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From: aswNS@hamp.hampshire.edu (Albert S Woodhull)
Subject: Re: Maxing Memory with Minix?
Message-ID: <c1e7cb$a31d.212@news.hampshire.edu>
Date: Sat, 30 Dec 1995 15:03:29 GMT
References: <DKB0q9.LFr.0.bloor@torfree.net>
Organization: Hampshire College, Amherst MA
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On Thu, 28 Dec 1995 16:06:09 GMT Justin Keswick (aw802@torfree.net)
wrote in comp.os.minix:

> My 286 has 1 Mb or 1024 Kb of RAM.  Using the variables in monitor, what is
> the safest way to maximize the memory?
> 
> If I have 'memsize=640' and 'emssize=384' which should give 1024 Kb it
> loads and does not report 'Memory size = 1024K'.
> If I have 'memsize=640' and 'emssize=438' it shows
> 'Memory size = 1024K'.  What accounts for this inconsistency?
> Is it safe to have 'Memory size = 1024K'?

I don't think Minix is prepared to do anything about changing the memory
allocations it finds when it starts. I think the only thing you can
possibly do is to change the allocations in the CMOS setup, perhaps by
changing whether shadowing is used or not. I don't know if this will be
effective or not. In protected mode Minix can use up to three totally
disjunct chunks of memory -- it will try to put the RAM disk in the
highest one and then will make further memory allocations from whatever is
left. Memory is always going to be disjunct because of the design of the
IBM-compatible machine, with video RAM and device ROM in the area above
640K.  So, except for the fragmentation and the possibilty that some big
programs might not fit because of the fragmentation there is little to be
gained by trying to see the memory as one big chunk. For 16 bit mode
programs can't be very big anyway. 

> Maybe someone could explain memory management under Minix?
> What settings would I need if I upgraded to 4 Mb of RAM?

If you upgrade and the CMOS correctly detects it, Minix will use it.

> Is there such a thing as a memory swap partition or file
> under 16 bit Minix?  Is it possible to implement in the kernel?

... an exercise for the user, perhaps.  Anything is possible. 

> I am still contemplating if MGR Windows is possible under 16 bit Minix?

I don't know about this one, sorry. Standard Minix currently only has 
character-based terminal support (although Minix-386vm does have support 
for X Windows).

Albert S. Woodhull, Hampshire College, Amherst, MA
awoodhull@hamp.hampshire.edu
woodhull@shaysnet.com
413-549-2962



