IBM PC compatible





IBM PC compatible refers to a class of computers which make up the vast
majority of smaller computers (microcomputers) on the market today. They are
based on the original IBM PC, use the Intel x86 architecture and are
capabable of using interchangable commodity hardware.

The origins of this platform came with the decision by IBM in 1981 to market
a personal computer as quickly as possible. In licensing an operating system
from Microsoft, IBM's agreements allowed Microsoft to sell DOS for non-IBM
platforms. Also, in creating the platform, IBM used only one proprietary
component: the BIOS.

Compaq Computer Corporation manufactured the first non-IBM IBM PC compatible
in 1984. Compaq could not directly copy the BIOS as a result of the court
decision in Apple v. Franklin, but it could reverse-engineer the IBM BIOS
and then write its own BIOS using clean room design.

Since 1984, IBM PC compatibles have conquered both the home and business
markets of commodity computers so that the only notable remaining
competition comes from Apple Macintosh computers with a market share of only
a few per cent. Meanwhile, IBM has lost ground in the market for IBM PC
compatibles; currently (as of 2003) major market players include Dell, HP,
and IBM.

Despite advances in computer technology, all current IBM PC compatibles
remain very much compatible with the original IBM PC computers, although
most of the components implement the compatibility in special backward
compatibility modes used only during a system boot.