*BSD News Article 34498


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From: bde@kralizec.zeta.org.au (Bruce Evans)
Newsgroups: comp.os.386bsd.misc,comp.os.386bsd.questions
Subject: Re: > 16 megs of ram on FreeBSD 1.1.5
Date: 18 Aug 1994 16:06:55 +1000
Organization: Kralizec Dialup Unix Sydney - +61-2-837-1183, v.32bis v.42bis
Lines: 27
Message-ID: <32utpv$2vd@kralizec.zeta.org.au>
References: <32og7cINNhaj@soccer.cis.ohio-state.edu>
NNTP-Posting-Host: kralizec.zeta.org.au

In article <32og7cINNhaj@soccer.cis.ohio-state.edu>,
joel braden wood <wood@cis.ohio-state.edu> wrote:

>I recompiled the kernel, and nowhere in the configuration file was the
>MAXMEM variable...  So I'm assuming that it isn't in the compile.  But
>FreeBSD still only recognizes 16 out of my 24 megs. At bootup I get the
>following message: (I think this is even before it looks at the kernel)
>
>
>>> FreeBSD BOOT @ 0x90000: 639/15360k of memory   [$ Revision: 1.14 $]
>use hd(1,a)/386bsd to boot sd0 when wd0 is also installed
>Boot: [[[wd(0,a)]/386bsd][-s][-a][-d] :-

This message is from the bootstrap loader.  The BIOS has reported that
there is only 639K of memory starting at 0 and 15360K of high memory
starting at 1M.  The kernel had better find exactly the same amount
of memory as the BIOS reports.  It doesn't use the BIOS (this is a
bug) and probably finds 640K of low memory and 15360K of high memory.

Your missing 8MB of memory is apparently not reported in the standard
way, although the standard way can handle up to 64M of contiguous
high memory.  Perhaps your extra memory is not contiguous.  FreeBSD
can be made to support contiguous missing memory by changing the
initialization of ``biosextmem'' in /sys/i386/i386/machdep.c.  Supporting
discontiguous extra memory is harder.
-- 
Bruce Evans  bde@kralizec.zeta.org.au