CUMMINGS@S55.Prime.COM (03/12/90)
/* Written 9:26 am Mar 11, 1990 by lane@cs.dal.ca in S55:comp.sys.ibm.pc */
/* ---------- "How do VGA cards use the C000 memor" ---------- */
According to 386MAX, I have a ROM BIOS extension at C000-C400 which
seems resonable (I beleive this is typical for a VGA). However,
386MAX seems confused as to whether there is ROM or RAM at C400-C800.
Whatever, it won't use that area for high DOS memory. DEBUG says
there's something at C400-C600 but nothing (FF's) at C600-C800.
/* End of text from S55:comp.sys.ibm.pc */
What kind of ROM (PROM, EPROM, EEPROM, etc) is on your VGA card?
If you are right, and your VGA BIOS is from C000-C5FF, then it's
24K large. If your VGA card has a 32Kx8 EPROM on it, they may have only
programmed the first 24K (don't 27xxx EPROMs contain all FFs when erased?)
Probably cheaper to manufacture a card with one slightly larger EPROM than
with 3 smaller ones....
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Kevin J. Cummings Prime Computer Inc.
20 Briarwood Road 500 Old Connecticut Path
Framingham, Mass. Framingham, Mass.
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Std. Disclaimer: "Mr. McKittrick, after careful consideration, I've come
to the conclusion that your new defense system SUCKS..."
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