Date: Sat, 02 Dec 2000 10:25:43 +0200
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
Sender: halo1 AT zahav DOT net DOT il
To: Mark <mark1smi AT almaden DOT ibm DOT com>
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CC: djgpp AT delorie DOT com
In-reply-to: <3A281B86.19CFEB8A@almaden.ibm.com> (message from Mark on Fri, 01
	Dec 2000 13:43:35 -0800)
Subject: Re: vxd file system drivers and DPMI
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> From: Mark <mark1smi AT almaden DOT ibm DOT com>
> Newsgroups: comp.os.msdos.djgpp
> Date: Fri, 01 Dec 2000 13:43:35 -0800
> 
> Even if you don't understand this first paragraph, you still may be able
> to help.

IMHO, you explained too little of the subject matter.  Please consider
expaining more, as people here do not generally mess with VxD's and
the Windows kernel.

> So, I am trying to write such a program with DPMI which will basically
> just do gethostbyname for my kernel vxd. However, I have 2 questions.
> First, how do I call into my DOS Box program from the kernel?

The kernel is supposed to know everything about the selectors and the
memory mapping used by the DOS Box, right?  If so, a protected-mode
far call using the DOS Box's CS selector should do the trick, I think.

> And
> second, if this is an asynchronous call, how do I call into my kernel
> vxd from my DOS Box program?

One possibility is to provide a real-mode address which the DOS Box
could use as a far call, via the appropriate DPMI function.

Another possibility is to provide a function of some real-mode
interrupt (e.g., 2Fh) which the DOS Box could call.