From: alaric AT abwillms DOT demon DOT co DOT uk (Alaric B. Williams)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: djgpp DLL's?; The generation gap
Date: Mon, 14 Apr 1997 17:13:31 GMT
Message-ID: <335263da.3899106@news.demon.co.uk>
References: <F385831313 AT fs2 DOT mt DOT umist DOT ac DOT uk>
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

On Mon, 14 Apr 1997 15:41:49 GMT, "Anthony.Appleyard"
<MCLSSAA2 AT fs2 DOT mt DOT umist DOT ac DOT uk> wrote:

>  DPMI swops <heap data> in and out. I was talking about swopping in and out
><program code> which is not used much.

DPMI swaps anything out that isn't locked in RAM (which we sometimes
do for technical reasons, but if you lock your RAM, you'll know it, so
don't worry about that). Code can go to swap disk, too.

A feature found on many UNIX systems that would probably do what you
wanted is called "demand loading", where "loading" and executable
doesn't actually do any "loading". The binary file is put into the
virtual address space as if it was a swap file, but nothing is swapped
in; it's as if the code had been loaded and swapped out. The memory
range is made read only so the binary can't be modified by accident,
and from then on, the code is brought in by the MMU as it is needed...

ABW
--
"Plug and Play support: WfEWAD will autodetect any installed
Nuclear Arsenals, Laser Satellites, Battlefield Control Networks,
Radar Installations, Fighter Squadrons, and other WfEWAD compliant
devices, including the new Macrosoft Unnatural Keyboard, with
full support for the now-famous Big Red Buttom(tm)."

(Windows for Early Warning and Defence User's manual P26)

Alaric B. Williams Internet : alaric AT abwillms DOT demon DOT co DOT uk
<A HREF="http://www.abwillms.demon.co.uk/">Hello :-)</A>