1.
Motherboard
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A motherboard is the main printed circuit board found in general purpose microcomputers and other expandable systems. It holds and allows communication between many of the electronic components of a system, such as the central processing unit and memory. In very old designs, copper wires were the discrete connections between card connector pins, but printed circuit boards soon became the standard practice, the Central Processing Unit, memory, and peripherals were housed on individual printed circuit boards, which were plugged into the backplate. The ubiquitous S-100 bus of the 1970s is an example of type of backplane system. During the late 1980s and 1990s, it became economical to move a number of peripheral functions onto the motherboard. Business PCs, workstations, and servers were more likely to need expansion cards, either for more robust functions, or for higher speeds, laptop and notebook computers that were developed in the 1990s integrated the most common peripherals. This even included motherboards with no upgradeable components, a trend that would continue as smaller systems were introduced after the turn of the century, memory, processors, network controllers, power source, and storage would be integrated into some systems. A motherboard provides the connections by which the other components of the system communicate. Unlike a backplane, it contains the central processing unit and hosts other subsystems. A typical desktop computer has its microprocessor, main memory, an important component of a motherboard is the microprocessors supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard, modern motherboards include, Sockets in which one or more microprocessors may be installed. In the case of CPUs in ball grid array packages, such as the VIA C3, as of 2007, some graphics cards require more power than the motherboard can provide, and thus dedicated connectors have been introduced to attach them directly to the power supply. Connectors for hard drives, typically SATA only, disk drives also connect to the power supply. Additionally, nearly all motherboards include logic and connectors to support commonly used devices, such as USB for mouse devices. Early personal computers such as the Apple II or IBM PC included only this minimal peripheral support on the motherboard, occasionally video interface hardware was also integrated into the motherboard, for example, on the Apple II and rarely on IBM-compatible computers such as the IBM PC Jr. Additional peripherals such as disk controllers and serial ports were provided as expansion cards, given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat. Motherboards are produced in a variety of sizes and shapes called computer form factor, however, the motherboards used in IBM-compatible systems are designed to fit various case sizes. As of 2007, most desktop computer motherboards use the ATX standard form factor — even those found in Macintosh and Sun computers, a cases motherboard and PSU form factor must all match, though some smaller form factor motherboards of the same family will fit larger cases
2.
IBM
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International Business Machines Corporation is an American multinational technology company headquartered in Armonk, New York, United States, with operations in over 170 countries. The company originated in 1911 as the Computing-Tabulating-Recording Company and was renamed International Business Machines in 1924, IBM manufactures and markets computer hardware, middleware and software, and offers hosting and consulting services in areas ranging from mainframe computers to nanotechnology. IBM is also a research organization, holding the record for most patents generated by a business for 24 consecutive years. IBM has continually shifted its business mix by exiting commoditizing markets and focusing on higher-value, also in 2014, IBM announced that it would go fabless, continuing to design semiconductors, but offloading manufacturing to GlobalFoundries. Nicknamed Big Blue, IBM is one of 30 companies included in the Dow Jones Industrial Average and one of the worlds largest employers, with nearly 380,000 employees. Known as IBMers, IBM employees have been awarded five Nobel Prizes, six Turing Awards, ten National Medals of Technology, in the 1880s, technologies emerged that would ultimately form the core of what would become International Business Machines. On June 16,1911, their four companies were amalgamated in New York State by Charles Ranlett Flint forming a fifth company, the Computing-Tabulating-Recording Company based in Endicott, New York. The five companies had 1,300 employees and offices and plants in Endicott and Binghamton, New York, Dayton, Ohio, Detroit, Michigan, Washington, D. C. and Toronto. They manufactured machinery for sale and lease, ranging from commercial scales and industrial time recorders, meat and cheese slicers, to tabulators and punched cards. Thomas J. Watson, Sr. fired from the National Cash Register Company by John Henry Patterson, called on Flint and, Watson joined CTR as General Manager then,11 months later, was made President when court cases relating to his time at NCR were resolved. Having learned Pattersons pioneering business practices, Watson proceeded to put the stamp of NCR onto CTRs companies and his favorite slogan, THINK, became a mantra for each companys employees. During Watsons first four years, revenues more than doubled to $9 million, Watson had never liked the clumsy hyphenated title of the CTR and in 1924 chose to replace it with the more expansive title International Business Machines. By 1933 most of the subsidiaries had been merged into one company, in 1937, IBMs tabulating equipment enabled organizations to process unprecedented amounts of data, its clients including the U. S. During the Second World War the company produced small arms for the American war effort, in 1949, Thomas Watson, Sr. created IBM World Trade Corporation, a subsidiary of IBM focused on foreign operations. In 1952, he stepped down after almost 40 years at the company helm, in 1957, the FORTRAN scientific programming language was developed. In 1961, IBM developed the SABRE reservation system for American Airlines, in 1963, IBM employees and computers helped NASA track the orbital flight of the Mercury astronauts. A year later it moved its headquarters from New York City to Armonk. The latter half of the 1960s saw IBM continue its support of space exploration, on April 7,1964, IBM announced the first computer system family, the IBM System/360
3.
Conventional PCI
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Conventional PCI, often shortened to PCI, is a local computer bus for attaching hardware devices in a computer. PCI is the initialism for Peripheral Component Interconnect and is part of the PCI Local Bus standard, the PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any particular processors native bus. Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the address space. It is a bus, synchronous to a single bus clock. Attached devices can take either the form of an integrated circuit fitted onto the motherboard itself or a card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles and it has subsequently been adopted for other computer types. Typical PCI cards used in PCs include, network cards, sound cards, modems, extra ports such as USB or serial, TV tuner cards, PCI video cards replaced ISA and VESA cards until growing bandwidth requirements outgrew the capabilities of PCI. The preferred interface for video cards then became AGP, itself a superset of conventional PCI and these have one locating notch in the card. Version 2.0 of the PCI standard introduced 3.3 V slots, universal cards, which can operate on either voltage, have two notches. Version 2.1 of the PCI standard introduced optional 66 MHz operation, a server-oriented variant of conventional PCI, called PCI-X operated at frequencies up to 133 MHz for PCI-X1.0 and up to 533 MHz for PCI-X2.0. An internal connector for laptop cards, called Mini PCI, was introduced in version 2.2 of the PCI specification, the PCI bus was also adopted for an external laptop connector standard – the CardBus. The first PCI specification was developed by Intel, but subsequent development of the standard became the responsibility of the PCI Special Interest Group, Conventional PCIs heyday in the desktop computer market was approximately 1995–2005. PCI and PCI-X have become obsolete for most purposes, however, they are common on modern desktops for the purposes of backwards compatibility. Many kinds of devices available on PCI expansion cards are now commonly integrated onto motherboards or available in USB. Work on PCI began at Intels Architecture Development Lab c. 1990, a team of Intel engineers defined the architecture and developed a proof of concept chipset and platform partnering with teams in the companys desktop PC systems and core logic product organizations. PCI was immediately put to use in servers, replacing MCA, in mainstream PCs, PCI was slower to replace VESA Local Bus, and did not gain significant market penetration until late 1994 in second-generation Pentium PCs. By 1996, VLB was all but extinct, and manufacturers had adopted PCI even for 486 computers, EISA continued to be used alongside PCI through 2000. Apple Computer adopted PCI for professional Power Macintosh computers in mid-1995, the 64-bit version of plain PCI remained rare in practice though, although it was used for example by all G3 and G4 Power Macintosh computers
4.
Accelerated Graphics Port
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The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer system, primarily to assist in the acceleration of 3D computer graphics. It was originally designed as a successor to PCI-type connections for video cards, since 2004, AGP has been progressively phased out in favor of PCI Express, by mid-2008, PCI Express cards dominated the market and only a few AGP models were available. As computers increasingly became graphically oriented, successive generations of graphics adapters began to push the limits of PCI and this led to the development of AGP, a bus dedicated to graphics adapters. AGP is heavily based on PCI, and in fact the AGP bus is a superset of the conventional PCI bus, the primary advantage of AGP over PCI is that it provides a dedicated pathway between the slot and the processor rather than sharing the PCI bus. In addition to a lack of contention for the bus, the direct connection allows for higher clock speeds, the second major change is that AGP uses split transactions, where the address and data phases of a PCI transaction are separated. The card may send many address phases, and the host processes them in order and this avoids long delays, with the bus idle, during read operations. Third, PCI bus handshaking is simplified, further, rather than using the IRDY# and TRDY# signals for each word, data is transferred in blocks of four clock cycles, and pauses are allowed only between blocks. Finally, AGP allows sideband addressing, meaning that the address and this is done by adding an extra 8-bit SideBand Address bus over which the graphics controller can issue new AGP requests while other AGP data is flowing over the main 32 address/data lines. This results in improved overall AGP data throughput, system memory is made available using the graphics address remapping table, which apportions main memory as needed for texture storage. The maximum amount of memory available to AGP is defined as the AGP aperture. The AGP slot first appeared on x86-compatible system boards based on Socket 7 Intel P5 Pentium, Intel introduced AGP support with the i440LX Slot 1 chipset on August 26,1997, and a flood of products followed from all the major system board vendors. The first Socket 7 chipsets to support AGP were the VIA Apollo VP3, SiS 5591/5592, Intel never released an AGP-equipped Socket 7 chipset. Some early AGP boards used graphics processors built around PCI and were bridged to AGP. This resulted in the cards benefiting little from the new bus, with the only improvement used being the 66 MHz bus clock, with its resulting doubled bandwidth over PCI, examples of such cards were the Voodoo Banshee, Vérité V2200, Millennium II, and S3 ViRGE GX/2. Intels i740 was explicitly designed to exploit the new AGP feature set, after applying the patch the Windows 95 system became Windows 95 version 4.00.950 B. The first Windows NT-based operating system to receive AGP support was Windows NT4.0 with Service Pack 3, linux support for AGP enhanced fast data transfers was first added in 1999 with the implementation of the AGPgart kernel module. Intel released AGP specification 1.0 in 1997 and it specified 3.3 V signals and 1× and 2× speeds. Specification 2.0 documented 1.5 V signaling, which could be used at 1×, 2× and the additional 4× speed and 3.0 added 0.8 V signaling, available versions are listed in the table on the right
5.
