Very Computer

by **Rahul Des** » Wed, 02 Aug 1995 04:00:00

I have a Compaq Presario 650 with 20MB of memory installed. Is there
a reason why Linux only recognizes only 16MB. When I built the kernel
I specified "no" to "16MB or lower option".

Thanks,
Rahul

--

regards,

by **DONALD BARN** » Wed, 02 Aug 1995 04:00:00

>I have a Compaq Presario 650 with 20MB of memory installed. Is there
>a reason why Linux only recognizes only 16MB. When I built the kernel
>I specified "no" to "16MB or lower option".

The kernel config only needs to be set for some old 386's that didn't
handle memory quite kosher, it has nothing really to do with todays
machines.

Try entering:

linux mem=20M
at the LILO boot prompt. If that fixes it, you can add:

append = "mem-20M"

to the "image" section of you lilo.conf, then re-run 'lilo'. You should
be able to reboot then and see all 20M every time.

--Donnie

by **roo** » Thu, 03 Aug 1995 04:00:00

: I have a Compaq Presario 650 with 20MB of memory installed. Is there
: a reason why Linux only recognizes only 16MB. When I built the kernel
Yes, because the BIOS will not see it... Linux keeps away from the BIOS
as much as possible but uses it to determine the amount of RAM in a system
as there is not a standard method to determine this.. and having it max at
16 megs (64 megs on some I think..) detected is better than ALWAYS having to
manually specify the amount of RAM 8-).
As someone else said, try
linux mem=20M
at lilo: prompt, and if that works
append "mem=20M" in lilo.conf...
: I specified "no" to "16MB or lower option".

: Thanks,
: Rahul

: --

: regards,

by **Gary Merinste** » Sat, 05 Aug 1995 04:00:00

>: I have a Compaq Presario 650 with 20MB of memory installed. Is there
>: a reason why Linux only recognizes only 16MB. When I built the kernel
> Yes, because the BIOS will not see it... Linux keeps away from the BIOS
>as much as possible but uses it to determine the amount of RAM in a system
>as there is not a standard method to determine this.. and having it max at
>16 megs (64 megs on some I think..) detected is better than ALWAYS having to
>manually specify the amount of RAM 8-).
> As someone else said, try
>linux mem=20M
>at lilo: prompt, and if that works
>append "mem=20M" in lilo.conf...
>: I specified "no" to "16MB or lower option".
>: Thanks,
>: Rahul
>: --
>: regards,

and what do you do if "mem=20M" doesn't work? i have a compaq 66m
(486dx66 eisa) with 48MB ram. on some kernel re-compiles linux sees all
48MB; on the current build (rhs 1.2.8) it only sees 16MB. does anyone
know where in the kernel i can hard-code the avail ram?

--

** hell will freeze over, and eventually, **
** GM151 things will get really interesting..." **

by **Mar** » Mon, 07 Aug 1995 04:00:00

: and what do you do if "mem=20M" doesn't work? i have a compaq 66m
: (486dx66 eisa) with 48MB ram. on some kernel re-compiles linux sees all
: 48MB; on the current build (rhs 1.2.8) it only sees 16MB. does anyone
: know where in the kernel i can hard-code the avail ram?

It's interesting that it works with some kernels and not with others.
One thing that you might want to check is the memory configuration in
EISA NVRAM. It should be set for "linear mode" vs. "Compaq compatible
mode." Linear mode moves the shadow ROM to the top of memory and away
from the 16MB address (which might confuse the kernel).

If you really want to hard-code the end of physical RAM, which probably
won't solve anything if the boot argument doesn't work, look for

memory_end = (1<<20) + (EXT_MEM_K<<10);

in the file /usr/src/linux/arch/i386/kernel/setup.c and change it to

memory_end = 20*1024*1024;

MarkS
--

A bad day sailing beats a great day at work!

Very Computer

Linux only recoginizes up to 16MB of memory

Linux only recoginizes up to 16MB of memory

Linux only recoginizes up to 16MB of memory

Linux only recoginizes up to 16MB of memory

Linux only recoginizes up to 16MB of memory

Linux only recoginizes up to 16MB of memory