Editing IBM PC compatible

{{short description|Computers similar to the IBM PC and its derivatives}}
{{Use mdy dates|date=January 2023}}
{{Use American English|date=January 2023}}
[[File:Compaq portable.jpg|thumb|right|The [[Compaq Portable]] was one of the first nearly 100% IBM-compatible PCs.]]

An '''IBM PC compatible''' is any [[personal computer]] that is [[Computer hardware|hardware]]- and [[software]]-compatible with the [[IBM Personal Computer]] (IBM PC) and its [[List of IBM Personal Computer models|subsequent models]]. Like the original IBM PC, an IBM PC–compatible computer uses an [[x86]]-based [[central processing unit]], sourced either from [[Intel]] or a [[second source]] like [[AMD]], [[Cyrix]] or [[Intel_8086#Derivatives_and_clones|other vendors]] such as [[Texas Instruments]], [[Fujitsu]], [[OKI (company)|OKI]], [[Mitsubishi]] or [[NEC]] and is capable of using interchangeable commodity hardware such as [[expansion card]]s. Initially such computers were referred to as '''PC clones''', '''IBM clones''' or '''IBM PC clones''', but the term "IBM PC compatible" is now a historical description only, as the vast majority of [[microcomputers]] produced since the 1990s are IBM compatible. [[IBM]] itself no longer sells personal computers, [[Acquisition of the IBM PC business by Lenovo|having sold its division]] to [[Lenovo]] in 2005. "[[Wintel]]" is a similar description that is more commonly used for modern computers. 

The designation "PC", as used in much of [[History of personal computers|personal computer history]], has not meant "personal computer" generally, but rather an x86 computer capable of running the same software that a contemporary IBM or Lenovo PC could. The term was initially in contrast to the variety of [[home computer]] systems available in the early 1980s, such as the [[Apple II]], [[TRS-80]], and [[Commodore 64]]. Later, the term was primarily used in contrast to [[Commodore International|Commodore]]'s [[Amiga]] and [[Apple Inc.|Apple]]'s [[Mac (computer)|Macintosh]] computers.

== 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]].

==Origins==
[[File:IBM PC 5150.jpg|thumb|right|250px|The original [[IBM Personal Computer|IBM PC]] (Model 5150) motivated the production of clones during the early 1980s.]]

IBM decided in 1980 to market a low-cost single-user computer as quickly as possible. On August 12, 1981, the first [[IBM Personal Computer|IBM PC]] went on sale. There were three [[operating system]]s (OS) available for it. The least expensive and most popular was [[IBM PC DOS|PC DOS]] made by [[Microsoft]]. In a crucial concession, IBM's agreement allowed Microsoft to sell its own version, [[MS-DOS]], for non-IBM computers. The only component of the original PC architecture exclusive to IBM was the [[BIOS]] (Basic Input/Output System).

IBM at first asked developers to avoid writing software that addressed the computer's hardware directly and to instead make standard calls to BIOS functions that carried out hardware-dependent operations.<ref name="norton19850205">{{cite news |url=https://books.google.com/books?id=BGNWNTJnuRcC&pg=PA101 | title=Software for Once and All | work=PC Magazine | date=February 5, 1985 | access-date=October 28, 2013 | author=Norton, Peter | pages=103}}</ref> This software would run on any machine using MS-DOS or PC DOS. Software that directly addressed the hardware instead of making standard calls was faster, however; this was particularly relevant to games. Software addressing IBM PC hardware in this way would not run on MS-DOS machines with different hardware (for example, the [[PC-98]]). The IBM PC was sold in high enough volumes to justify writing software specifically for it, and this encouraged other manufacturers to produce machines that could use the same programs, [[expansion card]]s, and peripherals as the PC. The [[x86]] computer marketplace rapidly excluded all machines which were not hardware-compatible or software-compatible with the PC. The [[Conventional memory#640 KB barrier|640&nbsp;KB barrier]] on "conventional" system memory available to MS-DOS is a legacy of that period; other non-clone machines, while subject to a limit, could exceed 640&nbsp;KB.

Rumors of "lookalike," compatible computers, created without IBM's approval, began almost immediately after the IBM PC's release.<ref name="libes198112">{{cite news | url=https://archive.org/stream/byte-magazine-1981-12/1981_12_BYTE_06-12_Computer_Games#page/n315/mode/2up | title=Bytelines | work=BYTE | date=December 1981 | access-date=January 29, 2015 | author=Libes, Sol | pages=314–318}}</ref><ref name="pclookalikes19820203">{{cite news |url=https://books.google.com/books?id=w_OhaFDePS4C&pg=PA5 | title=Lookalikes From Home & Abroad | work=PC Magazine | date=February–March 1982 | access-date=October 20, 2013 | pages=5}}</ref> ''InfoWorld'' wrote on the first anniversary of the IBM PC that<ref name="zussman19820823">{{cite news | url=https://books.google.com/books?id=VDAEAAAAMBAJ&pg=PA29 | title=Let's keep those systems open | work=InfoWorld | date=August 23, 1982 | access-date=January 29, 2015 | author=Zussman, John Unger | page=29}}</ref>

{{quote|The dark side of an open system is its imitators. If the specs are clear enough for you to design peripherals, they are clear enough for you to design imitations. Apple ... has patents on two important components of its systems ... IBM, which reportedly has no special patents on the PC, is even more vulnerable. Numerous PC-compatible machines—the grapevine says ''60'' or more—have begun to appear in the marketplace.}}

By June 1983 ''[[PC Magazine]]'' defined "PC 'clone{{'"}} as "a computer [that can] accommodate the user who takes a disk home from an IBM PC, walks across the room, and plugs it into the 'foreign' machine".<ref name="sandler198306">{{cite news |url=https://books.google.com/books?id=14Kfbrc6cbAC&q=pc%20mag%20june%201983&pg=PA31 | title=Getting To Know You | work=PC Magazine | date=June 1983 | access-date=October 21, 2013 | author=Sandler, Corey | pages=31}}</ref> Demand for the PC by then was so strong that dealers received 60% or less of the inventory they wanted,<ref name="hayes19831024">{{Cite news |url=https://www.nytimes.com/1983/10/24/business/eagle-computer-stays-in-the-race.html |title=Eagle Computer Stays in the Race |last=Hayes |first=Thomas C. |date=1983-10-24 |work=The New York Times |access-date=10 January 2015 |page=D4 |url-access=limited}}</ref> and many customers purchased clones instead.<ref name="barmash19830610">{{Cite news |url=https://www.nytimes.com/1983/06/10/business/corporate-triumph-then-death-in-a-ferrari.html |title=Corporate Triumph, Then Death in a Ferrari |last=Barmash |first=Isadore |date=June 10, 1983 |work=The New York Times |access-date=June 19, 2019 |page=A1 |language=en-US |issn=0362-4331}}</ref>{{r|mace19840109_16}}<ref name="pc19840124">{{cite news |url=https://books.google.com/books?id=kSzKzjWHeVEC&pg=PA39 | title=PC-Compatible Portables | work=PC Magazine | date=January 24, 1984 | access-date=October 23, 2013 |author1=Cook, Karen |author2=Langdell, James | pages=39}}</ref> [[Columbia Data Products]] produced the first computer more or less compatible with the IBM PC standard during June 1982, soon followed by [[Eagle Computer]]. [[Compaq]] announced its first product, an IBM PC compatible in November 1982, the [[Compaq Portable]]. The Compaq was the first sewing machine-sized [[portable computer]] that was essentially 100% PC-compatible. The court decision in ''[[Apple Computer, Inc. v. Franklin Computer Corp.|Apple v. Franklin]]'', was that BIOS code was protected by copyright law, but it could [[reverse engineering|reverse-engineer]] the IBM BIOS and then write its own BIOS using [[clean room design]]. Note this was over a year after Compaq released the Portable. The money and research put into reverse-engineering the BIOS was a calculated risk.

==Compatibility issues==
{{See also|Influence of the IBM PC on the personal computer market}}

===Non-compatible MS-DOS computers: Workalikes===
[[File:DEC Rainbow 100.jpg|thumb|The DEC [[Rainbow 100]] runs MS-DOS but is not compatible with the IBM PC.]]

At the same time, many manufacturers such as [[Tandy Corporation|Tandy]]/[[RadioShack]], [[Xerox]], [[Hewlett-Packard]], [[Digital Equipment Corporation]], [[Sanyo]], [[Texas Instruments]], [[Tulip Computers|Tulip]], [[Wang Laboratories|Wang]] and [[Olivetti]] introduced personal computers that supported MS-DOS, but were not completely software- or hardware-compatible with the IBM PC.

