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The IBM PC™ ('''''P'''ersonal '''C'''omputer''), was the original version and progenitor of the IBM PC Compatible hardware Platform . It was introduced on August 11 , 1981 . The original model was designated the '''IBM 5150'''. It was created by a team of 12 engineers and designers under the direction of Don Estridge of the IBM Entry Systems Division in Boca Raton, Florida . The phrase "personal computer" was common currency before 1981, and was used as early as 1972 to characterize Xerox PARC 's Alto . However, due to the success of the IBM PC, what had been a generic term came to mean specifically a Microcomputer compatible with IBM's specification. During the second quarter of 2005 , the Chinese Lenovo Group secured the rights to produce IBM branded personal computers. This move reflects IBM's present lack of interest in the personal computer in favor of the Server / Mainframe markets, as well as providing Business Consulting and IT Services markets. ''Note the following distinctions within the general subject of personal computers'':
THE IBM PC CONCEPT The original ''PC'' was an IBM attempt to get into the home computer market then dominated by the Apple II and a host of CP/M machines. Rather than going through the usual IBM design process, which had already failed to design an affordable microcomputer (for example the failed IBM 5100 ), a special team was assembled with authorization to bypass normal company restrictions and get something to market rapidly. This project was given the code name ''Project Chess''. The team consisted of just 12 people headed by William Lowe. They succeeded — development of the PC took about a year. To achieve this they first decided to build the machine with "off-the-shelf" parts from a variety of different Original Equipment Manufacturer s (OEMs) and countries. Previously IBM had developed their own components. Second they decided on an open Architecture so that other manufacturers could produce and sell compatible machines — the IBM PC Compatible s, so the specification of the ROM BIOS was published. IBM hoped to maintain their position in the market by royalties from licensing the BIOS, and by keeping ahead of the competition. Unfortunately for IBM, other manufacturers rapidly Reverse Engineered the BIOS to produce their own royalty-free versions. Compaq Computer Corporation announced the first cloned IBM PC Compatible in November 1982 (it did not ship until March 1983 ) — the '' Compaq Portable ''. Not only was it the first '' IBM-PC Compatible '' computer not manufactured by IBM , it was also the first ever '' IBM-PC Compatible '' Portable Computer . Once the ''IBM PC'' became a commercial success the ''PC'' came back under the usual IBM management control, with the result that competitors had little trouble taking the lead from them. (In this regard, IBM's tradition of "rationalizing" their product lines—deliberately restricting the performance of lower-priced models in order to prevent them from "cannibalizing" profits from higher-priced models—worked against them). COMMERCIAL SUCCESS The first ''IBM PC'' was released on August 11 1981 . Although not cheap, at a base price of $1,565 it was affordable for businesses — and it was business that purchased the PC. However it was not the corporate "computer department" that was responsible for this, for the PC was not seen as a 'proper' computer. It was generally well educated middle managers that saw the potential — once the revolutionary VisiCalc spreadsheet, the " Killer App ", had been ported to the PC. Reassured by the IBM name, they began buying the machines on their own budgets to help do the calculations they had learned at business school. IBM PC MODELS The models of IBM's first-generation Personal Computer (PC) series have names:
The models of its second generation, the , Model 30 . Within each series, the models are also commonly referenced by their CPU Clock Rate . All IBM personal computers are Software compatible with each other in general, but not every program will work in every machine. Some programs are time sensitive to a particular speed class. Older programs will not take advantage of newer higher-resolution display standards. TECHNOLOGY Electronics The main circuit board in an IBM PC is called the Motherboard . This carries the CPU and Memory , and has a Bus with slots for expansion cards. The bus used in the original PC became very popular, and was subsequently named ISA . It is in use to this day in computers for industrial use. Later, requirements for higher speed and more capacity forced the development of new versions. IBM introduced the MCA bus with the PS/2 line. The VESA Local Bus allowed for up to three, much faster 32-bit cards, and the EISA architecture was developed as a backward compatible standard including 32-bit card slots, but it only sold well in high-end server systems. The lower-cost and more general PCI bus was introduced in 1994 and has now become ubiquitous. The motherboard is connected by cables to internal storage devices such as Hard Disk s, Floppy Disk s and CD-ROM drives. These tend to be made in standard sizes, such as 3.5" (90 mm) and 5.25" (133.4 mm) widths, with standard fixing holes. The case also contains a standard Power Supply unit (PSU) which is either an AT or ATX standard size. Intel 8086 and 8088 -based PCs require EMS (expanded memory) boards to work with more than one Megabyte of memory. The original IBM PC AT used an Intel 80286 processor which can access up to 16 megabytes of memory (though standard DOS applications cannot use more than one megabyte without using additional APIs.) Intel 80286-based computers running under OS/2 can work with the maximum memory. Keyboard The original 1981 IBM PC's Keyboard was severely criticised by typists for its non-standard placement of the return and left shift keys. In 1984 , IBM corrected this on its AT keyboard, but shortened the backspace key, making it harder to reach. In 1987 , it introduced the Enhanced Keyboard , which relocated all the function keys and the Ctrl keys. The Esc key was also relocated to the opposite side of the keyboard. An "IBM PC compatible" may have a keyboard which does not recognize every key combination a true IBM PC does, e.g. shifted cursor keys. In addition, the "compatible" vendors sometimes used proprietary keyboard interfaces, preventing you from replacing the keyboard. ''See also'': Keyboard Layout Character set The original IBM PC used the 7-bit ASCII alphabet as its basis, but extended it to 8 bits with nonstandard character codes. This character set was not suitable for some international applications, and soon a veritable cottage industry emerged providing variants of the original character set in various national variants. In IBM tradition, these variants were called Code Page s. These codings are now obsolete, having been replaced by more systematic and standardized forms of character coding, such as ISO 8859-1 , Windows-1251 and Unicode . This was the original IBM PC character set:
# Under DOS, RAM is expanded beyond 1 MB with EMS memory boards # Under DOS, RAM is expanded beyond 1 MB with normal " Extended " memory and a memory management program. SEE ALSO
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