IBM PS2 HW Interface Technical Reference - Video Subsystems (September 1992)
The IBM Personal System/2 Hardware Interface Technical Reference — Video Subsystems, First Edition (September 1992), is IBM's 444-page volume on PS/2 video. It is the authoritative description of VGA and XGA as IBM implemented them.
What it contains
[edit | edit source]- Section 1, Introduction (1-1) — what a PS/2 video subsystem is, the BIOS video modes table (1-4), double scanning and border support (1-5), and the definitions of Type 2 (1-6) and Type 3 (1-8) video subsystems.
- Section 2, VGA Function (2-1) — the major components and a diagram of the VGA function, hardware considerations, Type 1 subsystem parameters, video memory organisation, the graphics controller and attribute controller, the full register set (2-39), programming considerations, the video digital-to-analogue converter (2-101) and the VGA video extensions (2-104).
- Section 3, XGA Function (3-1) — VGA compatibility, 132-column text mode, extended graphics mode, the XGA display controller registers (3-33) and the coprocessor description (3-90).
- Section 5 includes XGA sample code.
What it does not contain
[edit | edit source]Not a service manual. No FRUs, no adapter parts lists, no monitor data and no component values. It describes the function, not the board: for the physical XGA adapters see IBM PS2 XGA Display Adapter A Technical Reference (September 1990) and IBM PS2 HMM Supplement XGA-2 Display Adapter.
What it settles
[edit | edit source]This is the volume that settles what IBM meant by a "Type 1", "Type 2" or "Type 3" video subsystem — terms that appear in PS/2 model technical references without definition. It also carries the authoritative VGA register set, which is the reference to use when a machine produces a picture but the wrong one.
Download it here: IBM PS2 HW Interface Technical Reference Video Subsystems Sep92.pdf