Editing Video Graphics Array (section)

== Hardware design ==
[[File:IBM VGA 90X8941 on PS55.jpg|thumb|VGA section on the motherboard in [[IBM PS/55]] |alt=|left]]The [[Palette (computing)|color palette]] [[Random-access memory|random access memory]] (RAM) and its corresponding [[digital-to-analog converter]] (DAC) were integrated into one chip (the [[RAMDAC]]) and the [[cathode-ray tube]] controller ([[Video display controller#Types|CRTC]]) was integrated into a main VGA chip, which eliminated several other chips in previous graphics adapters, so VGA only additionally required external video RAM and [[timing crystal]]s.<ref>{{Cite web |last=Peddie |first=Jon |title=Famous Graphics Chips: IBM's VGA {{!}} IEEE Computer Society |url=https://www.computer.org/publications/tech-news/chasing-pixels/Famous-Graphics-Chips-IBMs-VGA/ |url-status=live |archive-url=https://web.archive.org/web/20221128083601/https://www.computer.org/publications/tech-news/chasing-pixels/Famous-Graphics-Chips-IBMs-VGA |archive-date=2022-11-28 |access-date=2022-12-27 |website=[[Institute of Electrical and Electronics Engineers#IEEE Computer Society|IEEE Computer Society]] |date=12 March 2019 |language=en-US}}</ref><ref>{{Cite journal |last=Thompson |first=Stephen |date=1988 |title=VGA ‒ Design choices for a new video subsystem |journal=IBM Systems Journal |publisher=IBM |volume=27 |issue=2 |pages=185‒197 |doi=10.1147/sj.272.0185}}</ref>

This small part count allowed IBM to include VGA directly on the PS/2 motherboard, in contrast to prior IBM PC models{{snd}}[[IBM Personal Computer|PC]], [[PC/XT]], and [[PC AT]]{{snd}}which required a separate display adapter installed in a slot in order to connect a monitor. The term "array" rather than "adapter" in the name denoted that it was not a complete independent expansion device, but a single component that could be integrated into a system.<ref name=":0" />

Unlike the graphics adapters that preceded it ([[IBM Monochrome Display Adapter|MDA]], [[Color Graphics Adapter|CGA]], [[Enhanced Graphics Adapter|EGA]] and many third-party options) there was initially no discrete VGA card released by IBM. The first commercial implementation of VGA was a built-in component of the IBM PS/2, in which it was accompanied by 256&nbsp;KB of video RAM, and a new DE-15 connector replacing the DE-9 used by previous graphics adapters. IBM later released the standalone ''IBM PS/2 Display Adapter'', which utilized the VGA but could be added to machines that did not have it built in.<ref>{{Cite web|date=1987-04-02|title=THE IBM PERSONAL SYSTEM/2 (TM) DISPLAY ADAPTER, THE IBM PERSONAL SYSTEM/2 DISPLAY ADAPTER 8514/A AND|url=https://www-01.ibm.com/common/ssi/printableversion.wss?docURL=/common/ssi/rep_ca/4/897/ENUS187-054/index.html&request_locale=en|access-date=2020-08-16|website=www-01.ibm.com|language=en-US}}</ref><ref name=":0">{{Cite news |last=Rosch |first=Winn |date=December 22, 1987 |title=IBM VGA Adapter Card: 256K Video RAM, 17 Display Modes |pages=35 |work=PC Magazine |url=https://books.google.com/books?id=gC-DsOtl2MgC&q=IBM+PS%2F2+display+adapter&pg=PA35}}</ref>

On some machines and cables, pin 9 was missing. All pin 9 does is power an EEPROM chip in the monitor which tells the graphics card the capabilities on the monitor. Systems or cables missing this are likely using an older version of VGA.