Tandy described the [[Tandy 2000]], for example, as having a "'next generation' true 16-bit CPU", and with "More speed. More disk storage. More expansion" than the IBM PC or "other MS-DOS computers".<ref>{{cite web|title=Radio Shack Computer Catalog RSC-12, page 4|url=http://www.radioshackcatalogs.com/html/catalogs_extra/1985_rsc-12/hr004.html|website=radioshackcatalogs dot com|publisher=Tandy/Radio Shack|access-date=June 27, 2017|archive-date=October 3, 2014|archive-url=https://web.archive.org/web/20141003155302/http://www.radioshackcatalogs.com/html/catalogs_extra/1985_rsc-12/hr004.html|url-status=dead}}</ref> While admitting in 1984 that many PC DOS programs did not work on the computer, the company stated that "the most popular, sophisticated software on the market" was available, either immediately or "over the next six months".<ref>{{cite web|title=Radio Shack Computer Catalog RSC-11, page 6|url=http://www.radioshackcatalogs.com/html/catalogs_extra/1984_rsc-11/h006.html|website=radioshackcatalogs dot com|publisher=Tandy/Radio Shack|access-date=June 27, 2017|archive-date=October 3, 2014|archive-url=https://web.archive.org/web/20141003154718/http://www.radioshackcatalogs.com/html/catalogs_extra/1984_rsc-11/h006.html|url-status=dead}}</ref>

Like IBM, Microsoft's apparent intention was that application writers would write to the [[application programming interface]]s in MS-DOS or the firmware BIOS, and that this would form what would now be termed a [[Hardware abstraction|hardware abstraction layer]]. Each computer would have its own [[Original equipment manufacturer|Original Equipment Manufacturer]] (OEM) version of MS-DOS, customized to its hardware. Any software written for MS-DOS would operate on any MS-DOS computer, despite variations in hardware design.

This expectation seemed reasonable in the computer marketplace of the time. Until then Microsoft's business was based primarily on computer languages such as [[BASIC]]. The established small system operating software was [[CP/M]] from [[Digital Research]] which was in use both at the hobbyist level and by the more professional of those using microcomputers. To achieve such widespread use, and thus make the product viable economically, the OS had to operate across a range of machines from different vendors that had widely varying hardware. Those customers who needed other applications than the starter programs could reasonably expect publishers to offer their products for a variety of computers, on suitable media for each.

Microsoft's competing OS was intended initially to operate on a similar varied spectrum of hardware, although all based on the 8086 processor. Thus, MS-DOS was for several years sold only as an OEM product. There was no Microsoft-branded MS-DOS: MS-DOS could not be purchased directly from Microsoft, and each OEM release was packaged with the [[trade dress]] of the given PC vendor. Malfunctions were to be reported to the OEM, not to Microsoft. However, as machines that were compatible with IBM hardware—thus supporting direct calls to the hardware—became widespread, it soon became clear that the OEM versions of MS-DOS were virtually identical, except perhaps for the provision of a few utility programs.

MS-DOS provided adequate functionality for character-oriented applications such as those that could have been implemented on a text-only [[computer terminal|terminal]]. Had the bulk of commercially important software been of this nature, low-level hardware compatibility might not have mattered. However, in order to provide maximum performance and leverage hardware features (or work around hardware bugs), PC applications quickly developed beyond the simple terminal applications that MS-DOS supported directly. [[Spreadsheet]]s, [[WYSIWYG]] [[word processor]]s, [[Presentation program|presentation software]] and remote [[communication software]] established new markets that exploited the PC's strengths, but required capabilities beyond what MS-DOS provided. Thus, from very early in the development of the MS-DOS software environment, many significant commercial software products were written directly to the hardware, for a variety of reasons:
* MS-DOS itself did not provide any way to position the text cursor other than to advance it after displaying each letter ([[teleprinter|teletype mode]]). While the BIOS video interface routines were adequate for rudimentary output, they were necessarily less efficient than direct hardware addressing, as they added extra processing; they did not have "string" output, but only character-by-character teletype output, and they inserted delays to prevent [[Color Graphics Adapter|CGA]] hardware "snow" (a display artifact of CGA cards produced when writing directly to screen memory)——an especially bad artifact since they were called by [[Interrupt request (PC architecture)|IRQs]], thus making multitasking very difficult. A program that wrote directly to video memory could achieve output rates 5 to 20 times faster than making [[system call]]s. [[Turbo Pascal]] used this technique from its earliest versions.
* [[Computer graphics|Graphics]] capability was not taken seriously in the original IBM design brief; graphics were considered only from the perspective of generating static business graphics such as charts and graphs. MS-DOS did not have an [[Application programming interface|API]] for graphics, and the BIOS only included the rudimentary graphics functions such as changing screen modes and plotting single points. To make a BIOS call for every point drawn or modified increased overhead considerably, making the BIOS interface notoriously slow. Because of this, [[line drawing algorithm|line-drawing]], arc-drawing, and [[Bit blit|blitting]] had to be performed by the application to achieve acceptable speed, which was usually done by bypassing the BIOS and accessing video memory directly. Software written to address IBM PC hardware directly would run on any IBM clone, but would have to be rewritten especially for each non-PC-compatible MS-DOS machine.
* [[Video game]]s, even early ones, mostly required a [[Computer display standard|true graphics mode]]. They also performed any machine-dependent trick the programmers could think of in order to gain speed. Though initially the major market for the PC was for business applications, games capability became an important factor motivating PC purchases as prices decreased. The availability and quality of games could mean the difference between the purchase of a PC compatible or a different platform with the ability to exchange data like the [[Amiga]].
* Communications software directly accessed the [[Universal asynchronous receiver-transmitter|UART]] serial port chip, because the MS-DOS API and the BIOS did not provide full support and was too slow to keep up with hardware which could transfer data at 19,200&nbsp;bit/s.
* Even for standard business applications, speed of execution was a significant competitive advantage. [[Integrated software]] [[Context MBA]] preceded [[Lotus 1-2-3]] to market and included more functions. Context MBA was written in [[UCSD Pascal|UCSD p-System]], making it very portable but too slow to be truly usable on a PC. 1-2-3 was written in x86 assembly language and performed some machine-dependent tricks. It was so much faster that it quickly surpassed Context MBA's sales.
* Disk [[copy protection|copy-protection]] schemes, in common use at the time, worked by reading nonstandard data patterns on the diskette to verify originality. These patterns were impossible to detect using standard DOS or BIOS calls, so direct access to the disk controller hardware was necessary for the protection to work.
* Some software was designed to run only on a true IBM PC, and checked for an actual IBM BIOS.{{r|pournelle198411}}

