Re: Max. Physical Memory Amount

Kurt Garloff (K.Garloff@ping.de)
Sat, 16 Jan 1999 10:22:05 +0100

On Fri, Jan 15, 1999 at 11:57:32AM +0100, Dr. Michael Weller wrote:
> Now, my question is: Is there a very good reason for this (I can see you
> might not get 4G of physical memory for some reasons, but I'd have
> expected at least 3G to work.) ?
>
> I checked the source, and it appears to be a simple sanity check in
> head.c. Can I savely remove it, what is the highest memory amount I can
> hope to work w/o a crash?

No. The kernel implements a 1GB/3GB phys.mem./virt.mem. split. Max. phys.
mem. supported is 960MB, this way.

> I noticed the decent development kernels handel this different. It seems
> they would go almost up to 4GB. Is that right?

No. But you can read linux/include/asm-i386/page.h from a 2.1/2.2 kernel and
do the changes to this file and linux/arch/i386/vmlinux.lds and recompile
your kernel to support more phys. mem. However, the virtual mem, a process
can use, will shrink. My kernel runs happily with 0x70000000 ...

Regards,

-- 
Kurt Garloff <kurt@garloff.de>                           [Dortmund, FRG]  
Plasma physics, high perf. computing              [Linux-ix86,-axp, DUX]
PGP key on http://www.garloff.de/kurt/        [Linux SCSI driver: DC390]


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