From: sandmann AT clio DOT rice DOT edu (Charles Sandmann)
Message-Id: <9709101400.AA16125@clio.rice.edu>
Subject: Re: Shared memory (Was: Re: fread slowstart)
To: dz AT bo DOT dada DOT it (Diego Zuccato)
Date: Wed, 10 Sep 1997 09:00:48 -0600 (CDT)
Cc: billc AT blackmagic DOT tait DOT co DOT nz, djgpp-workers AT delorie DOT com
In-Reply-To: <34165050.3680@bo.dada.it> from "Diego Zuccato" at Sep 10, 97 09:46:24 am
Content-Type: text
Precedence: bulk

> Well, DPMI 1.0 have shared memory. DPMI 0.9 let us pass descriptors...
> It shouldn't be too difficult to handle both cases (shared memory isn't
> just a single handle shared between multiple processes ?).

DPMI 1.0 is designed with the following features:
1) Separate IDT for each client (no shared interrupts)
2) Separate LDT for each client (no shared descriptors)
3) Separate page tables for each client (no shared memory)

If you want to share memory between two processes, you must call special
DPMI 1.0 features to map that memory into each client.

It's possible, but it is radically different in the code to be supported
from how things are done with DPMI 0.9.