I maintain an open source video driver for a CAD package that I use,
(non-relevant details on http://airborn.com.au/layout/easytrax.html ).

I need to develop a 16 bit driver --> win32 Virtual Device Driver (= DLL)

I can write the 16 bit driver, and I think I can write the DLL - but
I'm missing the detail on how to make the 16 bit driver call the DLL.  

See:  http://www.osronline.com/ddkx/other/vdd_2mya.htm
or:   http://msdn.microsoft.com/library/default.asp?url=/library/en-us/other/hh/other/vdd_1d9de737-db17-45d3-9b3b-7c7fafde3856.xml.asp

These describe exactly what I want to do, but the stop just short 
of telling me how I call "RegisterModule" or "DispatchCall" - 
what I want is detail on what/where to call.

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Clarification of Question by airapollo-ga on 18 Oct 2004 19:30 PDT

...I need a solution for NT/XP, as referred to in the links...

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Clarification of Question by airapollo-ga on 19 Oct 2004 22:32 PDT

... apparently the Windows DDK contains "Virtual DOS Driver 
(VDD) Samples" ... if someone with more knowledge is not able
to help, I've ordered this, I'll just wait for it to arrive ...

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Clarification of Question by airapollo-ga on 08 Nov 2004 08:57 PST

For anyone who is following this thread, the answer is
C4h,C4h,58h,0Nh, where N=0,1,2,3 for RegisterModule, 
UnRegisterModule, DispatchCall and VDDUnSimulate16
respectively.  The answer was kindly provided on another
forum - unfortunately the DDK CD never arrived...

You just place the values in your 16 bit code and execute 
them, the rest happens by "NTVDM magic"  ... Thanks & Bye!

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Clarification of Question by airapollo-ga on 08 Nov 2004 09:01 PST

Umm, sorry, take "VDDUnSimulate16" out of that list.
The numbers I gave for that are wrong, and it does
not apply to the situation in any case.