Retronym
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A retronym is a neologism for a word created to differentiate between two words, where previously no clarification was required. Advances in technology are responsible for the coinage of retronyms. For example, the acoustic guitar was coined at the advent of electric guitars. Since the end of the 19th century, most bicycles have been expected to have two equal sized wheels, and the type has been renamed penny-farthing or high-wheeler bicycle. Similarly, the term cisgender was coined to describe persons who identify with the gender they were assigned at birth, the term retronym was coined by Frank Mankiewicz in 1980 and popularized by William Safire in The New York Times Magazine. In 2000 The American Heritage Dictionary became the first major dictionary to include the word retronym, back-formation Backronym Contrastive focus reduplication -onym Protologism
6.
Bus (computing)
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In computer architecture, a bus is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related components and software, including communication protocols. Modern computer buses can use both parallel and bit serial connections, and can be wired in either a multidrop or daisy chain topology, or connected by switched hubs, as in the case of USB. An early computer might contain a hand-wired CPU of vacuum tubes, a drum for main memory. In both examples, computer buses of one form or another move data between all of these devices, in most traditional computer architectures, the CPU and main memory tend to be tightly coupled. In most cases, the CPU and memory share signalling characteristics, the bus connecting the CPU and memory is one of the defining characteristics of the system, and often referred to simply as the system bus. It is possible to allow peripherals to communicate with memory in the same fashion and this is commonly accomplished through some sort of standardized electrical connector, several of these forming the expansion bus or local bus. However, as the differences between the CPU and peripherals varies widely, some solution is generally needed to ensure that peripherals do not slow overall system performance. Many CPUs feature a set of pins similar to those for communicating with memory. Others use smart controllers to place the data directly in memory, most modern systems combine both solutions, where appropriate. As the number of potential peripherals grew, using a card for every peripheral became increasingly untenable. This has led to the introduction of bus systems designed specifically to support multiple peripherals, common examples are the SATA ports in modern computers, which allow a number of hard drives to be connected without the need for a card. However, these systems are generally too expensive to implement in low-end devices. This has led to the development of a number of low-performance bus systems for these solutions. All such examples may be referred to as peripheral buses, although this terminology is not universal, in modern systems the performance difference between the CPU and main memory has grown so great that increasing amounts of high-speed memory is built directly into the CPU, known as a cache. These system buses are used to communicate with most other peripherals, through adaptors. Such systems are more similar to multicomputers, communicating over a bus rather than a network. In these cases, expansion buses are entirely separate and no longer share any architecture with their host CPU, what would have formerly been a system bus is now often known as a front-side bus
7.
Intel 80286
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The Intel 80286 is a 16-bit microprocessor that was introduced on 1 February 1982. It was the first 8086 based CPU with separate, non-multiplexed, address and data buses and also the first with memory management, the 80286 was employed for the IBM PC/AT, introduced in 1984, and then widely used in most PC/AT compatible computers until the early 1990s. Although now long since obsolete for use in computers,80286 based processors are still widely used in embedded microcontroller applications. Intels first 80286 chips were specified for a maximum clockrate of 4,6 or 8 MHz, AMD and Harris later produced 16 MHz,20 MHz and 25 MHz parts, respectively. Intersil and Fujitsu also designed fully static CMOS versions of Intels original depletion-load nMOS implementation, the 6 MHz,10 MHz and 12 MHz models were reportedly measured to operate at 0.9 MIPS,1.5 MIPS and 2.66 MIPS respectively. The later E-stepping level of the 80286 was free of the several significant errata that caused problems for programmers, the 80286 was designed for multi-user systems with multitasking applications, including communications and real-time process control. It had 134,000 transistors and consisted of four independent units, address unit, bus unit, instruction unit, the significantly increased performance over the 8086 was primarily due to the non-multiplexed address and data buses, more address calculation hardware and a faster multiplier. It was produced in a 68-pin package including PLCC, LCC, the performance increase of the 80286 over the 8086 could be more than 100% per clock cycle in many programs. This was an increase, fully comparable to the speed improvements around a decade later when the i486 or the original Pentium were introduced. This was partly due to the address and data buses. They were performed by a unit in the 80286 while the older 8086 had to do effective address computation using its general ALU. Also, the 80286 was more efficient in the prefetch of instructions, buffering, execution of jumps, together with contemporary 80186,286 added new instructions, ENTER, LEAVE, BOUND, INS, OUTS, PUSHA, POPA, PUSH immediate, IMUL immediate, multi-bit shifts. The intel 80286 had a 24-bit address bus and was able to address up to 16 MB of RAM, however cost and initial rarity of software using the memory above 1 MB meant that 80286 computers were rarely shipped with more than one megabyte of RAM. Additionally, there was a performance penalty involved in accessing extended memory from real mode, the 286 was the first of the x86 CPU family to support protected mode. In addition, it was the first commercially available microprocessor with on-chip MMU capabilities and this would allow IBM compatibles to have advanced multitasking OSes for the first time and compete in the Unix-dominated server/workstation market. Several additional instructions were introduced in protected mode of 80286, which are helpful for multitasking operating systems, another important feature of 80286 is Prevention of Unauthorized Access. This is achieved by, Forming different segments for data, code, and stack, segment with lower privilege level cannot access the segment with higher privilege level. By design, the 286 could not revert from protected mode to the basic 8086-compatible real mode without a hardware-initiated reset, though it worked correctly, the method imposed a huge performance penalty
8.
Intel 8088
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The Intel 8088 microprocessor is a variant of the Intel 8086. Introduced on July 1,1979, the 8088 had an 8-bit external data bus instead of the 16-bit bus of the 8086, the 16-bit registers and the one megabyte address range were unchanged, however. In fact, according to the Intel documentation, the 8086 and 8088 have the execution unit —only the bus interface unit is different. The original IBM PC was based on the 8088, the 8088 was designed in Israel, at Intels Haifa laboratory, as were a large number of Intels processors. The prefetch queue of the 8088 was shortened to four bytes, from the 8086s six bytes, and these modifications of the basic 8086 design were one of the first jobs assigned to Intels then new design office and laboratory in Haifa, Israel. Later followed the 80C88, a fully static CHMOS design, which could operate with clock speeds from 0 to 8 MHz, there were also several other, more or less similar, variants from other manufacturers. For instance, the NEC V20 was a pin compatible and slightly faster variant of the 8088, successive NEC8088 compatible processors would run at up to 16 MHz. In 1984, Commodore International signed a deal to manufacture the 8088 for use in a licensed Dynalogic Hyperion clone, when announced, the list price of the 8088 was US $124.80. The 8088 is architecturally similar to the 8086. The main difference is there are only 8 data lines instead of the 8086s 16 lines. All of the pins of the device perform the same function as they do with the 8086 with two exceptions. First, pin 34 is no longer BHE, instead it outputs a maximum mode status, SSO. Combined with the IO/M and DT/R signals, the bus cycles can be decoded, the second change is the pin that signals if a memory access or input/output access is being made has had it sense reversed. The pin on the 8088 is IO/M, on the 8086 part it is IO/M. The reason for the reversal is that it makes the 8088 compatible with the 8085. 33–1 million instructions per second. The speed of the unit and the bus of the 8086 CPU was well balanced, with a typical instruction mix. Cutting down the bus to 8 bits made it a bottleneck in the 8088. With the speed of instruction fetch reduced by 50% in the 8088 as compared to the 8086, when the queue is empty, instructions take as long to complete as they take to fetch
9.
IBM Personal Computer
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The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12,1981 and it was created by a team of engineers and designers under the direction of Don Estridge of the IBM Entry Systems Division in Boca Raton, Florida. IBM compatible became an important criterion for sales growth, only the Apple Macintosh family kept significant market share without compatibility with the IBM personal computer, International Business Machines, one of the worlds largest companies, had a 62% share of the mainframe computer market in 1981. Its share of the computer market, however, had declined from 60% in 1970 to 32% in 1980. In 1979 BusinessWeek asked, Is IBM just another stodgy, mature company, by 1981 its stock price had declined by 22%. IBMs earnings for the first half the year grew by 5. 3%—one third of the inflation rate—while those of minicomputer maker Digital Equipment Corporation grew by more than 35%. B. M, No longer dominates the computer business. IBM wished to avoid the outcome with the new personal computer industry, dominated by the Commodore PET, Atari 8-bit family, Apple II, Tandy Corporations TRS-80. With $150 million in sales by 1979 and projected growth of more than 40% in the early 1980s. The Japanese project, codenamed Go, ended before the 1981 release of the American-designed IBM PC codenamed Chess, whether IBM had waited too long to enter an industry in which Apple and others were already successful was unclear. An observer stated that IBM bringing out a computer would be like teaching an elephant to tap dance. Successful microcomputer company Vector Graphics fiscal 1980 revenue was $12 million, the company only sold through its internal sales force, had no experience with resellers or retail stores, and did not introduce the first product designed to work with non-IBM equipment until 1980. Another observer claimed that IBM made decisions so slowly that, when tested, as with other large computer companies, its new products typically required about four to five years for development. IBM had to learn how to develop, mass-produce. The potential importance to microcomputers of a company so prestigious, that a saying in American companies stated No one ever got fired for buying IBM, was nonetheless clear. InfoWorld, which described itself as The Newsweekly for Microcomputer Users, stated that for my grandmother, is far and away the media star, not because of its features, but because it exists at all. When the number eight company in the Fortune 500 enters the field, the influence of a personal computer made by a company whose name has literally come to mean computer to most of the world is hard to contemplate. The editorial acknowledged that some factions in our industry have looked upon IBM as the enemy, desktop sized programmable calculators by Hewlett Packard had evolved into the HP9830 BASIC language computer by 1972. In 1972–1973 a team led by Dr. SCAMP emulated an IBM1130 minicomputer 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 HP9800 offered only BASIC
10.
