IBM Personal Computer: Difference between revisions

Revision as of 06:19, 29 June 2003

Revision as of 17:30, 9 July 2003

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

'''IBM PCs''' ([[IBM]] [[Personal Computer|Personal Computers]]) 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.

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

'''IBM PCs''' ([[IBM]] [[Personal Computer|Personal Computers]]) 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.

== Models ==

There are hundreds of models of [[IBM compatible]] computers. 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.

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The original IBM PC used the 7 bit [[ASCII]] alphabet as the basis, but in addition this was extended to am 8 bit somewhat haphazardly collected set of characters unique for the IBM PC. This set was not really suitable for international use, 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, being replaced by more well thought out schemes for character coding, like the [[ISO 8859-1]] and [[Unicode]].

==== Storage mediumsmedia ====

Technically, the standard storage medium for the original IBM PC model 5150 was a cassette port. Being pretty much obsolete even by [[1981]] standards, very few, if any, IBM PC probably left the factory without a floppy disk drive installed. The 1981 PC had one or two 360 [[kilobyte]] 5 1/4 inch single sided double density [[floppy disk]] drives.

In 1984, IBM introduced the 1.2 megabyte dual sided floppy disk along with its AT model. Although often used as backup storage, the high density floppy was not often used for interchangeability. In 1986, IBM introduced the 720 kilobyte 3.5" microfloppy disk on its Convertible laptop computer. It introduced the 1.44 megabyte [[double density]] version with the PS/2 line. These disk drives could be added to existing older model PCs.

The first IBM PC that included a fixed, non-removable, [[hard disk|hard disks]] was the XT. Hard disks for IBM compatibles are now available with very large storage capacities. If a hard disk is added that is not compatible with the existing [[disk controller]], a new controller board must be plugged in. However, one disk's internal standard does not conflict with another, since all programs and data must be copied onto it to begin with.

The first IBM PC that included a

fixed, non-removable, [[hard disk|hard disks]] was the XT. Hard disks

for IBM compatibles are now available with very large storage capacities. If a hard disk is added that is not compatible with the existing [[disk controller]], a new controller board must be plugged in. However, one disk's internal standard does not conflict with another, since all programs and data must be copied onto it to begin with.

=== Software ===