Date: Fri, 29 Jul 94 21:40:04 JST
From: Stephen Turnbull <turnbull AT shako DOT sk DOT tsukuba DOT ac DOT jp>
To: watersm1_at_kapiti02 AT kapiti DOT co DOT uk
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: djgpp memory requirements


   From: watersm1_at_kapiti02 AT kapiti DOT co DOT uk

	I have used djgpp to port CVS, RCS and diff to DOS, but to get the 
	programs to run requires 550k of free conventional memory. This I 
	assume is because CVS spawns a chain of programs. For example,
	the cvs update operation spawns:

		   cvs -> rcsmerge -> diff3 -> diff

	Does the above command result in 4 memory resident copies of go32 
	(Even though the rest of the program is swapped out ) ?

Yes, it does, but 570KB is the estimate I would have come up with.
This is historically a problem with recursive makes, as well.

	Does anyone have any ideas for reducing memory requirements ?

Not now, although you could write real mode versions that swap all of
themselves out (eg for cvs).  In version 2.0, there will be no
extender.  Protected mode will be provided via DPMI.  But... some DPMI
hosts (eg, QDPMI) require (reportedly) big (100KB+) buffers down in
conventional memory.  So choose your host well.
    Also, DJ is not yet predicting when there will be a public release
of 2.0.  But there is an ALPHA release in //ftp.cygnus.com/pub/dj, and
you might be able to tweak that into doing the job for you.

+-----------------------------------------------------------------------+
|                           Stephen Turnbull                            |
|     University of Tsukuba, Institute of Socio-Economic Planning       |
|          Tennodai 1-chome 1--1, Tsukuba, Ibaraki 305 JAPAN            |
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|                                                                       |
|                Founder and CEO, Skinny Boy Associates                 |
|               Mechanism Design and Social Engineering                 |
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