The program VS generates a list of video modes supported by your VESA bios.
(Other than to tell you that you don't have a VESA bios, it will not do
anything for you if you don't have a VESA-aware video system.)  It may also
indicate support for the lower, non-SVGA video modes (as well as non-VESA SVGA
modes).  However, this is not standard from one VESA bios to the next.  Hence,
you should not conclude that you don't have support for these lower modes just
because VS doesn't confirm support for them.  Simply run VS from the DOS
command line (there aren't any command line arguments) and it will generate
the file MODES.LST.  (IF you're on the same disk that VS resides on, this output
file will be in your current directory.  Otherwise, it will be in the root
directory of where VS.EXE is.)  If you have a VESA system, in addition to
telling you that, VS will print your VESA version number to the screen and
then ask you whether or not you want to confirm mode support graphically.  This
is done by drawing a box bounding your screen and is only done for modes that
support pixel plotting via bios calls.  If you can't see the box for each mode
being tested, you may not have support for that mode, in spite of the fact that
your VESA bios reports support for it.  (I usually run VS twice--once with no
graphical mode confirmation and then using graphical mode confirmation, after
renaming the first MODES.LST so it doesn't get overwritten.  Then I compare the
two resulting files.)  The first column of numbers gives the hexadecimal bios
mode numbers supported by your video board.  (Whether or not your monitor can
operate in these modes is a separate issue.  This may be indicated by the "type
of support" in column six, but I'm not really sure.)  The second column gives
the type of mode, text or graphics ("grfx").  The third column gives the maximum
supported resolution and number of colors.  (Resolution is in characters for
text modes and pixels for graphics modes.)  For a 32-bit color mode, instead of
printing the actual number of colors, "2^32" is printed.  The fourth column
gives the number of bit planes per pixel, the fifth column gives the number of
pages supported, and the sixth column gives the type of support, hardware,
software (bios), or both.  (It's entirely possible for you to have hardware that
supports any given video mode but yet that mode is not necessarily supported by
your bios.)  This functionality is built into VS (and VS1) just in case your
bios supports it.  If the number of pages is listed as zero, don't panic.  This
is most likely (definitely?) just an indication that your particular VESA bios
doesn't report this information.  The opposite side of the coin is that you
can't necessarily trust this information even if it's non-zero.  I have not
found very many VESA systems that reliably support this function.  It is
included merely because a reference indicates that this aspect of the VESA bios
should be functional.

Even if you do choose to confirm mode support graphically, there are two
situations in which video modes will be listed in MODES.LST that have not been
so tested.  These are if your VESA bios does not report any extended
information for the particular mode or the particular mode is not listed as
supported in bios.  (In these situations, VS just lists the mode as supported
because your VESA bios listed it as such.  These untested modes will be fairly
obvious.  Either the number of bit planes and pages will be zero, along with
the resolution not being given, or else the type of support in column five will
be something other than "hardware/bios.")

Note that, as long as you don't want to confirm mode support graphically, VS
does not actually attempt to make ANY change to the video mode your monitor or
video board is in.  Hence, if you're worried about possible damage to your
monitor due to attempting to put it in a mode that it can't deal with, you
should use the no-confirmation mode.  (I have never actually seen a monitor
damaged in this way, and I've tested VS out on a great many monitors, attempting
to put them in a great many modes which they obviously didn't support.  However,
this is no guarantee and I must insist that you use VS at YOUR OWN RISK.)

The program VS1 is used to analyze a specific video mode.  The DOS command
line syntax is

VS1 hex-mode

(If you run VS1 without any arguments, it will tell you this.)  VS1 prints out a
little more information about the mode than that specified in MODES.LST.
(This is still only a subset of the information that's generally available.
Also, like VS, VS1 can only do this if extended information is available.
If it isn't, VS1 will tell you.)  One output of VS1 is a pointer to where the
list of supported screen modes MAY be stored in your computer's memory.  I say
"MAY" because there's no strong guarantee that this memory location isn't
volatile.  This is where VS gets its list of modes from.  This data is only
output by VS1 in case you're a DEBUG user (or user of some similar program) and
you want to do your own exploring.  And of course, like VS, VS1 is of no use to
you if you don't have VESA hardware other than to tell you that you don't.

If your VESA version is 2 or more and you do not specify a video mode on the
command line, VS1 outputs additional information about your video card, i.e.,
your OEM software version, the vendor and product names, and your "product
revision string."
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