IBM Personal Computer XT
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The IBM Personal Computer XT, often shortened to the IBM XT, PC XT, or simply XT, is a version of the IBM PC with a built-in hard drive. It was released as IBM Machine Type number 5160 on March 8,1983, apart from the hard drive, it was essentially the same as the original PC, with only minor improvements. The XT was mainly intended as an enhanced IBM PC for business users, later floppy-only models would effectively replace the original model 5150 PC. A corresponding 3270 PC featuring 3270 terminal emulation was released later in October 1983, the motherboard had an Intel 8088 microprocessor running at 4.77 MHz, with a socket for an optional 8087 math coprocessor. IBM recognized soon after the IBM PCs release in 1981 that its five 8-bit I/O channel expansion slots were insufficient. An internal IBM publication stated in October 1981 about the number that In my opinion, it could be a problem, a BYTE Magazine article commented that DOS2.0 is more revolutionary and advanced than the computer itself. Unlike many hard disk systems on microcomputers at the time, the XT was able to boot directly off the drive, aside from the hard disk, a serial port card was also standard equipment on the XT, all other cards being optional. By the end of 1983, the XT was neck-and-neck with the original PC for sales, two were behind the floppy drive and shorter than PCs slots. The other six fit into the space as the PCs five slots. Most PC cards would not fit into the two slots, and some would not fit into the six standard-length, but narrower, slots. The floppy and hard drive adapters, the serial port card, the basic specification was soon upgraded to have 256 KB of RAM as standard. Expansion slots could be used for I/O devices or for memory expansion, available Video cards were initially the Monochrome Display Adapter and Color Graphics Adapter, with Enhanced Graphics Adapter and Professional Graphics Controller becoming available in 1984. The XT had a case similar to that of the IBM PC. It weighed 32 pounds and was approximately 19.5 inches wide by 16 inches deep by 5.5 inches high, the power supply of the original XT sold in the US was configured for 120 V AC only and could not be used with 240 V mains supplies. XTs with 240V-compatible power supplies were sold in international markets. Both were rated at 130 Watts, the operating system usually sold with the XT was PC DOS2.0 or, by the time the XT was discontinued in early 1987, DOS3.2. Like the original PC, the XT came with IBM BASIC in its ROM, the XT BIOS also displayed a memory count during the POST, unlike the PC. The XT was discontinued in the spring of 1987, replaced by the PS/2 Model 30, XT motherboards came in two different versions
11.
IBM PC compatible
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IBM PC compatible computers are those similar to the original IBM PC, XT, and AT, able to run the same software and support the same expansion cards as those. Such computers used to be referred to as PC clones, or IBM clones, Columbia Data Products built the first clone of the IBM personal computer by a clean room implementation of its BIOS. Early IBM PC compatibles used the computer bus as the original PC. The IBM AT compatible bus was named the Industry Standard Architecture bus by manufacturers of compatible computers. The term IBM PC compatible is now a historical description only, only the Apple Macintosh classic Mac OS and macOS kept significant market share without compatibility with the IBM personal computer, so consumers are typically identified as being a PC or Mac user. IBM decided in 1980 to market a low-cost single-user computer as quickly as possible in response to Apple Computers success in the microcomputer market. On 12 August 1981, the first IBM PC went on sale, there were three operating systems available for it. The least expensive and most popular was PC DOS made by Microsoft, in a crucial concession, IBMs agreement allowed Microsoft to sell its own version, MS-DOS, for non-IBM computers. The only component of the original PC architecture exclusive to IBM was the BIOS and this software would run on any machine using MS-DOS or PC-DOS. Software that directly addressed the hardware instead of making standard calls was faster, however, software addressing IBM PC hardware in this way would not run on MS-DOS machines with different hardware. The 808x computer marketplace rapidly excluded all machines which were not hardware-, the 640 KB barrier on conventional system memory available to MS-DOS is a legacy of that period, other non-clone machines, while subject to a limit, could exceed 640 kB. Rumors of lookalike, compatible computers, created without IBMs approval, by June 1983 PC Magazine defined PC clone as a computer accommodate the user who takes a disk home from an IBM PC, walks across the room, and plugs it into the foreign machine. Because of a shortage of IBM PCs that year, many customers purchased clones instead, Columbia Data Products produced the first computer more or less compatible to the IBM PC standard during June 1982, soon followed by Eagle Computer. Compaq announced its first IBM PC compatible in November 1982, the Compaq Portable, the Compaq was the first sewing machine-sized portable computer that was essentially 100% PC-compatible. The company could not copy the BIOS directly as a result of the decision in Apple v. Franklin. Each computer would have its own Original Equipment Manufacturer version of MS-DOS, any software written for MS-DOS would operate on any MS-DOS computer, despite variations in hardware design. This expectation seemed reasonable in the marketplace of the time. Until then Microsoft was based primarily on computer languages such as BASIC, the established small system operating software was CP/M from Digital Research which was in use both at the hobbyist level and by the more professional of those using microcomputers
12.
Micro Channel architecture
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Micro Channel architecture, or the Micro Channel bus, was a proprietary 16- or 32-bit parallel computer bus introduced by IBM in 1987 which was used on PS/2 and other computers until the mid-1990s. Its name is abbreviated as MCA, although not by IBM. In IBM products, it superseded the ISA bus and was subsequently superseded by the PCI bus architecture. The development of Micro Channel was driven by both technical and business pressures, the IBM AT bus, which later became known as the Industry Standard Architecture bus had a number of technical design limitations, including, A slow bus speed. A limited number of interrupts, fixed in hardware, a limited number of I/O device addresses, also fixed in hardware. Hardwired and complex configuration with no conflict resolution, deep links to the architecture of the 80x86 chip family In addition, it suffered from other problems, Poor grounding and power distribution. Undocumented bus interface standards that varied between systems and manufacturers and these limitations became more serious as the range of tasks and peripherals, and the number of manufacturers for IBM PC-compatibles, grew. It was thought that by creating a new standard, IBM would regain control of standards via the required licensing, as patents can take three years or more to be granted, however, only those relating to ISA could be licensed when Micro Channel was announced. Patents on important Micro Channel features, such as Plug and Play automatic configuration, were not granted to IBM until after PCI had replaced Micro Channel in the marketplace, the Micro Channel architecture was designed by engineer Chet Heath. A lot of the Micro Channel cards that were developed used the CHIPS P82C612 MCA interface controller, the Micro Channel was primarily a 32-bit bus, but the system also supported a 16-bit mode designed to lower the cost of connectors and logic in Intel-based machines like the IBM PS/2. In time, memory moved to the CPUs local bus, thereby eliminating the problem, another connector extension was included for graphics cards. This extension was used for analog output from the video card, the advantage of this was that Micro Channel system boards could have a basic VGA or MCGA graphics system on board, and higher level graphics could then share the same port. Micro Channel cards also featured a unique, 16-bit software-readable ID, the BIOS and/or OS can read IDs, compare against a list of known cards, and perform automatic system configuration to suit. This led to boot failures whereby an older BIOS would not recognize a newer card, in turn, this required IBM to release updated Reference Disks on a regular basis. A fairly complete list of known IDs is available, to accompany these reference disks were ADF files which were read by setup which in turn provided configuration information for the card. The ADF was a text file, containing information about the cards memory addressing. In this critical area, Micro Channel architectures biggest advantage was also its greatest disadvantage, in practice, however, this meant that the user must keep that same floppy disk matched to that PC. For a small company with a few PCs, this was annoying, but for large organizations with hundreds or even thousands of PCs, permanently matching each PC with its own floppy disk was logistically unlikely or impossible
13.
Extended Industry Standard Architecture
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The Extended Industry Standard Architecture is a bus standard for IBM PC compatible computers. It was announced in September 1988 by a consortium of PC clone vendors as a counter to IBMs use of its proprietary Micro Channel architecture in its PS/2 series, the bus mastering support is also enhanced to provide access to 4 GB of memory. Unlike MCA, EISA can accept older XT and ISA boards — the lines, EISA was much favoured by manufacturers due to the proprietary nature of MCA, and even IBM produced some machines supporting it. It was somewhat expensive to implement, so it never became popular in desktop PCs. However, it was successful in the server market, as it was better suited to bandwidth-intensive tasks. Most EISA cards produced were either SCSI or network cards, EISA was also available on some non-IBM compatible machines such as the AlphaServer, HP 9000-D, SGI Indigo2 and MIPS Magnum. By the time there was a market need for a bus of these speeds and capabilities for desktop computers. The original IBM PC included five 8-bit slots, running at the clock speed of 4.77 MHz. The PC/AT, introduced in 1984, had three 8-bit slots and five 16-bit slots, all running at the clock speed of 6 MHz in the earlier models and 8 MHz in the last version of the computer. The 16-bit slots were a superset of the 8-bit configuration, so most 8-bit cards were able to plug into a 16-bit slot, one of the key reasons for the success of the IBM PC was the active ecosystem of third-party expansion cards available for the machines. IBM was restricted from patenting the bus, and widely published the bus specifications, as the PC-clone industry continued to build momentum in the mid- to late-1980s, several problems with the bus began to be apparent. First, because the AT slot was not managed by any central standards group, one of the most common issues was that as PC clones became more common, PC manufacturers began ratcheting up the processor speed to maintain a competitive advantage. Unfortunately, because the ISA bus was originally locked to the processor clock, in fact, the first system to clock the ISA bus at 8 MHz was the turbo 8088 clones that clocked the processors at 8 MHz. This caused many issues with incompatibility, where a true IBM-compatible third-party card might not work in a higher speed system, most PC makers eventually decoupled the slot clock from the system clock, but there was still no standards body to police the industry. Because of this, when the first 386-based system hit the market in 1986, other 386 PCs followed suit, and the AT bus remained a part of most systems even into the late 1990s. Meanwhile, IBM began to worry that it was losing control of the industry it had created, in 1987, IBM released the PS/2 line of computers, which included the MCA bus. MCA included numerous enhancements over the 16-bit AT bus, including bus mastering, burst mode, software configurable resources, however, in an effort to reassert its dominant role, IBM patented the bus, and placed stringent licensing and royalty policies on its use. A few manufacturers did produce licensed MCA machines, but overall the industry balked at IBMs restrictions, steve Gibson proposed that clone makers adopt NuBus
14.