== First-generation PC workalikes by IBM competitors ==
{|class="wikitable sortable"
! Computer name
! Manufacturer
! Date introduced
! CPU
! clock rate
! Max RAM
! Floppy disk capacity
! Notable features
|-
| [[Hyperion (computer)|Hyperion]]
| Dynalogic
| {{Date table sorting|1983|Jan}}
| 8088
| 4.77&nbsp;MHz
| 640 KB
| 320 KB 
| Canadian, licensed<ref>{{cite web|url=https://books.google.com/books?id=amQldGdl9LkC&pg=RA1-PA58|title=Commodore Launches PC-Compatible Abroad|work=PC Magazine|date=June 12, 1984}}</ref><ref>{{cite web|url=https://books.google.com/books?id=h9RnfyXzV6sC&pg=PA52|title=Commodore Adds Hyperion, Chips|author=Karen Cook|work=PC Magazine|date= April 17 – May 1, 1984}}</ref> but never sold{{citation needed|date=September 2024}} by [[Commodore International|Commodore]]<ref>{{cite web|url=https://books.google.com/books?id=lC4EAAAAMBAJ&pg=PA14|title=Commodore pact sparks talk of IBM PC-compatible micro|author=Kathy Chin|work=InfoWorld|date=March 26, 1984}}</ref>
|-
| [[Olivetti&nbsp;M24]]/[[AT&T&nbsp;6300]] / Logabax Persona 1600
| [[Olivetti]], marketed by [[AT&T]]
| | {{Date table sorting|1983}} (AT&T&nbsp;6300 June&nbsp;1984)
| 8086
| 8&nbsp;MHz (later 10&nbsp;MHz)
| 640 KB
| 360 KB (later 720&nbsp;KB)
| true IBM compatible;<ref name="CW1985">{{cite journal |title=AT&T having trouble in computer market |journal = Computerworld: The Newspaper for IT Leaders|url=https://books.google.com/books?id=WKyJOEl_vlsC&pg=RA1-PA93 |date=13 May 1985 |publisher=Computerworld |pages=93, 100 |issn=0010-4841}}</ref><ref name="CW_1987_Joins">{{cite journal |title=AT&T joins PC compatible price cut parade |journal = Computerworld: The Newspaper for IT Leaders|url=https://books.google.com/books?id=pcVsK0mWULwC&pg=PA18 |date=27 April 1987 |publisher=Computerworld |page=18 |issn=0010-4841}}</ref> optional 640x400 color graphics
|-
| [[Zenith Z-100]]
| [[Zenith Data Systems]]
| {{Date table sorting|1982|June}}
| 8088
| 4.77&nbsp;MHz
| 768 KB
| 360 KB
| optional 8 color 640x255 graphics, external 8" floppy drives<ref name=hardware>[https://books.google.com/books?id=EDAEAAAAMBAJ&dq=Zenith+Z-100+Original+Desktop+Computer&pg=PA35 Zenith challenges IBM's share of micro market], By Paul Freiberger, Page 35, [[InfoWorld]], 13 September 1982</ref>
|-
| [[HP-150]]
| [[Hewlett-Packard]]
| {{Date table sorting|1983|Nov}}
| 8088
| 8&nbsp;MHz
| 640 KB
| 270 KB (later 710&nbsp;KB)
| primitive touchscreen<ref name="HPCompMusHP150">{{cite web |title=150 Touchscreen |url= http://hpmuseum.net/display_item.php?hw=43 |department=Business Desktops/Calcs: 100 Series Selection |website=HP Computer Museum |access-date=March 18, 2018}}</ref>
|-
| [[Compaq Portable]]
| [[Compaq]]
| {{Date table sorting|1983|Jan}}
| 8088
| 4.77&nbsp;MHz
| 640 KB
| 360 KB
| sold as a true IBM compatible{{r|mace19840109_16}}<ref name="pc19840124"/><ref>{{cite web |url = http://www.islandnet.com/~kpolsson/comphist/comp1982.htm |title = Chronology of Personal Computers (1982) |access-date = 2024-09-07 |author = Ken Polsson }}</ref><ref name="pollack19830327">{{Cite news |last=Pollack |first=Andrew |url=https://www.nytimes.com/1983/03/27/business/big-ibm-has-done-it-again.html |title=Big I.B.M. Has Done It Again |date=1983-03-27 |work=The New York Times |access-date=2024-09-07 |page=Section 3, Page 1 |language=en-US |issn=0362-4331 |url-access=limited }}</ref>
|-
| [[Compaq Deskpro]]
| [[Compaq]]
| {{Date table sorting|1984}}
| 8086
| 8&nbsp;MHz
| 640 KB
| 360 KB
| sold as true IBM XT compatible<ref name=":0">{{cite web|title=Compaq Deskpro Model 1 - Computing History|url=http://www.computinghistory.org.uk/det/7793/Compaq-Deskpro-Model-1/|website=www.computinghistory.org.uk|accessdate=7 September 2024}}</ref>
|-
| [[MPC 1600]]
| [[Columbia Data Products]]
| {{Date table sorting|1982|June}}
| 8088
| 4.77&nbsp;MHz
| 640 KB
| 360 KB
| true IBM compatible, credited as first PC&nbsp;clone<ref name="sandler198306"/><ref>[https://books.google.com/books?id=14Kfbrc6cbAC&pg=PA451 Aboard the Columbia], By Bill Machrone, Page 451, Jun 1983, PC Mag</ref><ref name="byte198210">{{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=7 September 2024 | author=Advertisement | pages=83}}</ref><ref>{{cite news|url=https://www.nytimes.com/1984/03/13/science/personal-computers-rivals-stay-one-step-ahead-of-ibm-portable.html|title=PERSONAL COMPUTERS; RIVALS STAY ONE STEP AHEAD OF I.B.M. PORTABLE|work=The New York Times |date=March 13, 1984 |quote="Columbia Data Products (301-992- 3400) turns out another split-personality computer, appropriately named the Multi-Personal Computer. Using only the Intel 8088 microprocessor, it manifests its duality in an ability to run both I.B.M.-oriented software and software requiring an operating system called MP/M-86." |last1=Sandberg-Diment |first1=Erik }}</ref>
|-
| Eagle PC / 1600 series
| [[Eagle Computer]]
| {{Date table sorting|1982}}
| 8086
| 4.77&nbsp;MHz
| 640 KB
| 360 KB 
| 750×352 mono graphics, first 8086 CPU<ref>{{cite book|url=https://ia801207.us.archive.org/13/items/bitsavers_eagleCompu00Brochure_9975235/Eagle_1600_Brochure_text.pdf|author=[[Eagle Computer]]|title=Eagle 1600 Brochure|access-date=September 7, 2024}}</ref>
|-
| [[Texas Instruments Professional Computer|TI Professional Computer]]
| [[Texas Instruments]]
| {{Date table sorting|1983|Jan}}
| 8088
| 5&nbsp;MHz
| 256 KB
| 320 KB
| 720x300 color graphics<ref name=TIPCbrochure>{{cite web |url=https://classic.technology/wp-content/uploads/2014/09/texasinstrumentsprofcomputer.pdf |title=Texas Instruments Professional Computer |publisher=[[Texas Instruments]] |via=Classic Computer Brochures |year=1983 |access-date=September 7, 2024}}</ref><ref name=Byte1983>
{{cite magazine |last=Haas |first=Mark |date=December 1983 |title=The Texas Instruments Professional Computer – Daring to be somewhat different |url=https://archive.org/details/byte-magazine-1983-12/page/n287 |magazine=[[Byte (magazine)|Byte]] |location=Peterborough NH |publisher=McGraw-Hill |volume=8 |issue=12 |pages=286–324 |access-date=September 7, 2024 }}
</ref><ref name=LowEndM>{{cite web |url=https://lowendmac.com/2015/texas-instruments-personal-computers/ |title=Texas Instruments' Personal Computers |first=Daniel |last=Knight |date=December 19, 2015 |work=LowEndMac |access-date=September 7, 2024}}</ref>
|-
| [[DEC Rainbow]]
| [[Digital Equipment Corporation]]
| {{Date table sorting|1982}}
| 8088
| 4.81&nbsp;MHz
| 768 KB
| 400 KB
| 132x24 text mode, 8088 and [[Z80]] CPUs<ref name="vintage-computer">{{cite web |last=Klein |first=Erik S. |title=DEC Rainbow 100 |work=The Vintage Computer |url=http://www.vintage-computer.com/decrainbow100.shtml |accessdate=7 September 2024 |archive-url=https://web.archive.org/web/20160703113758/http://www.vintage-computer.com/decrainbow100.shtml |archive-date=3 July 2016 |url-status=dead}}</ref><ref name="Old-Computers.com">{{cite web |last=Ryan |first=Chris |title=Digital Rainbow 100 |work=Old-Computers.com |url=http://www.old-computers.com/MUSEUM/computer.asp?st=1&c=284 |accessdate=7 September 2024 |archive-url=https://web.archive.org/web/20230428184609/https://www.old-computers.com/museum/computer.asp?st=1&c=284 |archive-date=28 April 2023}}</ref>
|-
| Wang PC
| [[Wang Laboratories]]
| {{Date table sorting|1985|Aug}}
| 8086
| 8&nbsp;MHz
| 512 KB
| 360 KB
| 800x300 mono graphics<ref>{{cite web|url=https://www.seasip.info/VintagePC/wangpc.html|title=Wang Professional Computer|website=Seasip.info/VintagePC|access-date=September 7, 2024|last=Elliot|first=John|date=January 3, 2012|archive-url=https://web.archive.org/web/20140721000716/https://www.seasip.info/VintagePC/wangpc.html|archive-date=July 21, 2014}}</ref>
|-
| [[MBC-550]]
| [[Sanyo]]
| {{Date table sorting|1982}}
| 8088
| 3.6&nbsp;MHz
| 256 KB
| 360 KB (later 720&nbsp;KB)
| 640x200 8 color graphics (R, G, B bitplanes)<ref>{{cite book | date=November 1983 | url=https://archive.org/details/SanyoMBC550SeriesUsersGuideNovember1983 | title=MBC-550 Series User's Guide | publisher=Sanyo Electric | edition=Rev 1.0 | via=the Internet Archive}}</ref>
|-
| [[Apricot PC]]
| [[Apricot Computers]]
| {{Date table sorting|1983}}
| 8086
| 4.77&nbsp;MHz
| 768 KB
| 720 KB
| 800x400 mono graphics, 132x50 text mode<ref name="ocapr">{{cite web |last=Ryan |first=Chris |url=https://www.old-computers.com/museum/computer.asp?st=1&c=499 |title=Apricot PC |work=Old-Computers.com |archive-url=https://web.archive.org/web/20231106095257/https://www.old-computers.com/museum/computer.asp?st=1&c=499| archive-date=November 6, 2023| access-date=September 7, 2024}}</ref>
|-
| TS-1603
| [[TeleVideo]]
| {{Date table sorting|1983|Apr}}
| 8088
| 4.77&nbsp;MHz
| 256 KB
| 737 KB
| keyboard had palm rests, 16 function keys;<ref>{{cite web|url=https://www.computinghistory.org.uk/det/4771/TeleVideo-TS-1603-Computer-System/|access-date=September 7, 2024|title=TeleVideo TS 1603 Computer System - Computer|website=computinghistory.org.uk|publisher=The Centre for Computing History}}</ref> built-in modem
|-
| Tava PC
| [[Tava Corporation]]
| {{Date table sorting|1983|Oct}}
| 8088
| 4.77&nbsp;MHz
| 640 KB
| 360 KB
| true IBM compatible, credited as first private-label clone sold by manufacturer's stores<ref name=OReilly1984>{{cite journal | last=O'Reilly | first=Richard | date=June 28, 1994 | url=https://www.newspapers.com/clip/121790691/frustrated-by-big-guys-disinterest/ | title=Frustrated by big guys' disinterest, Perry Lamba builds his own IBM PC act-alike | journal=Southtown Star | location=Tinley Park, Illinois | page=B-7 | via=Newspapers.com}}</ref><ref name=Levy>{{cite journal | last=Levy | first=Melissa | date=December 5, 1984 | url=https://www.proquest.com/docview/211008626/ | title=Little is beautiful for Micro Express | journal=Orange County Business Journal | publisher=American City Business Journals | volume=17 | issue=49 | page=1 | via=ProQuest}}</ref><ref name=Rosch>{{cite journal | last=Rosch | first=W. L. | date=September 10, 1985 | url=https://link.gale.com/apps/doc/A648748/GPS?sid=wikipedia | title=Tava's Megaplus and Sprite Machines: PC Lookalikes Are Good Buys as 2nd Computers | journal=PC Week | volume=2 | issue=36 | page=91 | publisher=Ziff-Davis | via=Gale}}</ref><ref>{{cite journal | last=Sheerin | first=M. | date=October 17, 1983 | url=https://link.gale.com/apps/doc/A505744/GPS?sid=wikipedia | title=Compu Shack Affiliate Tava Corp. Offering PC-Compatible Micro | journal=Computer Retail News | publisher=UBM LLC | issue=30 | page=20 | via=Gale}}</ref>
|-
| [[Tandy 2000]]
| [[Tandy Corporation]]
| {{Date table sorting|1983|Sept}}
| 80186
| 8&nbsp;MHz
| 768 KB
| 720 KB
| redefinable character set,{{citation needed|date=September 2024}} optional 640x400 8-color<ref name="rsc17">{{cite web |title=1987 Radio Shack Tandy Computer Catalog RSC-17B |url=https://radioshackcatalogs.com/flipbook/c1987_rsc-17b.html |website=radioshackcatalogs dot com |publisher=Tandy/Radio Shack |pages=6,7,34 |year=1987 |archive-url=https://web.archive.org/web/20210103215510/https://radioshackcatalogs.com/flipbook/c1987_rsc-17b.html |archive-date=January 3, 2021}}</ref> or mono graphics
|}

