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CD Player 1994 January
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CdPlayer94-01.iso
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vesa400.txt
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1993-08-06
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VESA400 version 1.00
August 6, 1993
PURPOSE
VESA400.COM is a very small TSR (occupies only 1/2 K when loaded).
It will allow video cards with VESA BIOS extensions (either in ROM, TSR,
or device driver) to run programs which require mode 100h (640x400x256) to
run on cards which do not support that mode.
REQUIREMENTS
Your video card must me VESA compatible, and must support mode 101H
(640x480x256).
HOW IT WORKS
VESA400 will intercept set mode and get mode calls (as well as a
few others) for both the normal interrupt 10 functions and the VESA interrupt
functions (int 10h,4fh). It inserts mode 100h into the VESA mode list so
that calling programs will think that mode 100h is supported. It then
substitutes mode 101h when the program attempts to switch to mode 100h.
LIMITATIONS
Because 640x480 mode is substituted for 640x400 mode, your display
will appear slightly "sqaushed" with 80 blank pixel lines on the bottom.
But hey, your program runs, doesn't it?
WHY
In reviewing some vendor forums it appeared that some users were
really desperate for 640x400x256 mode. I simply can't understand why a
hardware vendor who produces a card which supports higher modes wouldn't
support this one as well. To really produce 640x400x256 mode would
require an intimate knowledge of each chip set and how to program their
super vga registers. This is a stopgap measure.
PROBLEMS
I've only tried this with 2 programs and it works for both. The
worst thing that could happen is that it could whack the video and you
would have to reboot. However, because their are always those jerks out
there who take something for free and then sue your butt, USE THIS PROGRAM
AT YOUR OWN RISK. I TAKE NO RESPONSIBILITY OF ANY KIND FOR ANY DAMAGE CAUSED
BY THIS PROGRAM.
Please report anything that looks weird, alonjg with the program
name which caused the weirdness. CSERVE mail would be best.
Richard A. Bross
72236,2002