Dear Amber users --
I recently increased the physical RAM on my Linux box from 1 GB to 2 GB,
hoping that it would enable me to run 'nmode' with a MAXMEMX setting
(in nmode/sizes.h) larger than the value
parameter (MAXMEMX=115000000)
which I could get when I had only 1 GB.
Unfortunately this doesn't seem to be happening -- I get segmentation
faults
when I run 'nmode' compiled with MAXMEMX set above 115000000, just
as I did when I had only 1 GB of RAM.
I gather from
http://amber.ch.ic.ac.uk/Questions/mail/18.html
that 115000000 corresponds to about 1 GB.
Other programs seem to see all the memory. E.g., partial output of the
program 'free' on my system is
total used free
Mem: 2064528 80780 1983748
And the C program below returns
Finished
i = 2097152000
when SIZE = (2000*1024*1024) and
Error: could not allocate buf...exiting
when SIZE = (2024*1024*1024).
Some of the (probably ill-advised) things I've tried, to get 'nmode'
to use all the memory are:
1) running the bash shell command 'ulimit -v nnnnnn'
for various memory nnnnnn settings.
2) recompiling amber or just nmode with various command
line parameters passed to the g77 command.
3) recompiling the (RedHat 8.0) kernel 2.4.18-24.8.0smp
with various values of
CONFIG_*HIGHMEM
CONFIG_HIGHMEM*G
CONFIG_*GB
(Currently the kernel boots up and says
1151MB HIGHMEM available
896MB LOWMEM available
and I've not been able to find parameter
settings that would give me more LOWMEM.)
4) appending a 'mem=nnnnM' line to LILO's lilo.conf
file
Nothing seems to help.
Any suggestions?
-- E. S.
---------------------------------------------------------------
/*
** allocatable memory
**
** modified from:
**
**
http://strasbourg.linuxfr.org/jl3/features-2.3-2.html#ss2.1
*/
#include <stdio.h>
#define SIZE (2000*1024*1024)
main()
{
int i;
char *buf = malloc(SIZE);
if ( !buf )
{
printf("Error: could not allocate buf...exiting\n");
exit(1);
}
i = 0;
for ( ; i < SIZE; i += 4096, buf += 4096)
{
*(int *)buf = 0;
}
printf("Finished\n");
printf("i = %12d \n", i );
}
Received on Thu Feb 27 2003 - 22:53:00 PST
