay project hosted by SourceForge . This multimedia software -related article

8775-473: The ability to be programmed in both APL and BASIC for engineers, analysts, statisticians, and other business problem-solvers. In the late 1960s such a machine would have been nearly as large as two desks and would have weighed about half a ton. Another desktop portable APL machine, the MCM/70 , was demonstrated in 1973 and shipped in 1974. It used the Intel 8008 processor. A seminal step in personal computing

8892-406: The bottom of the polycarbonate layer. The change in height between pits and lands results in a difference in the way the light is reflected. Because the pits are indented into the top layer of the disc and are read through the transparent polycarbonate base, the pits form bumps when read. The laser hits the disc, casting a circle of light wider than the modulated spiral track reflecting partially from

9009-477: The capabilities of desktop PCs . Numerous applications are available for handhelds adhering to the Microsoft Pocket PC specification, many of which are freeware . Microsoft-compliant Pocket PCs can also be used with many other add-ons like GPS receivers , barcode readers, RFID readers and cameras. In 2007, with the release of Windows Mobile 6, Microsoft dropped the name Pocket PC in favor of

9126-451: The center of the disc and proceeds toward the edge, which allows adaptation to the different sizes available. Standard CDs are available in two sizes. By far, the most common is 120 millimetres (4.7 in) in diameter, with a 74-, 80, 90, or 99-minute audio capacity and a 650, 700, 800, or 870 MiB (737,280,000-byte) data capacity. Discs are 1.2 millimetres (0.047 in) thick, with a 15 millimetres (0.59 in) center hole. The size of

9243-407: The center outward, components are: the center spindle hole (15 mm), the first-transition area (clamping ring), the clamping area (stacking ring), the second-transition area (mirror band), the program (data) area, and the rim. The inner program area occupies a radius from 25 to 58 mm. A thin layer of aluminum or, more rarely, gold is applied to the surface, making it reflective. The metal

9360-577: The chassis and CPU card to assemble yourself, additional hardware such as the H8-1 memory board that contained 4k of RAM could also be purchased in order to run software. The Heathkit H11 model was released in 1978 and was one of the first 16-bit personal computers; however, due to its high retail cost of $ 1,295 was discontinued in 1982. During the early 1980s, home computers were further developed for household use, with software for personal productivity, programming and games. They typically could be used with

9477-673: The common people] and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far. In the history of computing , early experimental machines could be operated by a single attendant. For example, ENIAC which became operational in 1946 could be run by a single, albeit highly trained, person. This mode pre-dated the batch programming, or time-sharing modes with multiple users connected through terminals to mainframe computers. Computers intended for laboratory, instrumentation, or engineering purposes were built, and could be operated by one person in an interactive fashion. Examples include such systems as

9594-450: The compact disc has been credited to the cooperation between Philips and Sony, which together agreed upon and developed compatible hardware. The unified design of the compact disc allowed consumers to purchase any disc or player from any company and allowed the CD to dominate the at-home music market unchallenged. In 1974, Lou Ottens, director of the audio division of Philips, started a small group to develop an analog optical audio disc with

9711-423: The diagonal of an audio cassette. Heitaro Nakajima , who developed an early digital audio recorder within Japan's national public broadcasting organization, NHK , in 1970, became general manager of Sony's audio department in 1971. In 1973, his team developed a digital PCM adaptor that made audio recordings using a Betamax video recorder. After this, in 1974 the leap to storing digital audio on an optical disc

9828-516: The first few years of its existence, the CD was a medium used purely for audio. In 1988, the Yellow Book CD-ROM standard was established by Sony and Philips, which defined a non-volatile optical data computer data storage medium using the same physical format as audio compact discs, readable by a computer with a CD-ROM drive. Video CD (VCD, View CD, and Compact Disc digital video) is a standard digital format for storing video media on

9945-463: The first four UK albums by the Beatles were released in mono on compact disc. The growing acceptance of the CD in 1983 marks the beginning of the popular digital audio revolution. It was enthusiastically received, especially in the early-adopting classical music and audiophile communities, and its handling quality received particular praise. As the price of players gradually came down, and with

