AT&T PC 6300 - Page 271

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DIAGNOSTICS
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The DMA Memory Transfer Test takes data from the video
controller's memory and transfers it to a file that is created on
drive A. The size of this file depends on the available disk memory
space. The maximum size is 16 KB and the minimum size is 1 KB.
If less than 1 KB of disk space is available, the following error
message is displayed:
--- NO ERRORS IN VIDEO HARDWARE TEST
EXECUTION OF MEMORY/DISK TRANSFER TEST NOT POSSIBLE,
THE DISK IS FULL.
PRESS 'ENTER' KEY TO CONTINUE -
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A floppy disk file is created from data in the Video Controller
Memory by DMA transfer. The contents of the disk file is then
compared to the Video Controller Memory, see Customer and
System Test Error Messages.
2 - Monitor Test Patterns: Test patterns are displayed on the
screen so that proper alignment of the screen can be checked. The
test patterns include an alignment grid and a screen display full of
"H's".
3 - Character Set: Checks the Display Controllers ROM by
writing all available characters to the screen.
4 - Gray Scale: Checks the different colors or shades of grey or
green phosphorous displays, as the case may be. The various
colors are: Black, Blue, Red, Magenta, Green, Cyan, Brown, White,
Dark Grey, Light Blue, Light Red, Light Magenta, Light Green,
Light Cyan, Yellow, and Intense White.
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