Re: Ram problems

Hans Lermen (
Tue, 16 Jul 1996 14:26:52 +0200 (MET DST)

On Sun, 14 Jul 1996, Michel LESPINASSE wrote:

> After upgrading my memory from 16 to 32 MB, I had to pass the option
> "mem=32M" to the linux kernel because this additionnal memory wasn't
> [ ... ]
> ... The workaround is simple : we can read the
> information from the CMOS clock instead.

Though we really need some better memory detection, using the CMOS
will only solve the problem for machines < 64M, above this you will get
garbage from the CMOS (worst case) or modulo 64M ( best case).
Hence the problem remains.

As some one on this list already pointed out, we have to use
INT15 AX=E820 or AX=E801, if these are supported by the BIOS.
( and all newer BIOSes do so )
I guess we will start realizing this in 2.1.x (if Linus agrees).

BTW: Loadlin _uses_ the CMOS info and hooks this info into INT15, so
setup.S will get the CMOS values when calling INT15 AH=88.