10062-479: The first single-chip microprocessor , the Intel 4004 , in 1971. The first microcomputers , based on microprocessors, were developed during the early 1970s. Widespread commercial availability of microprocessors, from the mid-1970s onwards, made computers cheap enough for small businesses and individuals to own. In what was later to be called the Mother of All Demos , SRI researcher Douglas Engelbart in 1968 gave

10179-813: The format included: The first artist to sell a million copies on CD was Dire Straits , with their 1985 album Brothers in Arms . One of the first CD markets was devoted to reissuing popular music whose commercial potential was already proven. The first major artist to have their entire catalog converted to CD was David Bowie , whose first fourteen studio albums (up to Scary Monsters (and Super Creeps) ) of (then) sixteen were made available by RCA Records in February 1985, along with four greatest hits albums; his fifteenth and sixteenth albums ( Let's Dance and Tonight , respectively) had already been issued on CD by EMI Records in 1983 and 1984, respectively. On 26 February 1987,

10296-530: The hole was chosen by Joop Sinjou and based on a Dutch 10-cent coin: a dubbeltje . Philips/Sony patented the physical dimensions. The official Philips history says the capacity was specified by Sony executive Norio Ohga to be able to contain the entirety of Beethoven's Ninth Symphony on one disc. This is a myth according to Kees Immink , as the EFM code format had not yet been decided in December 1979, when

10413-556: The infrastructure provided by the Internet, and the standardization of access methods of the Web browsers , established the foundation for a significant fraction of modern life, from bus time tables through unlimited distribution of free videos through to online user-edited encyclopedias. A workstation is a high-end personal computer designed for technical, mathematical, or scientific applications. Intended primarily to be used by one person at

10530-519: The introduction of the IBM PC, portable computers consisting of a processor, display, disk drives and keyboard, in a suit-case style portable housing, allowed users to bring a computer home from the office or to take notes at a classroom. Examples include the Osborne 1 and Kaypro ; and the Commodore SX-64 . These machines were AC-powered and included a small CRT display screen. The form factor

10647-505: The introduction of the portable Discman , the CD began to gain popularity in the larger popular and rock music markets. With the rise in CD sales, pre-recorded cassette tape sales began to decline in the late 1980s; CD sales overtook cassette sales in the early 1990s. In 1988, 400 million CDs were manufactured by 50 pressing plants around the world. Early CD players employed binary-weighted digital-to-analog converters (DAC), which contained individual electrical components for each bit of

10764-549: The keyboard. These displays were usually small, with 8 to 16 lines of text, sometimes only 40 columns line length. However, these machines could operate for extended times on disposable or rechargeable batteries. Although they did not usually include internal disk drives, this form factor often included a modem for telephone communication and often had provisions for external cassette or disk storage. Later, clamshell format laptop computers with similar small plan dimensions were also called notebooks . A desktop replacement computer

10881-476: The label side of the disc. Scratches on the clear side can be repaired by refilling them with similar refractive plastic or by careful polishing. The edges of CDs are sometimes incompletely sealed, allowing gases and liquids to enter the CD and corrode the metal reflective layer and/or interfere with the focus of the laser on the pits, a condition known as disc rot . The fungus Geotrichum candidum has been found—under conditions of high heat and humidity—to consume

10998-510: The lands and partially from the top of any bumps where they are present. As the laser passes over a pit (bump), its height means that the round trip path of the light reflected from its peak is 1/2 wavelength out of phase with the light reflected from the land around it. This is because the height of a bump is around 1/4 of the wavelength of the light used, so the light falls 1/4 out of phase before reflection and another 1/4 wavelength out of phase after reflection. This causes partial cancellation of

11115-419: The laser's reflection from the surface. By measuring the reflected intensity change with a photodiode , a modulated signal is read back from the disc. To accommodate the spiral pattern of data, the laser is placed on a mobile mechanism within the disc tray of any CD player. This mechanism typically takes the form of a sled that moves along a rail. The sled can be driven by a worm gear or linear motor . Where

