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Virtua Chess demo terminates with "card not 100% compatible VGA" error

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First post, by MrFlibble

Posted on 
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I was trying to play the Virtua Chess demo for DOS, however I keep getting the following error at startup:

vchess_002.png
Filename
vchess_002.png
File size
1.65 KiB
Views
907 views
File license
Fair use/fair dealing exception

I've tried all available machine=svga_ options available plus vgaonly without effect, both in 074-3 and SVN builds. The debugger shows nothing that would point at the cause of the error.

However, the demo runs without trouble in DOSBox-X.

The game is listed as "supported" in the DOSBox compatibility database, although another user reported what appears to be the same error back in 2005.

DOS Games Archive | Free open source games | RGB Classic Games

Reply 1 of 3, by ripsaw8080

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The game has a test that expects raster ops to work in text mode, and while they technically should work in all modes, AFAIK they're only really used in graphics mode. Official DOSBox does not implement raster ops in text mode, presumably for performance reasons, so that may not change just to support this game's unusual test.

The attached TSR program will bypass the shareware version's test; simply run it in DOSBox before running the game. I've made similar TSRs for the commerical and pro versions as well, as they use a similar (but not exactly the same) test.

Attachments

  • Filename
    vcsfix.zip
    File size
    200 Bytes
    Downloads
    92 downloads
    File license
    Fair use/fair dealing exception

Reply 3 of 3, by Pat51100

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ripsaw8080 wrote on 2021-11-30, 18:23:

The game has a test that expects raster ops to work in text mode, and while they technically should work in all modes, AFAIK they're only really used in graphics mode. Official DOSBox does not implement raster ops in text mode, presumably for performance reasons, so that may not change just to support this game's unusual test.

The attached TSR program will bypass the shareware version's test; simply run it in DOSBox before running the game. I've made similar TSRs for the commerical and pro versions as well, as they use a similar (but not exactly the same) test.

Hi.
Can you please post the file for the commercial version (not the demo) ?
I have to execute the file vcsfix.com before to launch vc.bat. That's it ?
Thank you for your answer.

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