IBM PC compatible
![The original IBM PC (Model 5150) motivated the production of clones during the early 1980s.](/Images/godic/202502/01/IBM_PC_51504226.jpg")
![The Compaq Portable was the first 100% IBM-compatible PC, and the first portable one.](/Images/godic/202502/01/Compaq_portable4226.jpg")
![MS-DOS version 1.12 for Compaq Personal Computers](/Images/godic/202502/01/Compaq_mddos_ver1-124226.jpg")
![PC compatibility was an important concern. Even the Commodore Amiga 1000 had a PC compatible add-on module, the Sidecar.](/Images/godic/202502/01/Amiga_1000_system_with_sidecar4226.jpg")
IBM PC compatible computers are those similar to the original IBM PC, XT, and AT, able to run the same software and support the same expansion cards as those. Such computers used to be referred to as PC clones, or IBM clones. They duplicate almost exactly all the significant features of the PC architecture, facilitated by IBM's choice of commodity hardware components and various manufacturers' ability to reverse engineer the BIOS firmware using a "clean room design" technique. Columbia Data Products built the first clone of the IBM personal computer by a clean room implementation of its BIOS.