11232-428: The late 1980s culminated in development of the 1-bit DAC , which converts high-resolution low-frequency digital input signal into a lower-resolution high-frequency signal that is mapped to voltages and then smoothed with an analog filter. The temporary use of a lower-resolution signal simplified circuit design and improved efficiency, which is why it became dominant in CD players starting from the early 1990s. Philips used

11349-557: The mid-2000s ended the decade-long dominance of the CD. The format was later adapted (as CD-ROM ) for general purpose data storage and initially could hold much more data than a personal computer hard disk drive . Several other formats were further derived, both pre-pressed and blank user writable, including write-once audio and data storage ( CD-R ), rewritable media ( CD-RW ), Video CD (VCD), Super Video CD (SVCD), Photo CD , Picture CD , Compact Disc-Interactive ( CD-i ), Enhanced Music CD , and Super Audio CD (SACD) which may have

11466-399: The monitor, and configured similarly to laptops. A nettop computer was introduced by Intel in February 2008, characterized by low cost and lean functionality. These were intended to be used with an Internet connection to run Web browsers and Internet applications. A Home theater PC (HTPC) combines the functions of a personal computer and a digital video recorder . It is connected to

11583-536: The polycarbonate plastic and aluminium found in CDs. The data integrity of compact discs can be measured using surface error scanning , which can measure the rates of different types of data errors, known as C1 , C2 , CU and extended (finer-grain) error measurements known as E11 , E12 , E21 , E22 , E31 and E32 , of which higher rates indicate a possibly damaged or unclean data surface, low media quality, deteriorating media and recordable media written to by

11700-503: The primary defining characteristic of netbooks was the lack of an optical disc drive, smaller size, and lower performance than full-size laptops. By mid-2009 netbooks had been offered to users "free of charge", with an extended service contract purchase of a cellular data plan. Ultrabooks and Chromebooks have since filled the gap left by Netbooks. Unlike the generic Netbook name, Ultrabook and Chromebook are technically both specifications by Intel and Google respectively. A tablet uses

11817-507: The prior art by Optophonie and James Russell, the information on the disc is read from a reflective layer using a laser as a light source through a protective substrate. Prototypes were developed by Philips and Sony independently in the late 1970s. Although originally dismissed by Philips Research management as a trivial pursuit, the CD became the primary focus for Philips as the LaserDisc format struggled. In 1979, Sony and Philips set up

11934-543: The raw data stored on the disc. These encoding techniques (defined in the Red Book ) were originally designed for CD Digital Audio , but they later became a standard for almost all CD formats (such as CD-ROM ). CDs are susceptible to damage during handling and from environmental exposure. Pits are much closer to the label side of a disc, enabling defects and contaminants on the clear side to be out of focus during playback. Consequently, CDs are more likely to suffer damage on

12051-498: The required hardware and software needed to add television programming to the PC, or can be assembled from components. Keyboard computers are computers inside of keyboards, generally still designed to be connected to an external computer monitor or television . Examples include the Atari ST , Amstrad CPC , BBC Micro , Commodore 64 , MSX , Raspberry Pi 400 , and the ZX Spectrum . The potential utility of portable computers

12168-432: The same physical geometry as CD, and most DVD and Blu-ray players are backward compatible with audio CDs. CD sales in the United States peaked by 2000. By the early 2000s, the CD player had largely replaced the audio cassette player as standard equipment in new automobiles, with 2010 being the final model year for any car in the United States to have a factory-equipped cassette player. Two new formats were marketed in

12285-511: The standard in 1996. Philips coined the term compact disc in line with another audio product, the Compact Cassette , and contributed the general manufacturing process , based on video LaserDisc technology. Philips also contributed eight-to-fourteen modulation (EFM), while Sony contributed the error-correction method, CIRC, which offers resilience to defects such as scratches and fingerprints. The Compact Disc Story , told by

