Editing IBM PC compatible (section)

== Overview ==
These "clones" duplicated almost all the significant features of the original IBM PC architectures. This was facilitated by IBM's choice of [[Commercial off-the-shelf|commodity hardware components]], which were cheap, and by various manufacturers' ability to [[Reverse engineering|reverse-engineer]] the [[BIOS]] [[firmware]] using a "[[clean room design]]" technique. [[Columbia Data Products]] built the first clone of the IBM [[personal computer]], the [[MPC 1600]]<ref>{{cite news | url=https://archive.org/stream/byte-magazine-1982-10/1982_10_BYTE_07-10_Computers_in_Business#page/n81/mode/2up | title=Check The Chart Before You Choose Your New 16-Bit Computer System. | work=BYTE | date=October 1982 | accessdate=July 15, 2021 | author=Advertisement | pages=83}}</ref> by a clean-room reverse-engineered implementation of its BIOS. Other rival companies, [[Corona Data Systems]], [[Eagle Computer]], and the Handwell Corporation were threatened with legal action by IBM, who settled with them. Soon after in 1982, [[Compaq]] released the very successful [[Compaq Portable]], also with a clean-room reverse-engineered BIOS, and also not challenged legally by IBM.
[[File:Computer lab showing desktop PCs warwick.jpg|thumb|Almost all home computers since the 1990s are technically IBM PC-compatibles.]]
Early IBM PC compatibles used the same [[Bus (computing)|computer buses]] as their IBM counterparts, switching from the [[8-bit computing|8-bit]] IBM PC and XT bus to the [[16-bit computing|16-bit]] IBM AT bus with the release of the AT. IBM's introduction of the proprietary [[Micro Channel architecture]] (MCA) in its [[IBM PS/2|Personal System/2]] (PS/2) series resulted in the establishment of the [[Extended Industry Standard Architecture]] bus [[open standard]] by a consortium of IBM PC compatible vendors, redefining the 16-bit IBM AT bus as the [[Industry Standard Architecture]] (ISA) bus.<ref>Compaq Leads 'Gang of Nine' In Offering Alternative to MCA, ''InfoWorld'', September 19, 1988.</ref> Additional bus standards were subsequently adopted to improve compatibility between IBM PC compatibles, including the [[VESA Local Bus]] (VLB), [[Peripheral Component Interconnect]] (PCI), and the [[Accelerated Graphics Port]] (AGP).

Descendants of the x86 IBM PC compatibles, namely [[64-bit computing|64-bit]] computers based on "[[x86-64]]/AMD64" chips [[Influence of the IBM PC on the personal computer market|comprise the majority of desktop computers]] on the market as of 2021, with the dominant [[operating system]] being [[Microsoft Windows]]. Interoperability with the bus structure and peripherals of the original PC architecture may be limited or non-existent. Many modern computers are unable to use old software or hardware that depends on portions of the IBM PC compatible architecture which are missing or do not have equivalents in modern computers. For example, computers which boot using [[Unified Extensible Firmware Interface]]-based firmware that lack a Compatibility Support Module, or CSM, required to emulate the old BIOS-based firmware interface, or have their CSMs disabled, cannot natively run [[MS-DOS]] since MS-DOS depends on a BIOS interface to boot.

Only the [[Mac (computer)|Macintosh]] had kept significant market share without having compatibility with the IBM PC, although that changed during the Intel Macs era running [[MacOS|Mac OS X]], often [[dual-booting]] Windows with [[Boot Camp (software)|Boot Camp]].