Editing IBM Personal Computer (section)

=== Display ===
[[File:IBM PC XT color.jpg|thumb|IBM PC with MDA monitor]]
While most home computers had built-in video output hardware, IBM took the unusual approach of offering two different graphics options, the [[IBM Monochrome Display Adapter|MDA]] and [[Color Graphics Adapter|CGA]] cards. The former provided high-resolution monochrome text, but could not display anything except text, while the latter provided medium- and low-resolution color graphics and text.

CGA used the same scan rate as [[NTSC|NTSC television]], allowing it to provide a composite video output which could be used with any compatible television or [[composite monitor]], as well as a direct-drive TTL output suitable for use with any [[RGBI interface|RGBI]] monitor using an NTSC scan rate. IBM also sold the 5153 color monitor for this purpose, but it was not available at release<ref name="williams1982012">{{cite news|author=Williams, Gregg|date=January 1982|title=A Closer Look at the IBM Personal Computer|page=36|work=[[Byte (magazine)|Byte]]|url=https://archive.org/stream/byte-magazine-1982-01/1982_01_BYTE_07-01_The_IBM_Personal_Computer#page/n37/mode/2up|access-date=October 19, 2013}}</ref> and was not released until March 1983.<ref>{{cite web |publisher=IBM |type=Announcement letter |id=183-002 |title=IBM Color Display, 5153 Model 1 For IBM Personal Computer |date=February 4, 1983 |url=https://www.ibm.com/docs/en/announcements/archive/ENUS183-002}}</ref>

MDA scanned at a higher frequency and required a proprietary monitor, the [[IBM 5151]]. The card also included a built-in printer port.<ref name=":1">{{Cite book|url=https://archive.org/stream/byte-magazine-1982-01/1982_01_BYTE_07-01_The_IBM_Personal_Computer#page/n37/mode/2up|title=Byte Magazine Volume 07 Number 01 - The IBM Personal Computer|date=January 1982}}</ref>

Both cards could also be installed simultaneously for mixed graphics and text applications.<ref>{{Cite web|title=Dual-Head operation on vintage PCs|url=https://www.seasip.info/VintagePC/dualhead.html|access-date=August 16, 2020|website=www.seasip.info}}</ref> For instance, [[AutoCAD]], [[Lotus 1-2-3]] and other software allowed use of a CGA Monitor for graphics and a separate [[monochrome monitor]] for text menus. Third parties went on to provide an enormous variety of aftermarket graphics adapters, such as the [[Hercules Graphics Card]].

The software and hardware of the PC, at release, was designed around a single 8-bit adaptation of the ASCII character set, now known as [[code page 437]].