Mail Archives: djgpp/1999/03/15/09:45:14
Eli Zaretskii writes:
> Maybe NT allows some ports to be accessed, or maybe some optional
> software package is the one which allows that access? Does anybody
> know?
My understanding is that it will only allow you to access services
that it knows about and can emulate, which includes things like the
VGA register set and standard keyboard/timer functions, but not
extended devices like most SVGA chipsets.
I've read about some methods for enabling direct access to other
ports, but don't know the details.
> The reason I'm asking is that the FAQ currently says not to expect
> non-standard SVGA modes to work on NT because port access is not
> available.
The non-standard mode-X resolutions seem to work ok (which is what
the original poster was talking about with reference to the Abrash
code), but they are still variants of the standard VGA. Some machines
do seem to be able to run in SVGA modes, because I've had reports that
a couple of people are doing this without any trouble, but in the
majority of cases it doesn't work at all. I think this must be down
to the individual chipset drivers. It certainly isn't safe to expect
SVGA modes to work: usually, they won't.
If anyone knows more about exactly what cards/drivers are ok, and
why some work while others do not, I'd be very interested to hear
it.
Shawn Hargreaves.
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