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.  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.)  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, in fact, yet to find a VESA system that reliably supports 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 by *both* hardware and 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.  (VS1
does not print this information out if this memory location lies in the lower
640K; such locations are, of course, volatile.  Also, I say "MAY" because
there's no strong guarantee that the memory above 640K isn't volatile.  Some of
it certainly is!)  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 don't have VESA hardware other than to tell you that you don't.