==="Operationally Compatible"===
{{quote|The first thing to think about when considering an IBM-compatible computer is, "How compatible is it?"|''BYTE'', September 1983{{r|malloy198309}}}}

In May 1983, Future Computing defined four levels of compatibility:<ref name="ward198311">{{cite news | url=https://archive.org/stream/byte-magazine-1983-11/1983_11_BYTE_08-11_Inside_the_IBM_PC#page/n249/mode/2up | title=Levels of PC Compatibility | work=BYTE | date=November 1983 | access-date=March 19, 2016 | author=Ward, Ronnie | pages=248–249}}</ref>

* ''Operationally Compatible''. Can run "the top selling" IBM PC software, use PC expansion boards, and read and write PC disks. Has "complementary features" like portability or lower price that distinguish computer from the PC, which is sold in the same store. Examples: (Best) Columbia Data Products, Compaq; (Better) Corona; (Good) Eagle.
* ''Functionally Compatible''. Runs own version of popular PC software. Cannot use PC expansion boards but can read and write PC disks. Cannot become Operationally Compatible. Example: [[Texas Instruments Professional Computer and Professional Portable Computer|TI Professional]].
* ''Data Compatible''. May not run top PC software. Can read and/or write PC disks. Can become Functionally Compatible. Examples: NCR Decision Mate, [[Olivetti M20]], Wang PC, [[Zenith Z-100]].
* ''Incompatible''. Cannot read PC disks. Can become Data Compatible. Examples: [[Altos 586]], [[Rainbow 100|DEC Rainbow 100]], [[Grid Compass]], [[Victor 9000]].

[[File:Compaq mddos ver1-12.jpg|thumb|right|MS-DOS version 1.12 for Compaq Personal Computers]]

During development, Compaq engineers found that ''[[Microsoft Flight Simulator]]'' would not run because of what [[subLOGIC]]'s [[Bruce Artwick]] described as "a bug in one of Intel's chips", forcing them to make their new computer [[bug compatibility|bug compatible]] with the IBM PC.{{r|yakal198501}} At first, few clones other than Compaq's offered truly full compatibility.<ref name="alsop19940131">{{cite magazine |url=https://books.google.com/books?id=AzsEAAAAMBAJ&pg=PT1 | title=A public Windows pane to make compatibility clearer | access-date=February 28, 2011 | author=Alsop, Stewart | date=January 31, 1994 | magazine=InfoWorld | pages=102}}</ref> [[Jerry Pournelle]] purchased an IBM PC in mid-1983, "[[Model F keyboard|rotten keyboard]] and all", because he had "four cubic feet of unevaluated software, much of which won't run on anything but an IBM PC. Although a lot of machines claim to be 100 percent IBM PC compatible, I've yet to have one arrive ... Alas, a lot of stuff doesn't run with Eagle, Z-100, [[Compupro]], or anything else we have around here".<ref name="pournelle198309">{{Cite magazine |last=Pournelle |first=Jerry |author-link=Jerry Pournelle |date=September 1983 |title=Eagles, Text Editors, New Compilers, and Much More |url=https://archive.org/details/byte-magazine-1983-09 |magazine=BYTE |page=[https://archive.org/details/byte-magazine-1983-09/page/n322 307] |access-date=April 7, 2019}}</ref> Columbia Data Products's November 1983 sales brochure stated that during tests with retail-purchased computers in October 1983, its own and Compaq's products were compatible with all tested PC software, while Corona and Eagle's were less compatible.<ref name="cdp198311">{{Cite book |url=https://archive.org/details/1983-columbia-eval/mode/1up |title=IBM PC Compatibles Competitive Evaluation |year=1983 |publisher=Columbia Data Products |publication-date=November 1983 |access-date=October 15, 2022}}</ref> [[Columbia University]] reported in January 1984 that [[Kermit (protocol)|Kermit]] ran without modification on Compaq and Columbia Data Products clones, but not on those from Eagle or Seequa. Other MS-DOS computers also required custom code.<ref name="dacruz19840123">{{Cite mailing list |last=da Cruz |first=Frank |title=IBM PC Kermit |mailing-list=Info-Kermit Digest |date=January 23, 1984 |url=https://www.columbia.edu/kermit/ftp/e/mail.84a |access-date=2024-10-12 |publisher=Kermit Project, Columbia University}}</ref>

By December 1983 Future Computing stated that companies like Compaq, Columbia Data Products, and Corona that emphasized IBM PC compatibility had been successful, while non-compatible computers had hurt the reputations of others like TI and DEC despite superior technology. At a San Francisco meeting it warned 200 attendees, from many American and foreign computer companies as well as IBM itself, to "Jump on the IBM PC-compatible bandwagon—quickly, and as compatibly as possible".<ref name="sandler198312">{{Cite magazine |last=Sandler |first=Corey |date=December 1983 |title=The Prognosticators Pronounce: Future Compilations On The PC |url=https://books.google.com/books?id=05wAGZQlo9QC&pg=PA248 |magazine=PC Magazine |pages=248–256 |access-date=2023-12-27}}</ref> Future Computing said in February 1984 that some computers were "press-release compatible", exaggerating their actual compatibility with the IBM PC.<ref name="salisbury19840209">{{Cite news |last=Salisbury |first=David F. |date=February 9, 1984 |title=Why the IBM PC spawned a mob of look-alikes |work=The Christian Science Monitor|url=https://www.csmonitor.com/1984/0209/020908.html |access-date=October 7, 2020 |issn=0882-7729}}</ref> Many companies were reluctant to have their products' PC compatibility tested. When ''PC Magazine'' requested samples from computer manufacturers that claimed to produce compatibles for an April 1984 review, 14 of 31 declined.<ref name="krasnoff19840320">{{cite news |url=https://books.google.com/books?id=1tFFnOMCvv4C&pg=PA57 | title=No Matter Who's Invited, Some Will Turn Out To Be Incompatible | work=PC Magazine | date=March 20, 1984 | access-date=October 24, 2013 | author=Krasnoff, Barbara | pages=57}}</ref><ref name="krasnoff19840403">{{cite news |url=https://books.google.com/books?id=e-gI2W-3JwkC&pg=PA110 | title=Putting PC Compatibles To the Test | work=PC Magazine | date=April 3, 1984 | access-date=October 24, 2013 | author=Krasnoff, Barbara | pages=110–144}}</ref> Corona specified that "Our systems run all software that conforms to IBM PC programming standards. And the most popular software does."<ref name="corona19840227">{{cite news | url=https://books.google.com/books?id=gy4EAAAAMBAJ&pg=PA41 | title=Pick Up Where IBM Leaves Off. | work=InfoWorld | date=February 27, 1984 | access-date=January 18, 2015 | pages=41 | type=advertisement}}</ref> When a ''[[BYTE]]'' journalist asked to test [[Peachtext]] at the Spring 1983 [[COMDEX]], Corona representatives "hemmed and hawed a bit, but they finally led me ... off in the corner where no one would see it should it fail". The magazine reported that "Their hesitancy was unnecessary. The disk booted up without a problem".<ref name="malloy198309">{{cite news | url=https://archive.org/stream/byte-magazine-1983-09/1983_09_BYTE_08-09_Portable_Computers_in_Depth#page/n235/mode/2up | title=The Corona Portable PC | work=BYTE | date=September 1983 | access-date=August 16, 2015 | author=Malloy, Rich | pages=226–228}}</ref> [[Zenith Data Systems]] was bolder, bragging that its Z-150 ran all applications people brought to test with at the 1984 [[West Coast Computer Faire]].{{r|pournelle198407}}

