IBM PC Compatibility
The concept of IBM PC compatibility refers to the ability of a computer to operate with the same software, utilize the same peripheral devices, and function in the same hardware environment as the original IBM Personal Computer. This compatibility became a defining characteristic of personal computing in the years following the release of the IBM PC in 1981, leading to a widespread market of PC clones that have continued to influence home and business computing.
Historical Context
The IBM Personal Computer, model 5150, was the first in a line of personal computers introduced by IBM that included subsequent models such as the IBM PCjr and the IBM Personal Computer AT. The open architecture of these computers allowed other manufacturers to create compatible hardware and software, giving rise to the term "IBM PC compatibility."
Key Characteristics
An IBM PC compatible computer typically uses an x86-based central processing unit, originally designed by Intel Corporation, but also sourced from companies like AMD, Cyrix, and others. These systems could support interchangeable commodity hardware, such as expansion cards, allowing extensive versatility and scalability.
Expansion and Architecture
The early adoption of the Industry Standard Architecture (ISA) bus played a significant role in the compatibility of IBM PC systems. IBM's introduction of the Micro Channel Architecture (MCA) in the Personal System/2 series led to the establishment of the Extended Industry Standard Architecture (EISA) bus, developed by a consortium of IBM PC compatible vendors.
Impact on the Market
The release of the IBM PC and its successors led to a flourishing market for IBM PC compatible systems. Many personal computer architectures that existed prior to the IBM PC were phased out, leading to a wave of "IBM clones," such as the Tandy 1000, which were marketed as lower-cost alternatives to IBM's own machines. This trend dictated the direction of the personal computer market for decades.
End of an Era
IBM's divestiture from the personal computer business in 2005, with the sale of its PC division to Lenovo, marked an end of direct involvement in a market that it had once dominated. Nonetheless, the legacy of IBM PC compatibility remains significant, as it established a standard for personal computing that persists in modern computing systems.