From:	sandmann AT clio DOT rice DOT edu (Charles W. Sandmann)
Subject:	RSX & GO32
To:	djgpp AT sun DOT soe DOT clarkson DOT edu (djgpp)
Date:	Thu, 17 Jun 1993 16:20:42 -0600 (CDT)

> Date: Thu Jun 17 14:44:28 1993
> From: grw AT tamu DOT edu
> To: djgpp AT sun DOT soe DOT clarkson DOT edu
> Subject: Re: gccdpmi1.zip on omnigate
> 
> 	I posted a message to this mailing list last Fri asking about
> this very thing, with no response that I have seen.  For those of you who
> don't know, RSXDJ is basically a replacement for go32 and ld (DPMI only).
> You do not have to recompile the whole compiler, but you do have to re-link
> it if you want it to use RSXDJ.  You don't have to do anything to the
> compiler if all you want to do is run *your* programs, then you just re-link
> them.

The RSXDJ module has the same type of limitations as the current GO32, in that
direct access to first Meg memory via 0xe000... does not work.  The V1.10 
library has functions which now do that in a environment independent manner.
The V1.10 read module is is also compatible with RSXDJ and does not need to
be patched.  Graphics are hopefully coming to GO32 under DPMI fairly soon.

> 	I think that go32 is much better than RSXDJ in some ways, namely
> its stability.  RSXDJ is vastly superior to go32 in others (namely it does
> not heave 4 megabytes of swap space down the toilet for each instance of
> itself).  I have floating point, so I have no knowledge of the floating point
> emulation of either.

By using the uploaded version of ld which produces COEF format images, GO32
will work under DPMI with the same memory footprint as RSXDJ.  You have to
relink, of course, to get this advantage.  The difference is that GO32 is
backward compatible with old images AND runs in non-DPMI environment without
changes.  It is the backward compatibility that costs you the extra memory.
If you have a good DPMI server, the unused part of the 4Mb doesn't get allocated
(just like GO32).  For example, under QDPMI I allocated 2GB of memory!

So, if you have a poor DPMI server, and are willing to relink, you can get
the memory advantages with COEF format and STILL RUN UNDER VCPI with GO32.

RSXDJ is also GPL, which prevents commercial use.  GO32 has different terms.

One area which RSXDJ has a clear advantage is for users without floating 
point hardware needing emulation.  This is not in the GO32 DPMI stuff 
currently, and I don't know of anyone working on it. 

Another advantage is that RSX DEBUG32 is listed in the documentation as working.
I haven't tried the package at all, but this isn't currently possible with 
GO32 DEBUG32 under DPMI.

Its an interesting package, and I hope to learn from it things which I can
hopefully help apply to GO32 in the future.

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