VidTest 2.1 (C)Copyright 1996 William H. Decorie  All rights reserved

!!!! WARNING: THIS PROGRAM CAN CAUSE SERIOUS AND PERMANENT DAMAGE TO
     YOUR MONITOR.  READ THIS ENTIRE FILE BEFORE RUNNING THIS PROGRAM !!!!

        This program will test your VGA/SVGA adapters video memory.  Most
commercial diagnostic programs will only test the first 256K of video
memory, because this is the maximum amount on a real VGA.  Most adapters
out there now have 1MB of RAM, with some having 2MB or even 4MB!  Obviously
you need a program that will test ALL of your memory if you think you have
a problem.

        The program relies on VESA function calls to bank switch the memory
for testing, so the adapter must have VESA built into it's ROMs, or you must
have a VESA TSR loaded for this program to work.  I highly recommend the
UniVESA driver (I think it's called UniVBE now).  My program only requires
the VESA version to be 1.1 or higher.

        The amount of video memory is determined using a VESA function call.
On some adapters this function returns erroneous information.  If my program
cannot accurately determine how much video RAM you have, it will say so
but still allow you to test the memory.  Only those mode which are 1) listed
as being supported by the adapter (again, using a VESA function call) and
2) don't require more RAM than the card has are shown in the choice list.

        Choose the mode which will work on your monitor which uses the most
RAM to make sure that ALL of your RAM is tested.  Some cards only allow
access to a portion of the video RAM for those modes which don't need more
than half.  Of course, the modes which use less RAM will test faster because
the CPU doesn't have to wait to access that portion of video memory which
isn't being displayed.

        When you first run this program for a given mode, KEEP YOUR FINGER
ON YOUR MONITOR'S POWER SWITCH!!!  If your monitor starts making a funny
noise (usually a high pitched whine), TURN YOUR MONITOR OFF IMMEDIATELY!!!
Allow the program time to finish testing the RAM before turning the monitor
back on.  (At a minimum, on old slow ISA cards, allow about one second for
every 8K to test.)

        The program will create a text file in the current directory called
VIDTEST.LOG, which will contain the status of the test.  The status will
also be displayed on the screen after the test.

        You can also use this program to compare the speed of two video
cards in the same machine.  The status log will show you how long it took to
test the memory and at what rate (in K/sec).  Just test both cards USING
THE SAME MODE and compare the test rates.  The card with the higher rate is
can be accessed faster and will therefore (usually) be the faster card.

        PCI and, to a lesser extend, VLB cards will usually fly.  Older ISA
cards will probably take a while to test.
