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From:	eplmst AT lu DOT erisoft DOT se (Martin Stromberg)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: HELP with DPMI under DOS - Part II
Date:	21 Oct 2003 14:59:36 GMT
Organization:	Ericsson Erisoft AB, Sweden
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Charles Sandmann (sandmann AT clio DOT rice DOT edu) wrote:
: > 5) for Charlies Sandman: I will try to use sbrk(), I use to disable swap
: > file I will turn it on again (what about performance?). 

: When using over 500MB of memory with cwsdpmi r5, the page tables will 
: fault and cause slower performance.  If you have a disk cache, or put a
: 2MB swap file on a ram disk you can lower the performance hit.  

: But the fix for this is to use the current "test" release of cwsdpmi r6:

: http://clio.rice.edu/djgpp/csdpmi6t.zip

: I haven't messed with it in almost 2 years (not a lot of requests for more
: than 500MB of memory under DOS).  Eventually I planned to support 4GB, but
: I don't have a system with more than 2GB for testing right now.  I am
: considering making some major memory management changes for the final
: release which would limit the 4KB page space to the first 256MB and use
: 4MB pages for anything over that.  But trying to document that behavior,
: which would violate the DPMI specification, is a mess.

Why are 4MB pages or swapping the 4KB page tables necessary? Can't you
just allocate some memory above 1.1MB and put the page tables that
won't fit in conventional memory there?


Right,

						MartinS

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