Hi,
I've just bought a Tyan S2466-4M Mobo, an Athlon XP 2400, and a 512Mb stick DDR of PC2100 memory (not registered) . I've installed then installed Dos 6.22 (yes DOS ! in order to get a PCB routing package running (Cadstar 7 - it doesnt run well under Windows).

The software puts the VGA into a 16 colour 640*480 graphics mode, and then runs OK, except for the fact that the characters are illegible. Difficult to describe, but basically instead of normal characters, it's just a random selection of dots. The software runs fine, and I can see all the PCB routes, pads, colours etc, just the text is unreadable.

I've tried 3 different AGP graphics cards (2 based on a GeForce 4 MX440, and one on an older ATi Rage II), and all three are the same.

It seems to me that the processor can't read the VGA character set properly. Either that or DOS/EMS doesn't like 512MB, and keeps putting data in memory it can't then access.

The software (Cadstar7) works well on other (non XP) Athlon machines using the same graphics cards, and up to 384MB, so I'm rapidly comming to the conclusion its either the MPX chipset, or possibly the XP processor. Trouble is, I don't have another machine with an XP processor in it to rule the processor in or out.

Anyone got any ideas?

Incedentally, I've also installed Windows 2000, and run Cadstar in a Dos shell, with identical results! I reverted to DOS to rule out any Win2K issues.

Cheers,
Judwin

I've seen funnies like this too, and don't think it has anything to do with the GFX card. I tried out and old DOS app too, and everything worked, except the characters were illegible - sorta like you described - with random pixels in a 8x8 character. I think it has to do with the character sets that the program 'calls'. I think the app refers to a SYSTEM font library or something. Not sure exactly how this works, but I have not found a fix - luckily it IS a game, so the numbers don't mean much - just press space and you're in. Are you loading Himem and stuff? perhaps you need to look at some of the regional settings - or character code sets?

Hope this helps - been a while since I ran DOS

Good Luck. Perhaps you can try PCDOS, or DR-DOS? maybe they work a little better.

-------------------------
The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.

Yes - the 'bug' you are describing does sound like the same one. An 8*8 array of seemingly random pixels where any characters should be.

RE: think it has to do with the character sets that the program 'calls'.

Yes that's my assumption too, but if I remember correctly, the character sets are stored in the VGA card in it's BIOS rom. I know these GFX cards work in other machines, so there can't be anything wrong with the cards or their BIOS's. Which is why I'm suspecting the MPX chipset, coz I've read it does 'funnies' when shadowing BIOS roms.

I've tried with and without himem, with and without EMM386, all the same. And its identical when running in a DOS shell from Win2K. So I don't think it's got anything to do with Microsoft (for a change !.

I haven't tried using alternate language regional settings - Ill give it a go when I get home.

Cheers
Judwin