VESA Local Bus
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The VESA Local Bus is a short-lived expansion bus that was mostly used in personal computers. VESA Local Bus worked alongside the ISA bus, acting as a conduit for memory-mapped I/O and DMA, while the ISA bus handled interrupts. In the early 1990s, the I/O bandwidth of the ISA bus was becoming a bottleneck to PC graphics performance. The need for faster graphics was being driven by increasing adoption of graphical user interfaces in PC operating systems, the competing EISA open standard was still unable to offer enough performance improvement over ISA to provide a solution. However, as these manufacturer-specific solutions were not standardized, there were no provisions for providing interoperability between them and this led to the VESA consortium proposing and defining a Local Bus standard in 1992. A VLB slot itself was simply an additional edge connector placed in-line with the traditional ISA or EISA connector, the result was a normal ISA or EISA slot being additionally capable of accepting VLB-compatible cards. Traditional ISA cards remained compatible as they would not have pins past the normal ISA or EISA portion of the slot. The reverse was also true – VLB cards were by necessity quite long in order to reach the VLB connector, and were reminiscent of older full-length expansion cards from the earlier IBM XT era. Ironically, the VLB portion of a slot looked similar to an IBM MCA slot, as indeed it was the same physical 116-pin connector used by MCA cards, rotated by 180 degrees. The IBM MCA standard had not been as popular as IBM expected and there was a surplus of the connector, making it inexpensive. The VESA Local Bus was designed as a solution to the problem of the ISA buss limited bandwidth. As VLB fundamentally tied a card directly to the 486 processor bus with minimal intermediary logic, timing and arbitration duties were strongly dependent on the cards and CPU. When the Pentium processor arrived there were differences in its bus design. Few Pentium motherboards with VLB slots were ever made, and used VLB-to-PCI bridges such as the OPTi 82C822, also moving the bus to non-x86 architectures was nearly impossible. Limited number of slots available Most PCs that used VESA Local Bus had only one or two VLB capable ISA slots from the five or six available, thus, four ISA slots generally were just that, ISA only. This was a result of VESA Local Bus being a branch of the 80486 memory bus. The processor did not have the ability to correctly drive more than two or three devices at a time directly from this bus. Reliability problems The strict electrical limitations on the bus also reduced any safety margin available, glitches between cards were common, as the interaction between individual cards, combinations of cards, motherboard implementation, and even the processor itself was difficult to predict
15.
Industry Standard Architecture
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Industry Standard Architecture is a retronym term for the 16-bit internal bus of IBM PC/AT and similar computers based on the Intel 80286 and its immediate successors during the 1980s. The bus was backward compatible with the 8-bit bus of the 8088-based IBM PC, originally referred to as the PC/AT-bus it was also termed I/O Channel by IBM. The 16-bit ISA bus was used with 32-bit processors for several years. An attempt to extend it to 32 bits, called Extended Industry Standard Architecture, was not very successful, later buses such as VESA Local Bus and PCI were used instead, often along with ISA slots on the same mainboard. Derivatives of the AT bus structure were and still are used in ATA/IDE, the PCMCIA standard, Compact Flash, the PC/104 bus, compaq created the term Industry Standard Architecture to replace PC compatible. The ISA bus was developed by a led by Mark Dean at IBM as part of the IBM PC project in 1981. It originated as an 8-bit system, the newer 16-bit standard, the IBM AT bus, was introduced in 1984. Therefore, the ISA bus was synchronous with the CPU clock, designed to connect peripheral cards to the motherboard, ISA allows for bus mastering although only the first 16 MB of main memory are available for direct access. The 8-bit bus ran at 4.77 MHz, while the 16-bit bus operated at 6 or 8 MHz IBM RT/PC also used the 16-bit bus. It was also available on some non-IBM compatible machines such as Motorola 68k-based Apollo and Amiga 3000 workstations, the short-lived AT&T Hobbit and later PowerPC based BeBox. MCA had many features that would appear in PCI, the successor of ISA. The system was far more advanced than the AT bus, and computer manufacturers responded with the Extended Industry Standard Architecture and later, in fact, VLB used some electronic parts originally intended for MCA because component manufacturers already were equipped to manufacture them. Both EISA and VLB were backwards-compatible expansions of the AT bus, users of ISA-based machines had to know special information about the hardware they were adding to the system. While a handful of devices were essentially plug-n-play, this was rare, users frequently had to configure several parameters when adding a new device, such as the IRQ line, I/O address, or DMA channel. MCA had done away with this complication, and PCI actually incorporated many of the ideas first explored with MCA, in reality, ISA PnP can be troublesome, and did not become well-supported until the architecture was in its final days. PCI slots were the first physically incompatible expansion ports to directly squeeze ISA off the motherboard, at first, motherboards were largely ISA, including a few PCI slots. By the mid-1990s, the two types were roughly balanced, and ISA slots soon were in the minority of consumer systems. Which was why the software compatible LPC bus was created, in late 2008, even floppy disk drives and serial ports were disappearing, and the extinction of vestigial ISA from chipsets was on the horizon
16.
Parallel ATA
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Parallel ATA, originally AT Attachment, is an interface standard for the connection of storage devices such as hard disk drives, floppy disk drives, and optical disc drives in computers. The standard is maintained by the X3/INCITS committee and it uses the underlying AT Attachment and AT Attachment Packet Interface standards. The Parallel ATA standard is the result of a history of incremental technical development. The ATA interface itself evolved in stages from Western Digitals original Integrated Drive Electronics interface. As a result, many near-synonyms for ATA/ATAPI and its previous incarnations are still in informal use, in particular Extended IDE. After the introduction of Serial ATA in 2003, the original ATA was renamed to Parallel ATA, Parallel ATA cables have a maximum allowable length of only 18 in. Because of this limit, the technology normally appears as a computer storage interface. For many years, ATA provided the most common and the least expensive interface for this application and it has largely been replaced by SATA in newer systems. The PATA standard was originally conceived as the PC/AT Attachment because its primary feature was a connection to the 16-bit ISA bus introduced with the IBM PC/AT. The AT in IBM PC/AT refers to Advanced Technology, but the ATA specifications simply use the name AT Attachment, the first version of what is now called the ATA/ATAPI interface was developed by Western Digital under the name Integrated Drive Electronics. The first such drives appeared in Compaq PCs in 1986, the interface cards used to connect a parallel ATA drive to, for example, a PCI slot are not drive controllers, they are merely bridges between the host bus and the ATA interface. Since the original ATA interface is essentially just a 16-bit ISA bus in disguise, the integrated controller presented the drive to the host computer as an array of 512-byte blocks with a relatively simple command interface. All of these details of the mechanical operation of the drive were now handled by the controller on the drive itself. This also eliminated the need to design a controller that could handle many different types of drives. The host need only ask for a sector, or block, to be read or written. The interface used by these drives was standardized in 1994 as ANSI standard X3. 221-1994, after later versions of the standard were developed, this became known as ATA-1. A short-lived, seldom-used implementation of ATA was created for the IBM XT and it has been referred to as XT-IDE, XTA or XT Attachment. At the time, in combination with the drive, this was sufficient for most people
17.
CompactFlash
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CompactFlash is a flash memory mass storage device used mainly in portable electronic devices. The format was specified and the devices were first manufactured by SanDisk in 1994, CompactFlash became the most successful of the early memory card formats, surpassing Miniature Card and SmartMedia. Subsequent formats, such as MMC/SD, various Memory Stick formats, most of these cards are smaller than CompactFlash while offering comparable capacity and speed. Proprietary memory card formats for use in audio and video, such as P2 and SxS, are faster. CompactFlash remains popular and is supported by many devices and high-end consumer devices. As of 2017, both Canon and Nikon use CompactFlash for their digital still cameras. Canon also chose CompactFlash as the medium for its professional high-definition tapeless video cameras. Ikegami professional video cameras can record video onto CompactFlash cards through an adaptor. Traditional CompactFlash cards use the Parallel ATA interface, but in 2008, CFast is based on the Serial ATA interface. In November 2010, SanDisk, Sony and Nikon presented a next generation card format to the CompactFlash Association, the new format has a similar form factor to CF/CFast but is based on the PCI Express interface instead of Parallel ATA or Serial ATA. The XQD card format was announced by the CompactFlash Association in December 2011. There are two subdivisions of CF cards,3.3 mm-thick type I and 5 mm-thick type II. The type II slot is used by miniature hard drives and some other devices, there are four main card speeds, original CF, CF High Speed, faster CF3.0 standard and the faster CF4.0 standard adopted as of 2007. CompactFlash was originally built around Intels NOR-based flash memory, but has switched to NAND technology, CF is among the oldest and most successful formats, and has held a niche in the professional camera market especially well. It has benefited from both a better cost to memory-size ratio and, for much of the life, generally greater available capacity than other formats. As some newer types are smaller, they can be used directly in a CF card slot with an adapter. Formats that can be used this way include SD/MMC, Memory Stick Duo, xD-Picture Card in a Type I slot and SmartMedia in a Type II slot, some multi-card readers use CF for I/O as well. The CompactFlash interface is a 50-pin subset of the 68-pin PCMCIA connector and it can be easily slipped into a passive 68-pin PCMCIA Type II to CF Type I adapter that fully meets PCMCIA electrical and mechanical interface specifications, according to compactflash. org
18.
PC/104
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PC/104 is a family of embedded computer standards which define both form factors and computer buses. PC/104 is intended for specialized environments where a small, rugged computer system is required, the standard is modular, and allows consumers to stack together boards from a variety of COTS manufacturers to produce a customized embedded system. The original PC/104 form factor is somewhat smaller than a desktop PC motherboard at 3.550 ×3.775 inches. Unlike other popular computer form factors such as ATX, which rely on a motherboard or backplane, the PC/104 specification defines four mounting holes at the corners of each module, which allow the boards to be fastened to each other using standoffs. The stackable bus connectors and use of standoffs provides a more rugged mounting than slot boards found in desktop PCs, the compact board size further contributes to the ruggedness of the form factor by reducing the possibility of PCB flexing under shock and vibration. A typical PC/104 system will include a CPU board, power supply board, a wide array of peripheral boards are available from various vendors. Users may design a stack that incorporates boards from multiple vendors, the overall height, weight, and power consumption of the stack can vary depending on the number of boards that are used. PC/104 is sometimes referred to as a stackable PC, as most of the architecture derives from the desktop PC, the majority of PC/104 CPU boards are x86 compatible and include standard PC interfaces such as Serial Ports, USB, Ethernet, and VGA. A x86 PC/104 system is capable of standard PC operating system such as DOS, Windows. However, it is quite common to use a real-time operating system. The PC/104 bus and form factor was originally devised by Ampro in 1987, an IEEE standard corresponding to PC/104 was drafted as IEEE P996.1, but never ratified. In 1997, the PC/104 Consortium introduced a standard based on the PCI bus. A PCI Express-based standard was introduced in 2008, pC/104-related specifications are controlled by the PC/104 Consortium. There are currently 47 members of the Consortium, all specifications published by the Consortium are freely available. Membership in the Consortium is not required to design and manufacture a PC/104 board, the specifications released by the PC/104 Consortium define multiple of Bus Structures and Form Factors. Bus Structure defines the location and pinout of the bus connector, Form Factor refers to size and shape of the board. It is possible to one of the PC/104 stackable expansion buses on a number of different form factors. Note the term PC/104 is often used interchangeably to refer to either the Bus Structure or Form Factor and this can be a source of confusion
19.
