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From: boegehol@delos.stgt.sub.org (Harald Boegeholz)
Newsgroups: comp.os.os2.misc
Subject: Undocumented video modes with MODE CO80,x
Keywords: VGA, full screen session, MODE
Message-ID: <2657@delos.stgt.sub.org>
Date: 1 Oct 90 11:16:12 GMT
Organization: delos, Stuttgart, West-Germany
Lines: 31

I accidentally discovered an undocumented feature of the MODE command
that I think may be interesting to some people on the net.

With MODE CO80,x it is possible to switch to a video mode with x lines
and 80 columns. The OS/2 Online-Manual says that legal values for x
can be 25,43, and 50, depending on the installed video adapter.

On an IBM PS/2 Model 60 running IBM OS/2 EE 1.2, I discovered that
in a full screen session a lot of other values are also accepted
and special video modes are set accordingly. I tried all numbers between
1 and 70 and came up with the following list of numbers that worked:

12, 14, 21, 23, 24, 25, 27, 28, 29, 30, 33, 34, 39, 40, 41, 42, 43, 45, 46,
47, 48, 49, 50, 54, 55, 56, 57, 58, 59, 60.

In the DOS-Box, I discovered that the following numbers worked:

12, 14, 21, 25, 28, 43, 50.

Strange, isn't it? Maybe someone can explain why exactly these numbers
work...

Btw, in a VIO-window, any value between 1 and 102 is accepted.

Maybe someone with an EGA adapter should give it a try too and let us know
the results?

I hope this was news to you after all...


Harald Boegeholz (boegehol@delos.stgt.sub.org)