IBM Personal Computer: Difference between revisions

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The '''IBM PC''' (Personal Computer) is a trade mark of [[IBM]].

Due to the success of the IBM PC, the generic term ''Personal Computer'' became common for all [[microcomputer]]s compatible with IBM's specification (see [[IBM PC compatible]]),. and The term is oftensometimes extended to mean all microcomputers. For a discussion of Personal Computers in general, see [[personal computer]].

*For a discussion of generic "Personal Computers", see [[personal computer]].

IBM PCs and compatible models from other vendors are the most widely used [[computer]] systems in the world. They are typically single user [[personal computer]]s, although they have been adapted into multi-user models for special applications.

*For details of the first generation of microcomputers that largely died out with the Personal Computer revolution, see [[home computer]]s.

== The IBM PC Concept ==

The original PC was an IBM attempt to get into the home computer market then dominated by the [[Apple II]].

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 were assembled to bypass normal company restrictions and get soemthing to market rapidly. The 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 for a variety of different Original Equipment Manufacturers (OEM)s and countries. Previously IBM had developed their own components. Second they decided on an open [[Computer architecture|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 licencing the BIOS, and by keeping ahead of the competition.

Unfortunately for IBM, other manufacturers rapidly [[reverse engineering|reverse engineered]] the BIOS to produce their own royalty-free versions. And one the PC became a commercial success the PC came back under 'normal' IBM mangement control, with the result that competitors had little trouble taking the lead from IBM.

== Commercial Success ==

The first ''IBM PC'' was released on August 12 [[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 mangers 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 leared at business school. The personal computer revolution was born.

== IBM PC Models ==

== Models ==

The models of IBM's first-generation Personal Computer (PC) series have names:

* The original PC was an IBM attempt to get into the home computer market then dominated by the [[Apple II]]. It had a version of [[BASIC]] in [[ROM]]. The [[CGA]] (Colour Graphics Adapter) video card could use a standard [[Television|TV]] for display. The standard storage device was cassette tape. [[Floppy disk]] was an optional extra; no [[hard disk]] was available. It had only five expansion slots; maximum memory using IBM parts was 256 K, 64 on the main board and three 64 K expansion cards. The processor was an [[Intel 8088]] running at 4.77 [[MHz]].

* The original PC failed miserably in the home market, but was widely used in business. The PC XT was an enhanced machine designed for business use. It had 8 expansion slots and a 10 [[megabyte]] [[hard disk]]. It could take 256 K of memory on the main board. It was usually sold with an [[MDA]] (Monochrome Display Adapter). The processor was still a 4.77 [[MHz]] [[Intel 8088]] and the expansion [[computer bus|bus]] still 8-bit [[ISA]] with [[XT bus architecture]].

* The PC AT used an [[Intel 80286]] processor, originally at 6 MHz and later 8. It had a 16-bit ISA bus and 20 [[meg]] harddrive. IBM made some attempt at marketing it as a multi-user machine, but it sold mainly as a faster PC for power users.

* [[IBM Convertible]]