Super I/O
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Super I/O is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a variety of low-bandwidth devices, the original super I/O chips communicated with the central processing unit via the Industry Standard Architecture bus. Modern super I/O chips use the Low Pin Count bus instead of ISA for communication with the Central processing unit and this normally occurs through an LPC interface on the southbridge chip of the motherboard. Companies that make super I/O controllers include Nuvoton, ITE, Fintek, national Semiconductor used to make super I/O controllers but sold that business to Winbond, which already had a competing super I/O controller business. Winbond then spun off its logic businesses to a wholly owned subsidiary, SMSC made Super I/O chips and then got acquired by Microchip Technology. Archived from the original on 2008-05-18, superiotool is a Linux user-space tool to detect which Super I/O is used on a mainboard, and it can provide detailed information about its register contents. Lm-sensors contains a tool named sensors-detect that can detect which Super I/O is used on a mainboard
20.
Compaq
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Compaq was a company founded in 1982 that developed, sold, and supported computers and related products and services. Compaq produced some of the first IBM PC compatible computers, being the first company to reverse engineer the IBM Personal Computer. It rose to become the largest supplier of PC systems during the 1990s before being overtaken by HP in 2001, struggling in the aftermath of the dot-com bubble bust, as well as with a risky acquisition of DEC, Compaq was acquired for US$25 billion by HP in 2002. The Compaq brand remained in use by HP for lower-end systems until 2013 when it was discontinued, the company was formed by Rod Canion, Jim Harris and Bill Murto—former Texas Instruments senior managers. Murto departed Compaq in 1987, while Canion and Harris left under a shakeup in 1991, prior to its takeover the company was headquartered in a facility in northwest unincorporated Harris County, Texas, that now continues as HPs largest United States facility. Compaq was founded in February 1982 by Rod Canion, Jim Harris and Bill Murto, the three of them had left due to lack of faith and loss of confidence in TIs management, and initially considered but ultimately decided against starting a chain of Mexican restaurants. Each invested $1,000 to form the company, which was founded with the temporary name Gateway Technology, the name COMPAQ was said to be derived from Compatibility and Quality but this explanation was an afterthought. The name was chosen from many suggested by Ogilvy and Mather, the first Compaq PC was sketched out on a placemat by Canion while dining with the founders in a Houston pie shop. Their first venture came from Benjamin M. Rosen and Sevin Rosen Funds who helped the fledgling company secure $1.5 million to produce their initial computer. Overall, the managed to raise $25 million from venture capitalists. In contrast to Dell Computer and Gateway 2000, Compaq hired veteran engineers with an average of 15 years experience, under Canions direction, Compaq sold computers only through dealers to avoid potential competition that a direct sales channel would foster, which helped foster loyalty among resellers. By giving dealers considerable leeway in pricing Compaqs offerings, either a significant markup for more profits or discount for more sales, dealers had a major incentive to advertise Compaq. During its first year of sales, the company sold 53,000 PCs for sales of $111 million, Compaq went public in 1983 on the NYSE and raised $67 million. In 1986, it enjoyed record sales of $329 million from 150,000 PCs, in 1987, Compaq hit the $1 billion revenue mark, taking the least amount of time to reach that milestone. By 1991, Compaq held the fifth spot in the PC market with $3 billion in sales that year. Two key marketing executives in Compaqs early years, Jim DArezzo, other key executives responsible for the companys meteoric growth in the late 80s and early 90s were Ross A. In the United States, Brendan A. Mac McLoughlin led the companys sales organization after starting up the Western U. S. The soft-spoken Canion was popular with employees and the culture that he built helped Compaq to attract the best talent, at semi-annual meetings, turnout was high as any employee could ask questions to senior managers
21.
PC compatible
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IBM PC compatible computers are those similar to the original IBM PC, XT, and AT, able to run the same software and support the same expansion cards as those. Such computers used to be referred to as PC clones, or IBM clones, Columbia Data Products built the first clone of the IBM personal computer by a clean room implementation of its BIOS. Early IBM PC compatibles used the computer bus as the original PC. The IBM AT compatible bus was named the Industry Standard Architecture bus by manufacturers of compatible computers. The term IBM PC compatible is now a historical description only, only the Apple Macintosh classic Mac OS and macOS kept significant market share without compatibility with the IBM personal computer, so consumers are typically identified as being a PC or Mac user. IBM decided in 1980 to market a low-cost single-user computer as quickly as possible in response to Apple Computers success in the microcomputer market. On 12 August 1981, the first IBM PC went on sale, there were three operating systems available for it. The least expensive and most popular was PC DOS made by Microsoft, in a crucial concession, IBMs agreement allowed Microsoft to sell its own version, MS-DOS, for non-IBM computers. The only component of the original PC architecture exclusive to IBM was the BIOS and this software would run on any machine using MS-DOS or PC-DOS. Software that directly addressed the hardware instead of making standard calls was faster, however, software addressing IBM PC hardware in this way would not run on MS-DOS machines with different hardware. The 808x computer marketplace rapidly excluded all machines which were not hardware-, the 640 KB barrier on conventional system memory available to MS-DOS is a legacy of that period, other non-clone machines, while subject to a limit, could exceed 640 kB. Rumors of lookalike, compatible computers, created without IBMs approval, by June 1983 PC Magazine defined PC clone as a computer accommodate the user who takes a disk home from an IBM PC, walks across the room, and plugs it into the foreign machine. Because of a shortage of IBM PCs that year, many customers purchased clones instead, Columbia Data Products produced the first computer more or less compatible to the IBM PC standard during June 1982, soon followed by Eagle Computer. Compaq announced its first IBM PC compatible in November 1982, the Compaq Portable, the Compaq was the first sewing machine-sized portable computer that was essentially 100% PC-compatible. The company could not copy the BIOS directly as a result of the decision in Apple v. Franklin. Each computer would have its own Original Equipment Manufacturer version of MS-DOS, any software written for MS-DOS would operate on any MS-DOS computer, despite variations in hardware design. This expectation seemed reasonable in the marketplace of the time. Until then Microsoft was based primarily on computer languages such as BASIC, the established small system operating software was CP/M from Digital Research which was in use both at the hobbyist level and by the more professional of those using microcomputers
22.
Megabyte
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The megabyte is a multiple of the unit byte for digital information. Its recommended unit symbol is MB, but sometimes MByte is used, the unit prefix mega is a multiplier of 1000000 in the International System of Units. Therefore, one megabyte is one million bytes of information and this definition has been incorporated into the International System of Quantities. However, in the computer and information fields, several other definitions are used that arose for historical reasons of convenience. A common usage has been to one megabyte as 1048576bytes. However, most standards bodies have deprecated this usage in favor of a set of binary prefixes, less common is a convention that used the megabyte to mean 1000×1024 bytes. The megabyte is commonly used to measure either 10002 bytes or 10242 bytes, the interpretation of using base 1024 originated as a compromise technical jargon for the byte multiples that needed to be expressed by the powers of 2 but lacked a convenient name. As 1024 approximates 1000, roughly corresponding to the SI prefix kilo-, in 1998 the International Electrotechnical Commission proposed standards for binary prefixes requiring the use of megabyte to strictly denote 10002 bytes and mebibyte to denote 10242 bytes. By the end of 2009, the IEC Standard had been adopted by the IEEE, EU, ISO, the Mac OS X10.6 file manager is a notable example of this usage in software. Since Snow Leopard, file sizes are reported in decimal units, base 21 MB =1048576 bytes is the definition used by Microsoft Windows in reference to computer memory, such as RAM. This definition is synonymous with the binary prefix mebibyte. Mixed 1 MB =1024000 bytes is the used to describe the formatted capacity of the 1.44 MB3. 5inch HD floppy disk. Semiconductor memory doubles in size for each address lane added to an integrated circuit package, the capacity of a disk drive is the product of the sector size, number of sectors per track, number of tracks per side, and the number of disk platters in the drive. Changes in any of these factors would not usually double the size, sector sizes were set as powers of two for convenience in processing. It was an extension to give the capacity of a disk drive in multiples of the sector size, giving a mix of decimal. Depending on compression methods and file format, a megabyte of data can roughly be, a 4 megapixel JPEG image with normal compression. Approximately 1 minute of 128 kbit/s MP3 compressed music,6 seconds of uncompressed CD audio. A typical English book volume in plain text format, the human genome consists of DNA representing 800 MB of data
23.
Motorola 68000 series
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The Motorola 68000 series is a family of 32-bit complex instruction set computer microprocessors. During the 1980s and early 1990s, they were popular in personal computers and they were most well known as the processors powering the early Apple Macintosh, the Commodore Amiga, the Sinclair QL, the Atari ST, the WeatherStar, the Sega Genesis, and several others. However, they became most well known as the processors powering desktop computers such as the Apple Macintosh, the Commodore Amiga, the Sinclair QL, the Atari ST, and several others. The 68000 was also the processor of choice in the 1980s for Unix workstations and servers from firms such as Sun Microsystems, NeXT and Silicon Graphics. There was a 68000 version of CP/M called CP/M-68K, which was proposed to be the Atari ST operating system. Also, and perhaps most significantly, the first several versions of Adobes PostScript interpreters were 68000-based, the 68000 in the Apple LaserWriter and LaserWriter Plus was clocked faster than the version used then in Macintosh computers. Thereafter, Adobe generally preferred a RISC for its processor, as its competitors, with their PostScript clones, had gone with RISCs. The early 68000-based Adobe PostScript interpreters and their hardware were named for cold war U. S. rockets and missiles, Atlas, Redstone, today, these systems are either end-of-line, or are using different processors. Since these platforms had their peak in the 1980s, their original manufacturers are unlikely to support an operating system for this hardware or are even out of business. However, the GNU/Linux, NetBSD and OpenBSD operating systems include support for 68000 processors. The 68000 processors were used in the Sega Genesis and SNK Neo Geo consoles as the main CPU. Many arcade boards also used 68000 processors including boards from Capcom, SNK, microcontrollers derived from the 68000 family have been used in a huge variety of applications. For example, CPU32 and ColdFire microcontrollers have been manufactured in the millions as automotive engine controllers, people who are familiar with the PDP-11 or VAX usually feel comfortable with the 68000. With the exception of the split of general purpose registers into specialized data and address registers and it had a more orthogonal instruction set than those of many processors that came before and after. That is, it was possible to combine operations freely with operands. This property made programming relatively easy for humans, and also made it easier to write code generators for compilers, there was no 68050, though at one point it was a project within Motorola. Many of these optimizations were included with the 68060 and were part of its design goals. There is also no revision of the 68060, as Motorola was in the process of shifting away from the 68000 and 88k processor lines into its new PowerPC business, had it been, it would have been a revised 68060, likely with a superior FPU
24.
