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From: grandi@noao.UUCP (Steve Grandi)
Newsgroups: net.unix-wizards
Subject: Increasing Maximum Data Size of a 4.2BSD Process
Message-ID: <404@carina.noao.UUCP>
Date: Mon, 7-Jan-85 15:59:53 EST
Article-I.D.: carina.404
Posted: Mon Jan  7 15:59:53 1985
Date-Received: Tue, 8-Jan-85 04:08:24 EST
Organization: Natl. Optical Astronomy Observatories, Tucson, AZ USA
Lines: 20

I've been asked to modify our 4.2 kernel to allow programs with data
sizes larger than 6 Mb.  

Looking through my news archives, I find that a "cheap" solution is to 
increase the value of DMMAX in /sys/vax/autoconf.c from 1024 to 2048 
(giving approximately 11 Mb of data space) or 4096 (giving approximately 
20Mb).  The side effect of this change is much larger fragmentation of the 
swap area (but we are already swapping on three disks...).  To do the
job "more cleanly" requires increasing the size of the "per-process" structure
(sys/h/user.h) which requires increasing UPAGES which requires
recompiling a lot of programs. (YUK).

I have also deduced that one has to change the value of MAXDSIZ in
/sys/vax/vmparam.h.

Is that all there is to it?  What have I overlooked?
-- 
Steve Grandi, National Optical Astronomy Observatories, Tucson, AZ, 602-325-9228
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