Re: Video Mode 13h in windows XP ... impossible?

From: Beth (BethStone21_at_hotmail.NOSPICEDHAM.com)
Date: 02/20/04 

Date: Fri, 20 Feb 2004 15:17:59 -0000

The Half A Wannabee wrote:
> wolfgang kern wrote:
> > My (fastest) way is using direct hw-access,
> > but this goes a bit deeper and needs hardware specific routines,
> > so I can only support a few known cards that way,
> > for all 'unknown' stuff I have to use VBE/VESA method.
>
> Nice post. I was thinking.Would it be possible to install a driver
in
> windows to record anything send to the Nvidia driver and from the
Nvidia
> driver to the hardware ? I do not intend to do this, but just for
> curriosity. My only question is, would it be possible ? Beth, Wolf.
Anyone?

Never attempted any such thing so this is just "guessing"...but I
can't think of any particular reason why you couldn't "install" your
own display device driver, which simply "propogates" things to the
real nVidia driver or back from that driver to Windows (and takes a
"sneaky peek" at it, recording the stuff :)...there'd be an inherent
"slow down" because of this extra "layer" but I can't directly think
of any reason why it couldn't work...basically, write a display device
driver which simply acts as a "middle man" between Windows and the
nVidia driver, recording things but otherwise "propogating" them back
and forth so all the graphics still happens as expected...the only
thing that might be a problem is anything that requires precise timing
but there shouldn't actually be anything that demands such precise
timing generally because, like, all cards respond at different speeds
and have different driver code (some better or worse than others ;)...

Of course, the big issue here, though, is _WHY_ do this? After all, to
write your "display driver" code, you'd get your hands on Microsoft's
"display driver" specifications and follow them, right? In which case,
why do you need to spy on the nVidia driver? The messages Windows
sends it and that it sends back to Windows are, of course, exactly
those specified for _any_ Windows display driver...this part of the
"interface" in the OS is, in fact, abstract and completely
standardised...it has to be because Windows _itself_ uses these
display drivers to draw the Windows desktop and implement DirectX and
so on and so forth...this _ISN'T_ the place where the "big mystery" is
kept...the bit nVidia - the selfish sods that they are - keep from
developers is the interface between the display device driver(s) and
the _hardware_...this is the bit which tells us how the actual
hardware cards work...and that, yup, nVidia keep from anyone knowing
by not publishing specifications, which I'm guessing is your
"inspiration" in asking this "can we spy on the driver as it's
running?" question...alas, you could do this but that's not actually
the bit that's kept hidden..._Microsoft_ define the Windows -> display
driver interface and the specifications for that are available from
Microsoft when you look in the right places (the DDK is a nice place
to start...but there are sometimes some additional things for display
drivers to do with supporting DirectX properly that you should also
look out for any "DirectX DDK" too, which contains "additionals" about
some of the DirectX specific stuff to supplement the basic stuff in
the DDK...I know that DirectX 7 had such an "additional" addressing
how to make the accelerator stuff work much better...you just have to
rummage around...Microsoft are totally happy to release this stuff
because, as I say, their monopoly actually kind of depends on the fact
that hardware manufacturers write all the device drivers - if they
didn't, then Windows would start to lose its unrivalled hardware
support - so MS are actually happy to thrust this into people's
faces...they kind of _want_ you (desparately, even ;) to use their DDK
and write drivers for all your new hardware so that they can sell
Windows on: "Supports all hardware!"...oh, they'll _never_ willingly
release the _source code_ of Windows itself, indeed...but all the
"interfaces" to actually _use_ Win32, they can't give enough
away...creating "MSDN", the "Knowledge base", free downloads of Win32
header files, SDKs, DDKs, etc....on this front, in fact, Microsoft
actually _so_ want people to have this information and use it that
you'll note that even something "open source" like Linux - even with
built-in "man" pages - is actually trying to "play catch up" on giving
out the documentation because MS are giving away much more information
and support on this stuff...they don't hide this "interfacing" stuff
at all...quite the contrary, Microsoft are kind of trying to thrust it
all in people's faces - because if you use Win32, then you're
_supporting_ Windows (the point Rene doesn't quite get ;) so they are
overjoyed at you writing all your software to their proprietary
standards and giving _them_ your trade (which includes all _your
users_ of your program too, of course ;) rather than Linux or OS/2 or
something instead - and, in fact, amazingly, no-one comes close to
Microsoft...this is another element of their "monopoly"...they _keep_
the monopoly with the _proprietary standards_ on the hardware device
drivers...but I was around when Win3.x was becoming "the" OS and
Windows starting pushing all the "alternatives" away as it _gained_
monopoly in the first place...and, this is why people, in fact, go on
and on at Linux developers to "make the bloody thing more
user-friendly!!!"...they won the monopoly in the first place by simply
making Windows the brain-dead simple monster that it is...full of
"help files" this and "here, have free SDKs and header files to
download" that...it's where Linux does, unfortunately, fall down:
There's no "service" ethic in the Linux community...where MS set-up 24
hour helplines, Linux people pour ridicule on a poor newbie user who
doesn't understand what "fsck" means or how to use it...indeed, _IF_
Linux wants to "win" the desktops (although, of course, if it doesn't
then that's perfectly acceptable too...it can, of course, choose to
remain a "niche" thing for developers and "power users"), then one
word and attitude needs to develop: a "service" ethic...as a
commercial company, Microsoft kind of get this stuff naturally into
the bargain...the old "the customer is always right...OR, basically,
you make no money!"...Linux gets the "no, the OS should be _good_!!"
but doesn't have the "play to the audience" attitude needed to get it
accepted to a wider - yes, _mostly Clueless_ - desktop market :)...

Anyway, you could probably do that...but, if you did, you'd wonder why
you bothered ;)

Beth :)