RE: drivers - again, i.e. DirectX <-> DGA

["Suhaib Siddiqi" <Ssiddiqi@InspirePharm.Com>]

> Subject: drivers - again, i.e. DirectX <-> DGA
>
>
> On Thu, 19 Aug 1999, Suhaib Siddiqi wrote:
>
> .....
> > > Question: I assume it's OK if I rewrite the internals of
> functions like
> > > xf86ReadBIOS (in cygwin_mmap.c), to use NT API calls (e.g. calls to
> > > DeviceIOControl)?  Since this code is going to be very
> platform-specific
> > > anyway, I'm thinking there's not much point in trying to use
> Unix-style
> > > functions like device_open to access NT drivers.
>
> In fact. Even the OS/2 implementation is, in my opinion, unusable except
> as a hint on what is needed (i.e., a direct port would be intrinsically
> whizmical).

Agreed!!! The Win32 API lacks the equivalent of many DOS32 stuff.  You
cannot take Os/2 code and simply recompile it on Win32.  One commercial
vendor (www.codefx.com) claims their tools can do that.  I sent them code
from Holger Veit as a test case.  They failed and since then they have
stopped e-mailing me to license their Os/2 to Win32 API auto-conversion
tools.

> - DirectX 5+ is available for all the Win32 platforms (except for Win32s
>   and CE, which are not relevant in our context); this means, among other

No that is not quite correct.  DirectX 5.0 does not work on Nt.  The only
thing wich work on Nt 4.0 is DirectX 3.0, i.e. also with Service Pak 4.0 or
3.0.

Direct 3 does not work on Win2K

>   things, you may avoid using separate XFree86 drivers for Windows 95,
>   Windows 98, NT 4.0 and NT 5.0/Win2k (since their video subsystems
>   are non-trivially different; just think of the PnP or multi-monitor
>   support).

We are aiming for it, but there are pitfalls.  DDK does  not fully support
Win 9x and DirectX higher then 3.0 does not work on Nt 4.0.  These are the
Micro$oft gimmiks to sell more different versions of OS and force
the developers to maintain several versions of their sofwtare  for
different version of Windows.

> - DirectX apps may be installed and used by non-administrator users (and
>   can't nuke the whole system down to its knees, which is especially
>   important for many people).
> - As I told you before, I would not be surprised if DGA could be directly
>   mapped on top of DirectX.
>
> I have not used DirectX (a friend of mine did, and yelled for some
> months), but I read its documentation thoroughly and I know it can be
> done - VMware itself is a proof in concept, though its goals were pretty
> different.

VMware can be a proof in concept but I was not very impressed.  First VMWare
work on NT only.  Second it supports DX 3.0 on Nt 4.0 because
any higher version of DX on NT 4.0 will pop-up a box with DLL initialization
errors.


>
> Please send me details of the DGA thing (I think it might be interesting
> having both 3.3.x and the preliminary 4.0 specs)
>


What is DGA? anyway :-) Do I already have something like that in my Xfree
code?

Regards
Suhaib


> Best regards
>
> 	 		Federico Bianchi
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