''[[Creative Computing]]'' in 1985 stated, "we reiterate our standard line regarding the IBM PC compatibles: try the package you want to use before you buy the computer."{{r|lockwood198509}} Companies modified their computers' BIOS to work with newly discovered incompatible applications,<ref name="pournelle198411">{{cite news |url=https://archive.org/stream/byte-magazine-1984-11/1984_11_BYTE_09-12_New_Chips#page/n359/mode/2up | title=NCC Reflections | work=BYTE | date=November 1984 | access-date=October 23, 2013 | author=Pournelle, Jerry | pages=361}}</ref> and reviewers and users developed [[Stress testing (software)|stress tests]] to measure compatibility; by 1984 the ability to operate Lotus 1-2-3 and ''Flight Simulator'' became the standard,<ref name="mace19840109_16">{{cite news | url=https://books.google.com/books?id=ey4EAAAAMBAJ&pg=PA79 | title=IBM PC clone makers shun total compatibility | work=InfoWorld | date=January 9–16, 1984 | access-date=February 4, 2015 | author=Mace, Scott | pages=79–81}}</ref><ref name="poor19841002">{{cite news |url=https://books.google.com/books?id=d-tPdHcBE9wC&pg=PA206 | title=Zenith Strikes Twice | work=PC Magazine | date=October 2, 1984 | access-date=October 25, 2013 | author=Poor, Alfred | pages=206}}</ref>{{r|pournelle198411}}<ref name="callamaras198411">{{cite news |url=https://archive.org/stream/byte-magazine-1984-11/1984_11_BYTE_09-12_New_Chips#page/n273/mode/2up | title=The Columbia Multipersonal Computer-VP | work=BYTE | date=November 1984 | access-date=October 23, 2013 | author=Callamaras, Peter V. | pages=276}}</ref><ref name="lockwood198509">{{cite news |url=http://www.atarimagazines.com/creative/v11n9/50_Zenith_Z151_choice_of_U.php | title=Zenith Z-151; choice of U.S. Air Force and Navy | work=Creative Computing | date=September 1985 | access-date=February 26, 2013 | author=Lockwood, Russ | pages=50}}</ref><ref name="mace19860505">{{cite magazine |url=https://books.google.com/books?id=Qi8EAAAAMBAJ&q=%22flight+simulator%22&pg=PA5 | title=Amiga, Atari Ready PC Emulators | access-date=February 28, 2011 |author1=Mace, Scott |author2=Karen Sorensen | date=May 5, 1986 | magazine=InfoWorld | pages=5}}</ref> with compatibles specifically designed to run them<ref name="pournelle198407">{{Cite magazine |last=Pournelle, Jerry |author-link=Jerry Pournelle |date=July 1984 |title=The West Coast Faire |url=http://blog.modernmechanix.com/the-west-coast-faire/ |magazine=[[Byte (magazine)|Byte]] |page=136 |access-date=November 8, 2011 |archive-date=May 28, 2012 |archive-url=https://web.archive.org/web/20120528184149/http://blog.modernmechanix.com/the-west-coast-faire/ |url-status=dead }}</ref><ref name="yakal198501">{{cite news | url=https://archive.org/stream/1985-01-computegazette/Compute_Gazette_Issue_19_1985_Jan#page/n33/mode/2up | title=Bruce Artwick / The Designer Behind Flight Simulator II | work=Compute!'s Gazette | date=January 1985 | access-date=July 6, 2014 | author=Yakal, Kathy | pages=32}}</ref> and prominently advertising their compatibility.<ref name="trivette198504">{{cite news |url=http://www.atarimagazines.com/compute/issue59/review_lotus_123.php |title=Lotus 1-2-3 For IBM PCjr |work=[[Compute!]] |date=April 1985 |access-date=2013-10-06 |author-last=Trivette |author-first=Donald B. |pages=63}}</ref>

IBM believed that some companies such as Eagle, Corona, and Handwell infringed on its copyright, and after ''[[Apple Computer, Inc. v. Franklin Computer Corp.]]'' successfully forced the clone makers to stop using the BIOS. The [[Phoenix Technologies|Phoenix BIOS]] in 1984, however, and similar products such as [[American Megatrends|AMI BIOS]], permitted computer makers to legally build essentially 100%-compatible clones without having to reverse-engineer the PC BIOS themselves.<ref name="caruso19840227">{{cite news | url=https://books.google.com/books?id=gy4EAAAAMBAJ&pg=PA15 | title=IBM wins disputes over PC copyrights | work=InfoWorld | date=February 27, 1984 | access-date=January 18, 2015 | author=Caruso, Denise | pages=15}}</ref><ref name="langdell19840710">{{cite news | url=https://books.google.com/books?id=Bwng8NJ5fesC&pg=PA56 | title=Phoenix Says Its BIOS May Foil IBM's Lawsuits | work=PC Magazine | date=July 10, 1984 | access-date=October 25, 2013 | author=Langdell, James | pages=56}}</ref><ref name="schmidt199407">{{cite news|url=http://www.smartcomputing.com/editorial/article.asp?article=articles%2F1994%2Fjuly94%2Fpcn0713%2Fpcn0713.asp |title=What Is The BIOS? |work=Computing Basics |date=July 1994 |author=Schmidt, Robert | access-date=September 19, 2011 | archive-url=https://web.archive.org/web/20120310002756/http://www.smartcomputing.com/editorial/article.asp?article=articles%2F1994%2Fjuly94%2Fpcn0713%2Fpcn0713.asp | archive-date=March 10, 2012}}</ref> A September 1985 ''[[InfoWorld]]'' chart listed seven compatibles with {{val|256|u=KB}} RAM, two disk drives, and monochrome monitors for {{US$|long=no|1495}} to {{US$|long=no|2320}}, while the equivalent IBM PC cost {{US$|long=no|2820}}.<ref name="iw19850930">{{cite news | url=https://books.google.com/books?id=iS8EAAAAMBAJ&pg=PA1 | title=Competing on Price | work=InfoWorld | date=September 30, 1985 | access-date=February 20, 2015 | pages=1}}</ref> The Zenith Z-150{{r|poor19841002}} and inexpensive [[Leading Edge Model D]] are even compatible with IBM proprietary diagnostic software, unlike the Compaq Portable.<ref name="freeze19851216">{{cite news | url=https://books.google.com/books?id=cC8EAAAAMBAJ&pg=PA43 | title=Leading Edge: Superior Value in IBM-PC Clone Market Contest | work=InfoWorld | date=December 16, 1985 | access-date=July 22, 2014 | author=Freeze, Ken | pages=43}}</ref> By 1986 ''[[Compute!]]'' stated that "clones are generally reliable and about 99 percent compatible",<ref name="halfhill198612">{{cite news | url=https://archive.org/stream/1986-12-compute-magazine/Compute_Issue_079_1986_Dec#page/n33/mode/2up | title=The MS-DOS Invasion / IBM Compatibles Are Coming Home | work=Compute! | date=December 1986 | access-date=November 9, 2013 | author=Halfhill, Tom R. |page=32}}</ref> and a 1987 survey in the magazine of the clone industry did not mention software compatibility, stating that "PC by now has come to stand for a computer capable of running programs that are managed by MS-DOS".<ref name=ferrell198707>{{Cite magazine |last=Ferrell |first=Keith |date=July 1987 |title=IBM Compatibles: The Universe Expands |url=https://www.atarimagazines.com/compute/issue86/007_1_IBM_Compatibles.php |magazine=Compute! |page=14 |access-date=January 31, 2020}}</ref>

==The decreasing influence of IBM==
{{quote|The main reason why an IBM standard is not worrying is that it can help competition to flourish. IBM will soon be as much a prisoner of its standards as its competitors are. Once enough IBM machines have been bought, IBM cannot make sudden changes in their basic design; what might be useful for shedding competitors would shake off even more customers.|''The Economist'', November 1983{{r|economist19831126}}}}
[[File:PowerPak 286 running AutoCAD on MS-DOS (1987).jpg|thumb|The PowerPak [[Intel 80286|286]], an IBM PC compatible computer running [[AutoCAD]] under [[MS-DOS]]]]
[[File:DeskPro 386S.jpg|thumb|IBM PC compatible computer with processor [[i386|Intel&nbsp;80386]]]]
[[File:MikroMikko 4 TT m216 Tekniikan museo 01.jpg|thumb|IBM PC compatible computer with processor [[i486|Intel&nbsp;80486]]]]
[[File:Ibm300pl.jpg|thumb|IBM 300 PL computer with processor Intel [[Pentium (original)|Pentium&nbsp;I]] and [[Windows 95]]]]
[[File:Dell Desktop Computer in school classroom.jpg|thumb|[[Dell]] OptiPlex with processor Intel [[Pentium&nbsp;4]]]]
In February 1984 ''Byte'' wrote that "IBM's burgeoning influence in the PC community is stifling innovation because so many other companies are mimicking Big Blue",<ref name="curran198402">{{cite magazine | url=https://archive.org/stream/byte-magazine-1984-02/1984_02_BYTE_09-02_Benchmarks#page/n5/mode/2up | title=The Compatibility Craze |magazine=BYTE | date=Feb 1984 | access-date=August 26, 2015 | author=Curran, Lawrence J. |page=4}}</ref> but ''[[The Economist]]'' stated in November 1983, "The main reason why an IBM standard is not worrying is that it can help competition to flourish".<ref name="economist19831126">{{Cite magazine |date=November 26, 1983 |title=Can Anybody Tackle IBM? |url=https://books.google.com/books?id=UCIvSU6Y2GAC&pg=PA125 |magazine=The Economist}}</ref>

