1.2.4 Graphics Array
The graphics array is located on the system board and operates in two
video modes:
1. VGA compatibility mode
2. XGA compatibility mode.
The system comes with at least four video-memory modules (512KB)
installed. Four additional sockets are available for installing
additional video-memory modules (maximum video memory is 1MB). When the
system is powered-on, the graphics array is in the VGA mode. In this
mode, all VGA alphanumeric text, and all-points-addressable (APA) graphics
video modes are supported. The maximum resolution in VGA compatibility
mode is 720-by-400 picture elements (PELS) in the text mode, and
640-by-480 PELS in the graphics mode. A maximum of 256 colors or 64
shades of gray is supported in VGA mode. Composite video is not
supported.
The graphics array is in the XGA mode only when enabled by the DOS Adapter
Interface or video device driver (example: MS Windows, OS/2 Presentation
Manager device drivers).
The XGA works with monochrome and color-analog direct-drive displays.
XGA supports the following:
+------------------------------------------------------------------------+
¦ System Board Video ¦ Resolution ¦ Colors ¦
¦ Memory ¦ ¦ ¦
+-----------------------+------------------------+-----------------------¦
¦ Four video modules ¦ 640 x 480 ¦ 256 16 ¦
¦ installed (512KB) ¦ or ¦ ¦
¦ ¦ 1024 x 768 ¦ ¦
+-----------------------+------------------------+-----------------------¦
¦ Eight video modules ¦ 640 x 480 ¦ 256 ¦
¦ installed (1MB) ¦ ¦ ¦
+------------------------------------------------------------------------+
The system board has a dedicated 32-bit expansion slot for video adapter
cards. This slot (J3) includes the auxiliary video connector (AVC) and
connects the VGA compatible video from the XGA (on the system board) to
video adapters (example: IBM PS/2 Image Adapter/A - 1MB).
IBM PS/2 Model 90 XP 486 HMR
Graphics Array
¦ Copyright IBM Corp. 1990, 1991
1.2.4 - 1
