Re: mem=64MB oh yes! mem=128MB oh no! (2.0.34pre16)

Rik van Riel (
Fri, 22 May 1998 11:20:19 +0200 (MET DST)

On Fri, 22 May 1998, Lluisma wrote:

> So I modified my lilo.conf with an append statement. Sad to say
> when I rebooted my machine, I got a kernel panic. It says it can't
> mount the root fs. I booted from a floppy, removed the append statement
> in my lilo.conf and run /sbin/lilo. Again, I rebooted my machine, this
> time I specified mem=128MB in the LILO boot prompt. It encountered the
> same problem.

> I restarted the machine. Didn't specify anything at the boot prompt.
> Everything went fine but the kernel only detects 64MB of RAM. Am I
> missing something here? Is there a problem somewhere else?

Well, basically you missed the fact that the BIOS grabs some
memory, leaving less for Linux. Then you tell Linux "go ahead,
use all the memory" and somewhat later Linux discovers that
some of the memory isn't there anymore because the BIOS grabs
it. Unfortunately, the hardware has crashed since then...

The solution is either to specify mem=127M, or mem=xxxxxK
where you have calculated the amount of kilobytes left.
127.5 MB is probably safe, you can usually get 200k more,
but that's not always worth the experimenting.

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