By 1983, IBM had about 25% of sales of personal computers between {{US$|long=no|1000}} and {{US$|long=no|10000}}, and computers with some PC compatibility were another 25%.{{r|salisbury19840209}} As the market and competition grew IBM's influence diminished. Writing that even "IBM has to continue to be IBM compatible", in November 1985 ''PC Magazine'' stated "Now that it has created the [PC] market, the market doesn't necessarily need IBM for the machines. It may depend on IBM to set standards and to develop higher-performance machines, but IBM had better conform to existing standards so as to not hurt users".<ref name="machrone19851126">{{cite news |url=https://books.google.com/books?id=VUKL2rKYb8UC&pg=PA59 | title=Compatibility Wars—Here and Abroad | work=PC Magazine | date=November 26, 1985 | access-date=October 29, 2013 | author=Machrone, Bill | pages=59}}</ref> Observers noted IBM's silence when the industry that year quickly adopted the [[expanded memory]] standard, created by Lotus and Intel without IBM's participation.<ref name="maremaa19850617">{{Cite magazine |last=Maremaa |first=Tom |date=1985-06-17 |title=Board Makers Flock to New Standard |url=https://books.google.com/books?id=FS8EAAAAMBAJ&pg=PA30 |access-date=2025-05-01 |magazine=InfoWorld |pages=30–34 |volume=7 |issue=24}}</ref> In January 1987, [[Bruce Webster]] wrote in ''Byte'' of rumors that IBM would introduce proprietary personal computers with [[OS/2|a proprietary operating system]]: "Who cares? If IBM does it, they will most likely just isolate themselves from the largest marketplace, in which they really can't compete anymore anyway". He predicted that in 1987 the market "will complete its transition from an IBM standard to an Intel/MS-DOS/expansion bus standard ... Folks aren't so much concerned about IBM compatibility as they are about Lotus 1-2-3 compatibility".<ref name="webster198701">{{cite news |url=https://archive.org/stream/byte-magazine-1987-01/1987_01_BYTE_12-01_Programmable_Hardware#page/n391/mode/2up | title=View and Reviews | work=[[Byte (magazine)|Byte]] | date=January 1987 | access-date=November 4, 2013 | author=Webster, Bruce | pages=367}}</ref> By 1992, ''[[Macworld]]'' stated that because of clones, "IBM lost control of its own market and became a minor player with its own technology".<ref name="borrell199205">{{Cite magazine |last=Borrell |first=Jerry |date=May 1992 |title=Opening Pandora's Box |url=https://archive.org/stream/MacWorld_9205_May_1992#page/n21/mode/2up |magazine=Macworld |pages=21–22}}</ref>

''The Economist'' predicted in 1983 that "IBM will soon be as much a prisoner of its standards as its competitors are", because "Once enough IBM machines have been bought, IBM cannot make sudden changes in their basic design; what might be useful for shedding competitors would shake off even more customers".{{r|economist19831126}} After the [[Compaq Deskpro 386]] became the first 80386-based PC, ''PC'' wrote that owners of the new computer did not need to fear that future IBM products would be incompatible with the Compaq, because such changes would also affect millions of real IBM PCs: "In sticking it to the competition, IBM would be doing the same to its own people".<ref name="howard19861125">{{Cite magazine |last=Howard |first=Bill |date=1986-11-25 |title=386 Compatibility: What, Me Worry? |url=https://books.google.com/books?id=UwLE_FWJ-_0C&pg=PA141 |access-date=2024-11-01 |magazine=PC |page=141}}</ref> After IBM announced the [[OS/2]]-oriented PS/2 line in early 1987, sales of existing DOS-compatible PC compatibles rose, in part because the proprietary operating system was not available.<ref name="parker19870504">{{Cite magazine |last=Parker |first=Rachel |date=May 4, 1987 |title=PC Vendors' Sales Rise Following PS/2 Debut |url=https://books.google.com/books?id=zzwEAAAAMBAJ&pg=PA3 |magazine=InfoWorld |pages=1, 85}}</ref> In 1988, [[Gartner Group]] estimated that the public purchased 1.5 clones for every IBM PC.<ref name="scisco198812">{{cite news | url=https://archive.org/stream/1988-12-compute-magazine/Compute_Issue_103_1988_Dec#page/n11/mode/2up | title=Bus, Bus, Magic Bus | work=Compute! | date=December 1988 | access-date=November 10, 2013 | author=Scisco, Peter | pages=10}}</ref> By 1989 Compaq was so influential that industry executives spoke of "Compaq compatible", with observers stating that customers saw the company as IBM's equal<ref name="iw19890123">{{cite news | url=https://books.google.com/books?id=KzoEAAAAMBAJ&pg=PP1 | title=Compaq Vying To Become the IBM of the '90s | work=InfoWorld | date=January 23, 1989 | access-date=March 17, 2016 |author1=LaPlante, Alice |author2=Furger, Roberta | pages=1, 8}}</ref> or superior.{{r|lewis19891022}} A 1990 [[American Institute of Certified Public Accountants]] member survey found that 23% of respondents used IBM computer hardware, and 16% used Compaq.<ref name="aicpa1990">{{Cite report |url=https://egrove.olemiss.edu/cgi/viewcontent.cgi?article=1563&context=aicpa_guides |title=1990 AICPA survey of computer usage |author-link=American Institute of Certified Public Accountants |year=1990 |id=561 |access-date=2025-04-30}}</ref>

After 1987, IBM PC compatibles dominated both the home and business markets of commodity computers,<ref name="Reimer">{{cite web|url=https://arstechnica.com/articles/culture/total-share.ars/4|title=Total share: 30 years of personal computer market share figures|last=Reimer|first=Jeremy |website=Ars Technica|date=December 15, 2005|access-date=September 13, 2008}}</ref> with other notable alternative architectures being used in niche markets, like the [[Macintosh]] computers offered by [[Apple Inc.]] and used mainly for [[desktop publishing]] at the time, the aging 8-bit [[Commodore 64]] which was selling for $150 by this time and became the world's bestselling computer, the 32-bit [[Amiga|Commodore Amiga]] line used for [[television]] and [[video production]] and the 32-bit [[Atari ST]] used by the music industry. However, IBM itself lost the main role in the market for IBM PC compatibles by 1990. A few events in retrospect are important:

* IBM designed the PC with an [[open architecture]] which permitted clone makers to use freely available non-proprietary components.<ref>{{cite web|last1=Miller|first1=Michael|title=Why The IBM PC Had An Open Architecture|url=http://forwardthinking.pcmag.com/pc-hardware/286065-why-the-ibm-pc-had-an-open-architecture|website=forwardthinking dot pcmag dot com|publisher=Ziff Davis|access-date=June 27, 2017}}</ref>
* Microsoft included a clause in its contract with IBM which permitted the sale of the finished PC operating system ([[PC DOS]]) to other computer manufacturers. These IBM competitors licensed it, as [[MS-DOS]], in order to offer PC compatibility for less cost.<ref>{{cite web|last1=Brown|first1=Marcel|title=IBM Signs A Deal With The Devil|url=http://thisdayintechhistory.com/11/06/ibm-signs-a-deal-with-the-devil/|website=thisdayintechhistory dot com|publisher=MB Tech, Inc.|access-date=June 27, 2017}}</ref>
* The 1982 introduction of the [[Columbia Data Products]] MPC 1600, the first 100% IBM PC compatible computer.
* The 1983 introduction of the [[Compaq Portable]], providing portability unavailable from IBM at the time.
* An Independent Business Unit (IBU) within IBM developed the IBM PC and XT. IBUs did not share in corporate [[research and development|R&D]] expense. After the IBU became the Entry Systems Division it lost this benefit, greatly decreasing margins.<ref name="killen1984fall">{{cite news | url=https://archive.org/stream/byte-magazine-1984-09/1984_09_BYTE_09-09_Guide_to_the_IBM_PCs#page/n33/mode/2up | title=IBM Forecast / Market Dominance | work=[[Byte (magazine)|Byte]] | date=Fall 1984 | access-date=March 18, 2016 | author=Killen, Michael | pages=30–38}}</ref>
* The availability by 1986 of sub-{{US$|long=no|1000}} "Turbo XT" [[PC XT]] compatibles, including early offerings from [[Dell|Dell Computer]], reducing demand for IBM's models.<ref>{{cite book|url=https://books.google.com/books?id=Vi8EAAAAMBAJ&pg=PA33|title=InfoWorld July 1986 ad: "Career Starter Kit: Everything you need to begin serious computing immediately"|date=July 7, 1986}}</ref><ref>{{cite book|url=https://books.google.com/books?id=Vy8EAAAAMBAJ&pg=PA54|title=InfoWorld July 1986|date=July 28, 1986}}</ref> It was possible to buy two of these "generic" systems for less than the cost of one IBM-branded [[PC AT]], and many companies did just that.
* By integrating more peripherals into the computer itself, compatibles like the Model D have more free [[Industry Standard Architecture|ISA]] slots than the PC.{{r|freeze19851216}}
* Compaq was the first to release an [[Intel 80386]]-based computer, almost a year before IBM,<ref name="lewis19891022">{{Cite news |last=Lewis |first=Peter H. |date=October 22, 1989 |title=THE EXECUTIVE COMPUTER; The Race to Market a 486 Machine |language=en-US |work=The New York Times |url=https://www.nytimes.com/1989/10/22/business/the-executive-computer-the-race-to-market-a-486-machine.html |access-date=May 20, 2020 |issn=0362-4331}}</ref> with the [[Compaq Deskpro 386]]. [[Bill Gates]] later said that it was "the first time people started to get a sense that it wasn't just IBM setting the standards".<ref name="millergates19970325">{{Cite interview |last=Gates |first=Bill |interviewer=Michael J. Miller |title=Interview: Bill Gates, Microsoft |url=https://books.google.com/books?id=wVDB2C8IJRYC&pg=PA230 |date=March 25, 1997 |pages=230-235}}</ref>
* IBM's 1987 introduction of the incompatible and proprietary [[MicroChannel Architecture]] (MCA) [[bus (computing)|computer bus]], for its [[IBM Personal System/2|Personal System/2]] (PS/2) line.{{r|scisco198812}}
* The split of the IBM-Microsoft partnership in development of [[OS/2]]. Tensions caused by the market success of [[Windows 3.0]] [[OS/2#1990: Breakup|ruptured the joint effort]] because IBM was committed to the 286's protected mode, which stunted OS/2's technical potential. Windows could take full advantage of the modern and increasingly affordable 386 / 386SX architecture. As well, there were cultural differences between the partners, and Windows was often bundled with new computers while OS/2 was only available for extra cost. The split left IBM the sole steward of OS/2 and it failed to keep pace with Windows.
* The 1988 introduction by the "Gang of Nine" companies of a rival bus, [[Extended Industry Standard Architecture]], intended to compete with, rather than copy, MCA.{{r|scisco198812}}
* The duelling expanded memory (EMS){{r|maremaa19850617}} and [[extended memory]] (XMS) standards of the late 1980s, both developed without input from IBM.

