Re: memory parameters at booting ? (problem)

Ulrich Windl (
Fri, 15 Mar 1996 08:56:36 +0100

On 14 Mar 96 at 22:56, Alexandre Molari wrote:

> hello,
> I've got a 386sx with 4mb ram and I would like to use it as a 2nd computer
> connected to my main one with plip. The problem is that my ram chip have a
> problem. At a certain address (an unique one) the memory test fails. Therefore
> when I boot the computer my old shitty bios use only my first 2 megs :(
> (the strange thing is that it works well - except the particular memory
> address error - the first time I've booted with these ram configuration).
> I suppose linux uses the information of the bios and therefore it uses only
> 2 megs of ram (then again, the first time I booted my computer with these
> ram chips it worked fine: 4 megs available). Now here are the questions
> 1) Is it possible to force linux at boot time to use all my memory (4 megs)
> and therefore linux shouldn't 'listen' to the bios about it.
> 2) Can I specify the unique address linux should exclude (not use) because
> it's a buggy memory byte in the memory ? Maybe it does that automagically ?
> Thanks very much for any help (linux work _much_ faster with 4mb ram than with
> 2mb, above all on an old 386sx ;-)

I think excluding (mapping out) some physical memory should be
possible (HP-UX 10 can do it on special hardware even while running).
I don't have alpha, but I think I've seen some code to find a bad
memory address.

What about an "exclude=from1-to1,from2,to2" as kernel parameter. It's
a pitty that the i386 hardware does not give the address of faulty
memory. This is working on Sun4 quite nice.

Ulrich Windl Klinikum der Universitaet Regensburg
Rechenzentrum DV-med Franz-Josef-Strauss-Allee 11
Tel: +49 941 944-5879 D-93053 Regensburg
FAX: +49 941 944-5882
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