Apollo Computer
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Apollo Computer Inc. founded 1980 in Chelmsford, Massachusetts by William Poduska and others, developed and produced Apollo/Domain workstations in the 1980s. Along with Symbolics and Sun Microsystems, Apollo was one of the first vendors of graphical workstations in the 1980s, like computer companies at the time and unlike manufacturers of IBM PC compatibles, Apollo produced much of its own hardware and software. Apollo was acquired by Hewlett-Packard in 1989 for US$476 million, Apollo was started in 1980, two years before Sun Microsystems. Besides Poduska, the founders included Dave Nelson, Mike Greata, Charlie Spector, Bob Antonuccio, Gerry Stanley, the founding engineering team included Mike Sporer, Bernie Stumpf, Russ Barbour, Paul Leach, and Andy Marcuvitz. In 1981, the company unveiled the DN100 workstation, which used the Motorola 68000 microprocessor, Apollo workstations ran Aegis, a proprietary operating system with a POSIX-compliant Unix alternative frontend. Apollos networking was particularly elegant, among the first to allow demand paging over the network, from 1980 to 1987, Apollo was the largest manufacturer of network workstations. At the end of 1987, it was third in market share after Digital Equipment Corporation and Sun, apollos largest customers were Mentor Graphics, General Motors, Ford, Chrysler, Chicago Research and Trading and Boeing. Apollo was acquired by Hewlett-Packard in 1989 for US $476 million, but after acquiring Apollo Computer in 1989, HP integrated a lot of Apollo technology into their own HP9000 series of workstations and servers. The Apollo engineering center took over PA-RISC workstation development and Apollo became an HP workstation brand name for a while, Apollo also invented the revision control system DSEE which inspired IBM Rational ClearCase. Apollo machines used an operating system, Aegis, because of the excessive cost of single CPU Unix licenses at the time of system definition. Aegis, like Unix, was based on concepts from the Multics time sharing operating system and it used the concepts of shell programming, single level store, and object-oriented design. Aegis was written in a version of Pascal. The dual 68000 processor design was to provide automatic page fault switching, with one acting as a watchdog, while the other executed the OS. When a page fault was raised, the main CPU was halted in mid cycle while the watchdog CPU would bring the page into memory and then allow the main CPU to continue, later improvements in the Motorola 68010 processor obviated the need for the dual processor design. Certain efficiencies were gained by careful design, for example, the page size, network packet. The name space of the network was self discovering as new nodes were added, Domain/OS was initially a layer over Aegis and was not built on a Unix kernel. Release 10 incorporated large parts of Unix but the burden of backwards compatibility with previous releases led to a system that was larger, in the end, Hewlett Packard shut down the Domain/OS line. Release 10 came out as competitors were gaining ground in the area of graphics and windowing systems, particularly with the trend to open systems and the X Window System
25.
Amiga 3000
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The Commodore Amiga 3000, or A3000, is the third major release in the Amiga computer family. Released in June 1990, it features improved processing speed, improved rendering of graphics, and it is the successor to the Amiga 2000. The A3000 however, was reworked and rethought as a high-end workstation. The new 32-bit Zorro III expansion slots provide for faster and more powerful expansion capabilities, in common with earlier Amigas the 3000 runs a 32-bit operating system called AmigaOS. Version 2.0 is generally considered to have an ergonomic and attractive interface than previous versions. Access for application developers was simplified, the A3000UX is an A3000 variant bundled with the UNIX System V operating system. Commodore had an agreement with AT&T to include a port of Unix System V. Commodore also sold a variant called the A3000T. An enhanced version, the Amiga 3000+, with the AGA chipset, instead of the Amiga 3000+, Commodore replaced the A3000 six months behind schedule, in the fall of 1992, with the A4000. The Amiga 3000 shipped with a Motorola 68030 at either 16 or 25 MHz and 2 MB of RAM and it includes the Enhanced Chip Set, a display enhancer for use with a VGA monitor, and a DMA SCSI-II controller and hard disk drive. Fast RAM can be increased by fitting DIP or ZIP DRAM chips available in two varieties, Page Mode or Static Column, the A3000, unlike most Amiga models, supports both ROM-based Kickstarts and disk-based Kickstarts, although not simultaneously. Kickstart V1.4 is actually a version of Kickstart which is loaded from disk. 68040 microprocessors require at least 2.0 ROMs, the A3000 has a number of Amiga-specific connectors including two DE-9 ports for joysticks, mice, and light pens, a standard 25-pin RS-232 serial port and a 25-pin Centronics parallel port. As a result, at launch the A3000 was compatible with many existing Amiga peripherals, such as MIDI devices, serial modems, the A3000 has four internal 32-bit Zorro III expansion slots. This expansion bus allows the use of devices which comply with the AutoConfig standard, such as cards, audio cards, network cards. The two passive ISA slots can be activated by use of a bridgeboard, which connects the Zorro, such bridgeboards typically feature on-board IBM-PC-compatible hardware, including Intel 80286,80386 or 80486 microprocessors allowing emulation of an entire IBM-PC system in hardware. A compatible ISA card may then be installed in the remaining ISA slot
26.
PowerPC
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PowerPC is a RISC instruction set architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM. PowerPC was the cornerstone of AIMs PReP and Common Hardware Reference Platform initiatives in the 1990s and it has since become niche in personal computers, but remain popular as embedded and high-performance processors. Its use in game consoles and embedded applications provided an array of uses. In addition, PowerPC CPUs are still used in AmigaOne and third party AmigaOS4 personal computers, the history of RISC began with IBMs 801 research project, on which John Cocke was the lead developer, where he developed the concepts of RISC in 1975–78. 801-based microprocessors were used in a number of IBM embedded products, the RT was a rapid design implementing the RISC architecture. The result was the POWER instruction set architecture, introduced with the RISC System/6000 in early 1990, the original POWER microprocessor, one of the first superscalar RISC implementations, was a high performance, multi-chip design. IBM soon realized that a microprocessor was needed in order to scale its RS/6000 line from lower-end to high-end machines. Work on a one-chip POWER microprocessor, designated the RSC began, in early 1991, IBM realized its design could potentially become a high-volume microprocessor used across the industry. IBM approached Apple with the goal of collaborating on the development of a family of single-chip microprocessors based on the POWER architecture and this three-way collaboration became known as AIM alliance, for Apple, IBM, Motorola. In 1991, the PowerPC was just one facet of an alliance among these three companies. The PowerPC chip was one of joint ventures involving the three, in their efforts to counter the growing Microsoft-Intel dominance of personal computing. For Motorola, POWER looked like an unbelievable deal and it allowed them to sell a widely tested and powerful RISC CPU for little design cash on their own part. It also maintained ties with an important customer, Apple, and seemed to offer the possibility of adding IBM too, at this point Motorola already had its own RISC design in the form of the 88000 which was doing poorly in the market. Motorola was doing well with their 68000 family and the majority of the funding was focused on this, the 88000 effort was somewhat starved for resources. However, the 88000 was already in production, Data General was shipping 88000 machines, the 88000 had also achieved a number of embedded design wins in telecom applications. The result of various requirements was the PowerPC specification. The differences between the earlier POWER instruction set and PowerPC is outlined in Appendix E of the manual for PowerPC ISA v.2.02, when the first PowerPC products reached the market, they were met with enthusiasm. In addition to Apple, both IBM and the Motorola Computer Group offered systems built around the processors, Microsoft released Windows NT3.51 for the architecture, which was used in Motorolas PowerPC servers, and Sun Microsystems offered a version of its Solaris OS
27.
BeBox
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The BeBox is a dual CPU personal computer, briefly sold by Be Inc. to run the companys own operating system, BeOS. Notable aspects of the system include its CPU configuration, I/O board with GeekPort, the BeBox made its debut in October 1995. The processors were upgraded to 133 MHz in August 1996, production was halted in January 1997, following the port of BeOS to the Macintosh, in order for the company to concentrate on software. Be sold around 100066 MHz BeBoxes and 800133 MHz BeBoxes, initial prototypes are equipped with two AT&T Hobbit processors and three AT&T 9308S DSPs. Production models use two PowerPC603 processors running at 66 or 133 MHz to power the BeBox, digital and analog I/O and DC power connector, 37-pin connector on the ISA bus. Two yellow/green vertical LED arrays, dubbed the blinkenlights, are built into the front bezel to illustrate the CPU load, the bottommost LED on the right side indicates hard disk activity. Multi Emulator Super System - able to emulate both BeBox 66 and 133 The BeBox Zone, archived from the original on 15 April 2013. BeBox Photo Gallery Pinout for the GeekPort connector U. S
28.