12402-418: The systems hardware components such as the motherboard , processor chip and other internal operating parts. Desktop computers have an external monitor with a display screen and an external keyboard, which are plugged into ports on the back of the computer case. Desktop computers are popular for home and business computing applications as they leave space on the desk for multiple monitors . A gaming computer

12519-572: The ubiquitous Wintel platform. Alternatives to Windows occupy a minority share of the market; these include the Mac platform from Apple (running the macOS operating system), and free and open-source , Unix-like operating systems, such as Linux . Other notable platforms until the 1990s were the Amiga from Commodore , and the PC-98 from NEC . The term PC is an initialism for personal computer. While

12636-420: The windings (the pitch ) is 1.6 μm (measured center-to-center, not between the edges). When playing an audio CD, a motor within the CD player spins the disc to a scanning velocity of 1.2–1.4 m/s ( constant linear velocity , CLV)—equivalent to approximately 500 RPM at the inside of the disc, and approximately 200 RPM at the outside edge. The track on the CD begins at the inside and spirals outward so

12753-508: Was apparent early on. Alan Kay described the Dynabook in 1972, but no hardware was developed. The Xerox NoteTaker was produced in a very small experimental batch around 1978. In 1975, the IBM 5100 could be fit into a transport case, making it a portable computer, but it weighed about 50 pounds. Such early portable computers were termed luggables by journalists owing to their heft. Before

12870-705: Was back-ordered and not available until later that year. Three months later (April), the Apple II (usually referred to as the Apple) was announced with the first units being shipped 10 June 1977, and the TRS-80 from Tandy Corporation / Tandy Radio Shack following in August 1977, which sold over 100,000 units during its lifetime. Together, especially in the North American market, these 3 machines were referred to as

12987-450: Was chosen because it is half the vertical and half the horizontal resolution of the NTSC video. 352×288 is a similarly one-quarter PAL/SECAM resolution. This approximates the (overall) resolution of an analog VHS tape, which, although it has double the number of (vertical) scan lines, has a much lower horizontal resolution. Personal computer A personal computer , often referred to as

13104-464: Was easily made. Sony first publicly demonstrated an optical digital audio disc in September 1976. A year later, in September 1977, Sony showed the press a 30 cm (12 in) disc that could play an hour of digital audio (44,100 Hz sampling rate and 16-bit resolution) using modified frequency modulation encoding. In September 1978, the company demonstrated an optical digital audio disc with

13221-461: Was granted a patent in 1970. Following litigation, Sony and Philips licensed Russell's patents for recording in 1988. It is debatable whether Russell's concepts, patents, and prototypes instigated and in some measure influenced the compact disc's design. The compact disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Unlike

13338-401: Was intended to allow these systems to be taken on board an airplane as carry-on baggage, though their high power demand meant that they could not be used in flight. The integrated CRT display made for a relatively heavy package, but these machines were more portable than their contemporary desktop equals. Some models had standard or optional connections to drive an external video monitor, allowing

13455-514: Was published on 1 March 1979. A week later, on 8 March, Philips publicly demonstrated a prototype of an optical digital audio disc at a press conference called "Philips Introduce Compact Disc" in Eindhoven , Netherlands. Sony executive Norio Ohga , later CEO and chairman of Sony, and Heitaro Nakajima were convinced of the format's commercial potential and pushed further development despite widespread skepticism. In 1979, Sony and Philips set up

13572-453: Was the 1973 Xerox Alto , developed at Xerox 's Palo Alto Research Center (PARC) . It had a graphical user interface ( GUI ) which later served as inspiration for Apple's Macintosh , and Microsoft's Windows operating system. The Alto was a demonstration project, not commercialized, as the parts were too expensive to be affordable. Also in 1973 Hewlett Packard introduced fully BASIC programmable microcomputers that fit entirely on top of

13689-500: Was the first to emulate APL/1130 performance on a portable, single user computer, PC Magazine in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer". This seminal, single user portable computer now resides in the Smithsonian Institution , Washington, D.C.. Successful demonstrations of the 1973 SCAMP prototype led to the IBM 5100 portable microcomputer launched in 1975 with

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