Contents of the READ.ME file
Author: Kent J. Quirk and Ed McNierney
Copyright: Copyright 1988 Ziff Communications Co.
Abstract: This file describes VGATEST and its messages.
VGATEST is a program designed to rigorously test the compatibility of a
VGA controller with the one on the system board of a Micro Channel equipped
IBM PS/2. This program is described in detail in "The VGA Compatibility
Test," Ed McNierney and Kent Quirk, PC Tech Journal, November 1988, p. 48.
To run it, simply type VGATEST followed by a filename, which is the
destination of all error messages. Messages may be sent directly to the
printer by typing VGATEST PRN. There is NO default filename (this helps
prevent accidental destruction of data). If you do not specify a filename,
you will be reminded.
VGATEST normally runs through 18 major tests in sequence, with frequent
pauses for the user to see the action. It also takes some option switches
which can be used to control this behavior:
-? or -h provide brief help, in the form of a list of the tests by name
and their number in sequence.
-tN runs test N only
-f runs selected test or tests without pausing. It's possible to
miss some failures this way, but the tests take much less time.
The eighteen tests are as follows:
1) BIOS: Mode Support
Checks all the standard supported video modes to see if they use the
2) BIOS: Cursor Operation
Checks the cursor positioning and size, in both emulation (CGA-compatible)
and non-emulation modes.
3) BIOS: Light Pen Support
Checks to see that the VGA does not claim to support a light pen.
4) BIOS: Multiple Pages
Draws on each page available to a mode and switches between them.
5) BIOS: Screen Scrolling
Scrolls a portion of the screen up, then down, and checks to make sure
it was done properly.
6) BIOS: Text Input/Output
Writes characters in various attributes in all modes, then attempts
to read them back.
7) BIOS: Graphics Input/Output
Checks every pixel on the screen, using all possible colors for that mode,
then reads them back.
8) BIOS: Palette/DAC
Checks palette setting in a wide variety of ways, including gray scaling.
9) BIOS: Save/Restore Video State
Checks this function of the bios for every video mode.
10) BIOS: Character Generator
Tests all the fonts available, including the ability to display two fonts
11) BIOS: Alternate Select
Tests the various subfunctions of this function, including setting the
number of scan lines in a font.
12) BIOS: Data Area Compatibility
Checks the BIOS data areas for compatibility with the ones used by IBM.
13) Hardware: General Registers
Checks the VGA General Register set for compatibility with the values
used by IBM. Checks the vertical retrace interrupt and status bit.
14) Hardware: DAC Registers
Checks the DAC registers for compatibility with IBM; checks to see that
they can be set correctly.
15) Hardware: Sequencer Registers
This checks the various sequencer register functions.
16) Hardware: CRTC Registers
Compares CRTC registers with IBM values.
17) Hardware: Graphics Registers
Tests the Graphics Registers by drawing on the screen and reading it back
in various modes.
18) Hardware: Attribute Registers
Tests various attribute register values, including panning and scrolling
(which also test the CRTC registers involved in this function).