From:	gfoot AT mc31 DOT merton DOT ox DOT ac DOT uk (George Foot)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Virtual memory??
Date:	9 Mar 1997 15:24:08 GMT
Organization:	Oxford University
Message-ID:	<5fukmo$3pj@news.ox.ac.uk>
References:	<3322B8CB DOT 4164 AT earthling DOT net>
NNTP-Posting-Host:	mc31.merton.ox.ac.uk
Lines:	37
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

David.M.Reed (dave AT earthling DOT net) wrote:
: I have only had DJGPP for a couple of days, and I have noticed some very
: strange things happening when I try to allocate large amounts of memory.

: I tried to allocate a very large block of memory with malloc()/xmalloc()
: - about 8 Mb (on a 16Mb PC), and then fill this memory with data.

: If I run it through DOS with CWSDPMI, it runs fine, but when running
: through Win95, after about 2Mb, it starts using virtual memory.
: (horrible hard disk accesses..)

Heh. Conclusion: CWSDPMI is a good DPMI host; Windows is a bad one.

: Is there anyway I can disable virtual memory, and just exit the program
: if not enough physical RAM is available?

It's really up to the DPMI host whether you get real or virtual memory,
I think.

: Does anyone know how I can allocate more physical RAM under Win95?  (I
: heard that 'Quake' was written in DJGPP and this manages to allocate
: plenty of RAM through Win95)

See Charles Sandmann's (several) posts to the thread entitled
__djgpp_base_address; he describes (briefly) how id Software do this in
Quake. It seems to be a messy method which he implies is unreliable 
(CMIIW...), so chances are you won't want to do it anyway.

: I have tried fiddling with the Win95 memory properties for rhide.exe,
: and this does not seem to have helped.

Didn't you know they only put those in to give tech support gurus 
something to say when they're stumped? ;)

-- 
George Foot <gfoot AT mc31 DOT merton DOT ox DOT ac DOT uk>
Merton College, Oxford.

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