IBM compatible PC

The concept of an IBM compatible PC reaches back to 1983, to a radical decision made by IBM when it introduced its first personal x86-based personal computer. To widespread industry amazement, IBM published the behavioral specifications of their PC and openly encouraged other companies could build components for it, or even create an entirely different incarnation of the hardware which would run the same software. Compaq, around 1985, was the first company to succeed in creating a fully IBM-compatible instance.

This decision to maintain backward compatibility of hardware and software laid the groundwork for the subsequent success of the x86 family of microprocessors, and the IBM compatible PCs which contain them.