Token ring
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Token ring local area network technology is a communications protocol for local area networks. It uses a special three-byte frame called a token that travels around a ring of workstations or servers. This token passing is an access method providing fair access for all stations. Proteon later evolved a 16 Mbit/s version that ran on unshielded twisted pair cable, IBM launched their own proprietary token ring product on October 15,1985. It ran at 4 Mbit/s, and attachment was possible from IBM PCs, midrange computers and it used a convenient star-wired physical topology, and ran over shielded twisted-pair cabling, and shortly thereafter became the basis for the /IEEE standard 802.5. During this time, IBM argued strongly that token ring LANs were superior to Ethernet, especially under load, but these claims were fiercely debated. In 1988 the faster 16 Mbit/s token ring was standardized by the 802.5 working group, Token ring does not inherently support this feature and requires additional software and hardware to operate on a direct cable connection setup. Token ring eliminates collision by the use of a single-use token, Token ring network interface cards contain all of the intelligence required for speed autodetection, routing and can drive themselves on many Multistation Access Units that operate without power. Ethernet network interface cards can operate on a passive hub to a degree, but not as a large LAN. Token ring employs access priority in which certain nodes can have priority over the token, unswitched Ethernet does not have provisioning for an access priority system as all nodes have equal contest for traffic. Multiple identical MAC addresses are supported on token ring, switched Ethernet cannot support duplicate MAC addresses without reprimand. Token Ring was more complex than Ethernet, requiring a specialized processor, by contrast, Ethernet included both the firmware and the lower licensing cost in the MAC chip. The cost of a token ring interface using the Texas Instruments TMS380C16 MAC, even more significant when comparing overall system costs was the much-higher cost of router ports and network cards for token-ring vs Ethernet. The emergence of Ethernet switches may have been the final straw, similar token passing mechanisms are used by ARCNET, token bus, 100VG-AnyLAN and FDDI, and they have theoretical advantages over the CSMA/CD of early Ethernet. A token ring network can be modeled as a system where a single server provides service to queues in a cyclic order. The data transmission process goes as follows, Empty information frames are continuously circulated on the ring, when a computer has a message to send, it seizes the token. The computer will then be able to send the frame, the frame is then examined by each successive workstation. The workstation that identifies itself to be the destination for the copies it from the frame
29.
Network interface controller
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A network interface controller is a computer hardware component that connects a computer to a computer network. Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus, the low cost and ubiquity of the Ethernet standard means that most newer computers have a network interface built into the motherboard. The network controller implements the electronic circuitry required to communicate using a physical layer and data link layer standard such as Ethernet, Fibre Channel. The NIC allows computers to communicate over a network, either by using cables or wirelessly. Although other network technologies exist, IEEE802 networks including the Ethernet variants have achieved near-ubiquity since the mid-1990s, newer server motherboards may even have dual network interfaces built-in. The Ethernet capabilities are integrated into the motherboard chipset or implemented via a low-cost dedicated Ethernet chip. A separate network card is not required unless additional interfaces are needed or some type of network is used. The NIC may use one or more of the techniques to indicate the availability of packets to transfer. Interrupt-driven I/O is where the peripheral alerts the CPU that it is ready to transfer data, also, NICs may use one or more of the following techniques to transfer packet data, Programmed input/output is where the CPU moves the data to or from the NIC to memory. Direct memory access is where some other device other than the CPU assumes control of the bus to move data to or from the NIC to memory. This removes load from the CPU but requires more logic on the card, in addition, a packet buffer on the NIC may not be required and latency can be reduced. There are two types of DMA, third-party DMA in which a DMA controller other than the NIC performs transfers, an Ethernet network controller typically has an 8P8C socket where the network cable is connected. Older NICs also supplied BNC, or AUI connections, a few LEDs inform the user of whether the network is active, and whether or not data transmission occurs. Ethernet network controllers typically support 10 Mbit/s Ethernet,100 Mbit/s Ethernet, such controllers are designated as 10/100/1000, meaning that they can support a notional maximum transfer rate of 10,100 or 1000 Mbit/s. 10 Gigabit Ethernet NICs are also available, and, as of November 2014, are beginning to be available on computer motherboards, multiqueue NICs provide multiple transmit and receive queues, allowing packets received by the NIC to be assigned to one of its receive queues. The hardware-based distribution of the interrupts, described above, is referred to as receive-side scaling, purely software implementations also exist, such as the receive packet steering and receive flow steering. Examples of such implementations are the RFS and Intel Flow Director, with multiqueue NICs, additional performance improvements can be achieved by distributing outgoing traffic among different transmit queues. By assigning different transmit queues to different CPUs/cores, various operating systems internal contentions can be avoided and those NICs support, Accessing local and remote memory without involving the remote CPU
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Ethernet
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Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE802.3, over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a medium, while the newer Ethernet variants use twisted pair. Over the course of its history, Ethernet data transfer rates have increased from the original 2.94 megabits per second to the latest 100 gigabits per second. The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet, systems communicating over Ethernet divide a stream of data into shorter pieces called frames. As per the OSI model, Ethernet provides services up to, since its commercial release, Ethernet has retained a good degree of backward compatibility. Features such as the 48-bit MAC address and Ethernet frame format have influenced other networking protocols, the primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE802.11. Ethernet was developed at Xerox PARC between 1973 and 1974 and it was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, in 1976, after the system was deployed at PARC, Metcalfe and Boggs published a seminal paper. Metcalfe left Xerox in June 1979 to form 3Com and he convinced Digital Equipment Corporation, Intel, and Xerox to work together to promote Ethernet as a standard. The so-called DIX standard, for Digital/Intel/Xerox, specified 10 Mbit/s Ethernet, with 48-bit destination and source addresses and it was published on September 30,1980 as The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications, version 2 was published in November,1982 and defines what has become known as Ethernet II. Formal standardization efforts proceeded at the time and resulted in the publication of IEEE802.3 on June 23,1983. Ethernet initially competed with two largely proprietary systems, Token Ring and Token Bus, in the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, an Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS, by the early 1990s, Ethernet became so prevalent that it was a must-have feature for modern computers, and Ethernet ports began to appear on some PCs and most workstations. This process was sped up with the introduction of 10BASE-T and its relatively small modular connector. Since then, Ethernet technology has evolved to meet new bandwidth, in addition to computers, Ethernet is now used to interconnect appliances and other personal devices
31.
USRobotics
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U. S. Robotics Corporation, often called USR, is a company that produces USRobotics computer modems and related products. Its initial marketing was aimed at bulletin board systems, where its high-speed HST protocol made FidoNet transfers much faster, during the 1990s it became a major consumer brand with its Sportster line. The company had a reputation for quality and support for the latest communications standards as they emerged, notably in its V. Everything line. With the reduced usage of analog or voiceband modems in North America in the early 21st century, the company purchased Palm, Inc. for its PalmPilot PDA, but was itself purchased by 3Com soon after. 3Com spun off USR again in 2000, keeping Palm and returning USR to the now much smaller modem market, after 2004 the company is formally known as USR. It is one of the few left in the modem market today. The company name is a reference to the fiction of Isaac Asimov, asimovs robot stories featured a fictional company named U. S. Cowell stated at a popular BBS convention they named the company as an homage to Asimov, robots eventually became the biggest company in the universe. USR was one of many companies to offer dial-up modems for personal computers, prior to the development of standards such as the V.32 family of protocols, USR introduced its own HST protocol in 1986, which operated at 9600 bit/s. In 1989 HST was expanded to 14.4 kbit/s,16.8 kbit/s in 1992, however, USR became the most successful of the three, due to a marketing scheme that offered large discounts to BBS sysops. The proprietary nature of HST allowed USR to maintain its market even when off-brand V. 32-based modems began selling for less than equivalent HST modems. As the price decreased, however, V. 32-based modems eventually became a cost-effective alternative to HST. The Sportster used the same motherboard as the Couriers, and on certain 14.4 kbit/s models a sequence of AT commands could be issued to enable the faster 16.8 kbit/s HST mode. The Courier modems remained a favorite in the BBS and emerging Internet service provider world, a similar situation emerged a few years later when the 56kbit/s V.90 standard was first being proposed. USR developed its own 56k standard known as X2, while a consortium of companies introduced its own K56flex. In contrast to the success of HST, neither X2 nor K56flex saw any real market uptake, after the introduction of V.90, USR abandoned support for X2. In a further effort to reduce the price of its modems. Some models of Courier modems were known for their long-term upgradeability, because they used an upgradeable DSP design
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Dell
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Dell Inc. is a multinational computer technology company based in Round Rock, Texas, United States, that develops, sells, repairs, and supports computers and related products and services. The company is a subsidiary of Dell Technologies, which was formed by the 2016 merger of Dell Inc. eponymously named after its founder, Michael Dell, the company is one of the largest technological corporations in the world, employing more than 103,300 people worldwide. Dell sells personal computers, servers, data storage devices, network switches, software, computer peripherals, HDTVs, cameras, printers, MP3 players, and electronics built by other manufacturers. Dell was a pure hardware vendor for much of its existence, Dell was listed at number 51 in the Fortune 500 list, until 2014. After going private in 2013, the confidential nature of its financial information prevents the company from being ranked by Fortune. In 2015, it was the third largest PC vendor in the world after Lenovo, Dell is currently the #1 shipper of PC monitors in the world. Dell is the sixth largest company in Texas by total revenue and it is the second largest non-oil company in Texas – behind AT&T – and the largest company in the Greater Austin area. It was a traded company, as well as a component of the NASDAQ-100 and S&P500. On September 7,2016, Dell Inc. acquired EMC Corporation to form Dell Technologies, Michael Dell founded PCs Limited while a student of the University of Texas at Austin. The dorm-room headquartered company sold IBM PC-compatible computers built from stock components, Dell dropped out of school to focus full-time on his fledgling business, after getting $1,000 in expansion-capital from his family. In 1985, the company produced the first computer of its own design, the Turbo PC, Dell appeared in PCs Limited advertisements in national magazines, asking readers to give us a chance to show you what can do. Selling directly to consumers custom-assembled computers according to a selection of options, in 1986, Michael Dell brought in Lee Walker, a 51-year-old venture capitalist, as president and chief operating officer, to serve as mentor and to implement Dells ideas for growing the company. Walker was also instrumental in recruiting members to the board of directors when the company went public in 1988, the company dropped the PC’s Limited name in 1987 to become Dell Computer Corporation and began expanding globally. In June 1988, Dells market capitalization grew by $30 million to $80 million from its June 22 initial public offering of 3.5 million shares at $8.50 a share. In 1992, Fortune magazine included Dell Computer Corporation in its list of the worlds 500 largest companies, making Michael Dell the youngest CEO of a Fortune 500 company ever. In 1993, to complement its own direct sales channel, Dell planned to sell PCs at big-box retail outlets such as Wal-Mart, bain consultant Kevin Rollins persuaded Michael Dell to pull out of these deals, believing they would be money losers in the long run. Margins at retail were thin at best and Dell left the channel in 1994. Rollins would soon join Dell full-time and eventually become the company President, Dell found an opportunity among PC-savvy individuals who liked the convenience of buying direct, customizing their PC to their means, and having it delivered in days
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Plug and play
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Plug and play devices can be due to boot-time assignment of device resources and to hotplug systems such as USB and IEEE1394. In the beginnings of data processing technology, the hardware was just a collection of modules, and this linking was usually done by connecting some wires between modules and disconnecting others. Some early microcomputing devices such as the Apple II sometimes required the end-user to physically cut some wires, the changes were intended to be largely permanent for the life of the hardware. As computers became more accessible to the public, the need developed for more frequent changes to be made by computer users unskilled with using soldering irons. Rather than cutting and soldering connections, configuration was accomplished by jumpers or DIP switches, however, the process of configuring devices manually using jumpers or DIP switches, could be quite difficult, and there was usually no forgiveness for technical inexperience. Incorrect settings could render either the system or just the expansion device completely or partially inoperable. The system might still have seemed to work properly with a setting, until the IRQ or DMA was actually needed. No jumpers or any manual configuration was required, and the independent address space for each slot allowed very cheap & commonplace chips to be used, alongside with cheap glue logic. On the software site, the drivers and extensions were supplied in the cards own ROM, the ROM extensions abstracted any hardware differences and offered standard APIs as specified by ASCII Corporation. In 1984, the NuBus architecture was developed by the Massachusetts Institute of Technology as a platform agnostic peripheral interface that fully automated device configuration, the specification was sufficiently intelligent that it could work with both big endian and little endian computer platforms that had previously been mutually incompatible. However, this agnostic approach increased interfacing complexity and required support chips on every device which in the 1980s was expensive to do, in 1984, Commodore developed the AutoConfig protocol and the Zorro expansion bus for its Amiga line of expandable computers. The first public appearance was in the CES computer show at Las Vegas in 1985, like NuBus, Zorro devices had absolutely no jumpers or DIP switches. The Zorro architecture did not spread to general computing use outside of the Amiga product line, in 1987, IBM released an update to the IBM PC known as the Personal System/2 line of computers using the Micro Channel Architecture. The PS/2 was capable of totally automatic self-configuration, every piece of expansion hardware was issued with a floppy disk containing a special file used to auto-configure the hardware to work with the computer. The user would install the device, turn on the computer, load the configuration information from the disk, and the hardware automatically assigned interrupts, DMA, and so forth. However, the disks posed a problem if they were damaged or lost, without the disks, any new hardware would be completely useless and the computer would not boot at all until the unconfigured device was removed. Microchannel did not gain support, because IBM wanted to exclude clone manufacturers from this next generation computing platform. Anyone developing for MCA had to sign agreements and pay royalties to IBM for each device sold
34.
