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From:	Charles Sandmann <sandmann AT clio DOT rice DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: HELP with DPMI under DOS
Date:	Mon, 20 Oct 2003 16:29:00 CDT
Organization:	Rice University, Houston, TX
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> I'm tryuing to allocate an array of 1023Mb on a PC with 1Gb RAM installed
> but I can't success. 

How are you trying to allocate the memory?  I would suggest you use
sbrk() to allocate such large chunks.  I also suggest you remove EMM
providers from your configuration, and tell us what GO32-V2 prints.

In my testing, I routinely allocate 2GB of memory for testing CWSDPMI,
so I know it works.  It will fail if you disable paging and try to allocate
more than about 500MB.  The long term fix for this is to use 4MB pages,
which is available in CWSDPMI r6 wip/test release.

> I try do modify the parameters of cwsdpmi with
> cwsparam, I also try pmode/dj, but nothing to do. 

I've also allocated 2GB of memory with the most recent pmode/dj - so this
points to maybe something in your configuration or how you are trying to
allocate the memory.

> I'm writing an application
> memory critical and I'm planning to buy 2Gb more memory (3Gb total) do
> someone have some idea to how can I allocate this memory in a single array
> under DOS?

If you are planning to use more than 2GB, you *MUST* use sbrk() for 
allocation.  (There are limitations in malloc() which will prevent you
from using more than 2GB in a single allocation).  

Using 3GB (or 4GB) of memory under DOS in a single array has generated
lots of email to me - but so far no one has built a machine and tested
more than 2GB of physical usage - and sent me results.

You will want to use the r6 test release if you plan to use more than
500MB.

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