Despite popularity of its [[ThinkPad]] set of laptop PC's, IBM finally relinquished its role as a consumer PC manufacturer during April 2005, when it [[Acquisition of the IBM PC business by Lenovo|sold its laptop and desktop PC divisions]] ([[ThinkPad]]/[[ThinkCentre]]) to [[Lenovo]] for {{US$|1.75 billion}}.

As of October 2007, [[Hewlett-Packard]] and [[Dell]] had the largest shares of the PC market in North America. They were also successful overseas, with [[Acer Inc.|Acer]], [[Lenovo]], and [[Toshiba]] also notable. Worldwide, a huge number of PCs are "[[White box (computer hardware)|white box]]" systems assembled by myriad local systems builders. Despite advances of computer technology, the IBM PC compatibles remained 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 [[computer system|system]] [[booting|boot]]. It was often more practical to run old software on a modern system using an [[emulator]] rather than relying on these features.

In 2014 Lenovo acquired IBM's x86-based server ([[IBM System x|System x]]) business for {{US$|2.1 billion}}.

==Expandability==
One of the strengths of the PC-compatible design is its modular hardware design. End-users could readily upgrade peripherals and, to some degree, processor and memory without modifying the computer's [[motherboard]] or replacing the whole computer, as was the case with many of the [[microcomputer]]s of the time. However, as processor speed and memory width increased, the limits of the original XT/AT bus design were soon reached, particularly when driving graphics video cards. IBM did introduce an upgraded bus in the [[IBM Personal System/2|IBM PS/2]] computer that overcame many of the technical limits of the XT/AT bus, but this was rarely used as the basis for IBM-compatible computers since it required license payments to IBM both for the PS/2 bus and any prior AT-bus designs produced by the company seeking a license. This was unpopular with hardware manufacturers and several competing bus standards were developed by consortiums, with more agreeable license terms. Various attempts to standardize the interfaces were made, but in practice, many of these attempts were either flawed or ignored. Even so, there were many expansion options, and despite the confusion of its users, the PC compatible design advanced much faster than other competing designs of the time, even if only because of its market dominance.

=="IBM PC compatible" becomes "Wintel"==
During the 1990s, IBM's influence on PC architecture started to decline. "IBM PC compatible" becomes "Standard PC" in 1990s, and later "[[Advanced Configuration and Power Interface|ACPI]] PC" in 2000s. An IBM-brand PC became the exception rather than the rule. Instead of placing importance on compatibility with the IBM PC, vendors began to emphasize compatibility with [[Microsoft Windows|Windows]]. In 1993, a version of [[Windows NT]] was released that could operate on processors other than the [[x86]] set. While it required that applications be recompiled, which most developers did not do, its hardware independence was used for [[Silicon Graphics]] (SGI) x86 workstations–thanks to NT's [[Hardware abstraction layer]] (HAL), they could operate NT (and its vast application library){{Clarify|date=August 2011}}.

No mass-market personal computer hardware vendor dared to be incompatible with the latest version of Windows, and Microsoft's annual [[Windows Hardware Engineering Conference|WinHEC]] conferences provided a setting in which Microsoft could lobby for—and in some cases dictate—the pace and direction of the hardware of the PC industry. Microsoft and Intel had become so important to the ongoing development of PC hardware that industry writers began using the word [[Wintel]] to refer to the combined hardware-software system.

This terminology itself is becoming a misnomer, as Intel has lost absolute control over the direction of x86 hardware development with [[Advanced Micro Devices|AMD]]'s [[x86-64|AMD64]]. Additionally, non-Windows operating systems like [[macOS]] and [[Linux]] have established a presence on the x86 architecture.

==Design limitations and more compatibility issues==
Although the IBM PC was designed for expandability, the designers could not anticipate the hardware developments of the 1980s, nor the size of the industry they would engender. To make things worse, IBM's choice of the [[Intel 8088]] for the CPU introduced several limitations for developing software for the PC compatible platform. For example, the 8088 processor only had a 20-bit memory [[address space|addressing space]]. To expand ''PC''s beyond one megabyte, Lotus, Intel, and Microsoft jointly created [[expanded memory]] (EMS), a bank-switching scheme to allow more memory provided by add-in hardware, and accessed by a set of four 16-[[kilobyte]] "windows" inside the 20-bit addressing. Later, Intel CPUs had larger address spaces and could directly address 16 MB (80286) or more, causing Microsoft to develop [[extended memory]] (XMS) which did not require additional hardware.

"Expanded" and "extended" memory have incompatible interfaces, so anyone writing software that used more than one megabyte had to provide for both systems for the greatest compatibility until MS-DOS began including EMM386, which simulated EMS memory using XMS memory. A [[protected mode]] OS can also be written for the 80286, but DOS application compatibility was more difficult than expected, not only because most DOS applications accessed the hardware directly, bypassing BIOS routines intended to ensure compatibility, but also that most BIOS requests were made by the first 32 interrupt vectors, which were marked as "reserved" for protected mode processor exceptions by Intel.

[[Video card]]s suffered from their own incompatibilities. There was no standard interface for using higher-resolution [[SVGA]] graphics modes supported by later video cards. Each manufacturer developed their own methods of accessing the screen memory, including different mode numberings and different [[bank switching]] arrangements. The latter were used to address large images within a single 64 KB segment of memory. Previously, the VGA standard had used [[Planar (computer graphics)|planar]] video memory arrangements to the same effect, but this did not easily extend to the greater color depths and higher resolutions offered by SVGA adapters. An attempt at creating a standard named [[VESA BIOS Extensions]] (VBE) was made, but not all manufacturers used it.

When the 386 was introduced, again a [[protected mode]] OS could be written for it. This time, DOS compatibility was much easier because of [[virtual 8086 mode]]. Unfortunately programs could not switch directly between them, so eventually, some new memory-model APIs were developed, [[VCPI]] and [[DOS Protected Mode Interface|DPMI]], the latter becoming the most popular.

Because of the great number of third-party adapters and no standard for them, programming the PC could be difficult. Professional developers would operate a large test-suite of various known-to-be-popular hardware combinations.

To give consumers some idea of what sort of PC they would need to operate their software, the [[Multimedia PC]] (MPC) standard was set during 1990. A PC that met the minimum MPC standard could be marketed with the MPC logo, giving consumers an easy-to-understand specification to look for. Software that could operate on the most minimally MPC-compliant PC would be guaranteed{{who|date=April 2014}} to operate on any MPC. The MPC level 2 and MPC level 3 standards were set later, but the term "MPC compliant" never became popular. After MPC level 3 during 1996, no further MPC standards were established.