Direct memory access
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Direct memory access is a feature of computer systems that allows certain hardware subsystems to access main system memory, independent of the central processing unit. Without DMA, when the CPU is using programmed input/output, it is fully occupied for the entire duration of the read or write operation. This feature is useful at any time that the CPU cannot keep up with the rate of data transfer, many hardware systems use DMA, including disk drive controllers, graphics cards, network cards and sound cards. DMA is also used for data transfer in multi-core processors. Computers that have DMA channels can transfer data to and from devices with much less CPU overhead than computers without DMA channels, DMA can also be used for memory to memory copying or moving of data within memory. DMA can offload expensive memory operations, such as copies or scatter-gather operations. An implementation example is the I/O Acceleration Technology, Standard DMA, also called third-party DMA, uses a DMA controller. A DMA controller can generate memory addresses and initiate memory read or write cycles and it contains several hardware registers that can be written and read by the CPU. These include an address register, a byte count register. To carry out an input, output or memory-to-memory operation, the host processor initializes the DMA controller with a count of the number of words to transfer, the CPU then sends commands to a peripheral device to initiate transfer of data. The DMA controller then provides addresses and read/write control lines to the system memory, each time a byte of data is ready to be transferred between the peripheral device and memory, the DMA controller increments its internal address register until the full block of data is transferred. In a bus mastering system, also known as a first-party DMA system, where a peripheral can become bus master, it can directly write to system memory without involvement of the CPU, providing memory address and control signals as required. Some measure must be provided to put the processor into a hold condition so that bus contention does not occur, DMA transfers can either occur one byte at a time or all at once in burst mode. In burst mode DMA, the CPU can be put on hold while the DMA transfer occurs, when memory cycles are much faster than processor cycles, an interleaved DMA cycle is possible, where the DMA controller uses memory while the CPU cannot. An entire block of data is transferred in one contiguous sequence, the mode is also called Block Transfer Mode. It is also used to stop unnecessary data, the cycle stealing mode is used in systems in which the CPU should not be disabled for the length of time needed for burst transfer modes. However, in cycle stealing mode, after one byte of data transfer and it is then continually requested again via BR, transferring one byte of data per request, until the entire block of data has been transferred. By continually obtaining and releasing the control of the system bus, the CPU processes an instruction, then the DMA controller transfers one data value, and so on
35.
BIOS
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The BIOS is a type of firmware used to perform hardware initialization during the booting process on IBM PC compatible computers, and to provide runtime services for operating systems and programs. The BIOS firmware is built into personal computers, and it is the first software they run when powered on, the name itself originates from the Basic Input/Output System used in the CP/M operating system in 1975. Originally proprietary to the IBM PC, the BIOS has been engineered by companies looking to create compatible systems. The fundamental purposes of the BIOS in modern PCs are to initialize and test the hardware components. Variations in the hardware are hidden by the BIOS from programs that use BIOS services instead of directly accessing the hardware. MS-DOS, which was the dominant PC operating system from the early 1980s until the mid-1990s, relied on BIOS services for disk, keyboard, and text display functions. Most BIOS implementations are specifically designed to work with a computer or motherboard model. This allows easy updates to the BIOS firmware so new features can be added or bugs can be fixed, unified Extensible Firmware Interface was designed as a successor to BIOS, aiming to address its technical shortcomings. As of 2014, new PC hardware predominantly ships with UEFI firmware, together with the underlying hardware-specific, but operating system-independent System BIOS, which resides in ROM, it represents the analogous to the CP/M BIOS. With the introduction of PS/2 machines, IBM divided the System BIOS into real-mode, the BIOS of the original IBM PC XT had no interactive user interface. Options on the IBM PC and XT were set by switches and jumpers on the main board, starting around the mid-1990s, it became typical for the BIOS ROM to include a BIOS configuration utility or BIOS setup utility, accessed at system power-up by a particular key sequence. This program allowed the user to set configuration options, of the type formerly set using DIP switches. The disk was supplied with the computer, and if it was lost the settings could not be changed. Instead of battery-backed RAM, the modern Wintel machine may store the BIOS configuration settings in flash ROM, early Intel processors started at physical address 000FFFF0h. When a modern x86 microprocessor is reset, it starts in pseudo 16-bit real mode, the code segment register is initialized with selector F000h, base FFFF0000h, and limit FFFFh, so that execution starts at 4 GB minus 16 bytes. The platform logic maps this address into the system ROM, mirroring address 000FFFF0h, if the system has just been powered up or the reset button was pressed, the full power-on self-test is run. This saves the time used to detect and test all memory. If the download was apparently successful, the BIOS would verify a checksum on it and then run it
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Operating system
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An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is Microsoft Windows with a market share of around 83. 3%. MacOS by Apple Inc. is in place, and the varieties of Linux is in third position. Linux distributions are dominant in the server and supercomputing sectors, other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can run one program at a time. Multi-tasking may be characterized in preemptive and co-operative types, in preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e. g. Solaris, Linux, cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking, 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem, a distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing, distributed computations are carried out on more than one machine. When computers in a work in cooperation, they form a distributed system. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses, embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy and they are able to operate with a limited number of resources. They are very compact and extremely efficient by design, Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is a system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could run different programs in succession to speed up processing
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Microsoft
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Its best known software products are the Microsoft Windows line of operating systems, Microsoft Office office suite, and Internet Explorer and Edge web browsers. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface tablet lineup, as of 2016, it was the worlds largest software maker by revenue, and one of the worlds most valuable companies. Microsoft was founded by Paul Allen and Bill Gates on April 4,1975, to develop and it rose to dominate the personal computer operating system market with MS-DOS in the mid-1980s, followed by Microsoft Windows. The companys 1986 initial public offering, and subsequent rise in its share price, since the 1990s, it has increasingly diversified from the operating system market and has made a number of corporate acquisitions. In May 2011, Microsoft acquired Skype Technologies for $8.5 billion, in June 2012, Microsoft entered the personal computer production market for the first time, with the launch of the Microsoft Surface, a line of tablet computers. The word Microsoft is a portmanteau of microcomputer and software, Paul Allen and Bill Gates, childhood friends with a passion for computer programming, sought to make a successful business utilizing their shared skills. In 1972 they founded their first company, named Traf-O-Data, which offered a computer that tracked and analyzed automobile traffic data. Allen went on to pursue a degree in science at Washington State University. The January 1975 issue of Popular Electronics featured Micro Instrumentation and Telemetry Systemss Altair 8800 microcomputer, Allen suggested that they could program a BASIC interpreter for the device, after a call from Gates claiming to have a working interpreter, MITS requested a demonstration. Since they didnt actually have one, Allen worked on a simulator for the Altair while Gates developed the interpreter and they officially established Microsoft on April 4,1975, with Gates as the CEO. Allen came up with the name of Micro-Soft, as recounted in a 1995 Fortune magazine article. In August 1977 the company formed an agreement with ASCII Magazine in Japan, resulting in its first international office, the company moved to a new home in Bellevue, Washington in January 1979. Microsoft entered the OS business in 1980 with its own version of Unix, however, it was MS-DOS that solidified the companys dominance. For this deal, Microsoft purchased a CP/M clone called 86-DOS from Seattle Computer Products, branding it as MS-DOS, following the release of the IBM PC in August 1981, Microsoft retained ownership of MS-DOS. Since IBM copyrighted the IBM PC BIOS, other companies had to engineer it in order for non-IBM hardware to run as IBM PC compatibles. Due to various factors, such as MS-DOSs available software selection, the company expanded into new markets with the release of the Microsoft Mouse in 1983, as well as with a publishing division named Microsoft Press. Paul Allen resigned from Microsoft in 1983 after developing Hodgkins disease, while jointly developing a new OS with IBM in 1984, OS/2, Microsoft released Microsoft Windows, a graphical extension for MS-DOS, on November 20,1985. Once Microsoft informed IBM of NT, the OS/2 partnership deteriorated, in 1990, Microsoft introduced its office suite, Microsoft Office
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