==Challenges to Wintel domination==
{| class="wikitable floatright"
|+New shipments of personal computer operating systems (000s of units)<ref>https://business.columbia.edu/sites/default/files-efs/imce-uploads/CITI/Articles/978-1-4615-5483-7_10.pdf {{Bare URL PDF|date=May 2025}}</ref>
!Operating system (vendor)
!1990
!1992
|-
|'''[[MS-DOS]] ([[Microsoft]])'''
|'''11,648'''
'''(of which 490 with Windows)'''
|'''18,525'''
'''(of which 11,056 with Windows)'''
|-
|'''[[PC DOS]] ([[IBM]])'''
|'''3,031'''
|'''2,315'''
|-
|'''[[DR DOS]] ([[Digital Research]]/[[Novell]])'''
|'''1,737'''
|'''1,617'''
|-
|[[Classic Mac OS|Macintosh System]] ([[Apple Inc.|Apple]])
|1,411
|2,570
|-
|[[Unix]] (various)
|357
|797
|-
|[[OS/2]] (IBM/Microsoft)
|0
|409
|-
|Others ([[NEC]], [[Commodore International|Commodore]] etc.)
|5,079
|4,458
|}
By the late 1990s, the success of [[Microsoft Windows]] had driven rival commercial [[operating system]]s into near-extinction, and had ensured that the "IBM PC compatible" computer was the dominant [[computing platform]]. This meant that if a developer made their software only for the [[Wintel]] platform, they would still be able to reach the vast majority of computer users. The only major competitor to Windows with more than a few percentage points of [[market share]] was [[Apple Inc.]]'s [[Macintosh]]. The Mac started out billed as "the computer for the rest of us", but high prices and closed architecture drove the Macintosh into an education and [[desktop publishing]] niche, from which it only emerged in the mid-2000s. By the mid-1990s the Mac's market share had dwindled to around 5% and introducing a new rival operating system had become too risky a commercial venture. Experience had shown that even if an operating system was technically superior to Windows, it would be a failure in the market ([[BeOS]] and [[OS/2]] for example). In 1989, [[Steve Jobs]] said of his new [[NeXT]] system, "It will either be the last new hardware platform to succeed, or the first to fail."{{Citation needed|date=April 2018}} Four years later in 1993, NeXT announced it was ending production of the [[NeXTcube]] and porting [[NeXTSTEP]] to Intel processors.

Very early on in PC history, some companies introduced their own XT-compatible [[chipset]]s. For example, [[Chips and Technologies]] introduced their [[NEAT chipset|82C100]] XT Controller which integrated and replaced six of the original XT circuits: one [[Intel 8237|8237]] DMA controller, one [[Intel 8253|8253]] interrupt timer, one [[Intel 8255|8255]] parallel interface controller, one [[Intel 8259|8259]] interrupt controller, one [[Intel 8284|8284]] clock generator, and one [[Intel 8288|8288]] bus controller. Similar non-Intel chipsets appeared for the AT-compatibles, for example OPTi's 82C206 or 82C495XLC which were found in many 486 and early Pentium systems.<ref name="Tooley2013">{{cite book|author=Mike Tooley|title=PC Based Instrumentation and Control|url=https://books.google.com/books?id=A__U9Kh5C-4C&pg=PA32|year=2005|publisher=Newness|edition=3rd|isbn=978-1-136-37449-4|page=32}}</ref> The x86 chipset market was very volatile though. In 1993, [[VLSI Technology]] had become the dominant market player only to be virtually wiped out by Intel a year later. Intel has been the uncontested leader ever since.<ref name="Mueller2011">{{cite book|author=Scott M. Mueller|title=Upgrading and Repairing PCs|year=2011|publisher=Que Publishing|isbn=978-0-13-268218-3|edition=20th|page=171}}</ref> As the "Wintel" platform gained dominance Intel gradually abandoned the practice of licensing its technologies to other chipset makers; in 2010 Intel was involved in litigation related to their refusal to license their processor bus and related technologies to other companies like [[Nvidia]].<ref>[http://news.cnet.com/8301-13924_3-20010399-64.html Intel vs. Nvidia: The tech behind the legal case]</ref>

Companies such as [[AMD]] and [[Cyrix]] developed alternative x86 CPUs that were functionally compatible with Intel's. Towards the end of the 1990s, AMD was taking an increasing share of the CPU market for PCs. AMD even ended up playing a significant role in directing the development of the x86 platform when its Athlon line of processors continued to develop the classic x86 architecture as Intel deviated with its [[NetBurst]] architecture for the Pentium 4 CPUs and the [[IA-64]] architecture for the [[Itanium]] set of server CPUs. AMD developed AMD64, the first major extension not created by Intel, which Intel later adopted as [[x86-64]]. During 2006 Intel began abandoning NetBurst with the release of their set of "Core" processors that represented a development of the earlier Pentium III.

A major alternative to Wintel domination is the rise of alternative operating systems since the early 2000s, which marked as the start of the [[post-PC era]].{{cite needed|date=February 2022}} This would include both the rapid growth of the smartphones (using Android or iOS) as an alternative to the personal computer; and the increasing prevalence of Linux and Unix-like operating systems in the server farms of large corporations such as Google or Amazon.

==The IBM PC compatible today==
{{See also|Legacy-free PC}}
The term "IBM PC compatible" is not commonly used presently because{{citation needed|date=September 2024}} many current mainstream desktop and laptop computers are based on the PC architecture,<ref>{{cite web|url=http://www.microsoft.com/whdc/archive/lf.mspx|title=Microsoft.com|website=[[Microsoft]] }}</ref><ref name="google1">{{cite book|author=Scott Mueller|title=Upgrading and Repairing PCs|url=https://archive.org/details/upgradingrepair100muel|url-access=registration|year=2003|publisher=Que Publishing|isbn=978-0-7897-2974-3|page=[https://archive.org/details/upgradingrepair100muel/page/956 956]}}</ref><ref>{{cite web|url=http://www.dewassoc.com/kbase/legacy.htm|title=What does "Legacy" mean in the world of computers?|access-date=2024-09-08|archive-date=2018-09-26|archive-url=https://web.archive.org/web/20180926213801/http://www.dewassoc.com/kbase/legacy.htm|url-status=dead}}</ref><ref>{{cite book|author=InfoWorld Media Group, Inc.|title=InfoWorld: The Desktop Revolution|url=https://books.google.com/books?id=WT0EAAAAMBAJ&pg=PA40|date=21 August 2000|publisher=InfoWorld Media Group, Inc.|issn=0199-6649}}</ref>{{rp|39–40}} and IBM no longer makes PCs. The competing hardware architectures have either been discontinued or, like the [[Amiga]], have been relegated to niche, enthusiast markets. In the past, the most successful exception was [[Apple Inc.|Apple]]'s [[Macintosh]] platform, which used non-Intel processors from its inception. Although Macintosh was initially based on the [[Motorola 68000 series]], then transitioned to the [[PowerPC]] architecture, Macintosh computers [[Mac transition to Intel processors|transitioned to Intel processors]] beginning in 2006. Until 2020, Macintosh computers shared the same system architecture as their Wintel counterparts and could [[booting|boot]] Microsoft Windows without a [[Orange Micro#PC compatibility|DOS Compatibility Card]]. However, with the [[Mac transition to Apple silicon|transition]] to the internally developed [[ARM architecture family|ARM]]-based [[Apple silicon]], they are again the exception to IBM compatibility.

The processor speed and memory capacity of modern PCs are many [[Order of magnitude|orders of magnitude]] greater than they were for the original [[IBM Personal Computer|IBM PC]] and yet backwards compatibility has been largely maintained{{snd}} a 32-bit operating system {{As of|2008|alt=released during the 2000s}} can still operate many of the simpler programs written for the OS of the early 1980s without needing an [[emulator]], though an emulator like [[DOSBox]] now has near-native functionality at full speed (and is necessary for certain games which may run too fast on modern processors). Additionally, many modern PCs can still run DOS directly, although special options such as USB legacy mode and SATA-to-PATA emulation may need to be set in the BIOS setup utility. Computers using the [[UEFI]] might need to be set at legacy BIOS mode to be able to boot DOS. However, the BIOS/UEFI options in most mass-produced consumer-grade computers are very limited and cannot be configured to truly handle OSes such as the original variants of DOS.

The spread of the [[x86-64]] architecture has further distanced current computers' and operating systems' internal similarity with the original IBM PC by introducing yet another processor mode with an instruction set modified for 64-bit addressing, but x86-64 capable processors also retain standard x86 compatibility.

==See also==
* [[AT (form factor)]]
* [[ATX form factor]]
* [[Baby AT]] form factor
* [[BIOS]]
* [[History of computing hardware (1960s–present)]]
* [[Homebuilt computer]]
* [[Influence of the IBM PC on the personal computer market]]
* [[PC speaker]]
* [[PC System Design Guide]]
* [[Personal computer]]
* [[x86]]
* [[MS-DOS]]
* [[CP/M]]
* [[IBM PS/2|PS/2]] - successor released by IBM that did not succeed, but many of its elements have been adopted by industry
* [[PC-9800 series]] - competing standard
* [[PowerPC Reference Platform]] → [[Common Hardware Reference Platform]] - competing standard for PowerPC
* [[UEFI]] (Unified Extensible Firmware Interface)

== References ==
{{reflist|30em}}

{{IBM personal computers}}

{{DEFAULTSORT:Ibm Pc Compatible}}
[[Category:Computer-related introductions in 1982]]
[[Category:IBM PC compatibles|*]]
[[Category:Computer hardware clones]]

[[lt:PC]]