Red Hat ENTERPRISE LINUX 3 - FOR X86-ITANIUMTM-AMD64 AND INTEL EXTENDED MEMORY 64 TECHNOLO, Installation Manual

Page: 89 / 120

Appendix C. Troubleshooting Your Installation of Red Hat Enterprise Linux 77
C.4.6. Is Your RAM Not Being Recognized?
Sometimes, the kernel does not recognize all of your memory (RAM). You can check this with the
cat /proc/meminfo
command.
Find out if the displayed quantity is the same as the known amount of RAM in your system. If they
are not equal, add the following line to the
/boot/grub/grub.conf
:
mem= xx M
Replace
xx
with the amount of RAM you have in megabytes.
In
/boot/grub/grub.conf
, the above example would look similar to the following:
#NOTICE: You have a /boot partition. This means that
#
all kernel paths are relative to /boot/
default=0
timeout=30
splashimage=(hd0,0)/grub/splash.xpm.gz
title Red Hat Enterprise Linux (2.4.21-1.1931.2.399.ent)
root (hd0,0)
kernel /vmlinuz-2.4.21-1.1931.2.399.ent ro root=/dev/hda3 mem=128M
Once you reboot, the changes made to
grub.conf
will be reflected on your system.
Or, you can add the following line to the
/etc/lilo.conf
file:
append="mem= xx M"
Note, that the
append
command works in both GRUB and LILO.
Replace
xx
with the amount of RAM you have in megabytes. Remember that per-image append
lines completely overwrite the global append line. It might be worth adding this to the per-image
descriptions.
In
/etc/lilo.conf
, the above example would look similar to the following:
boot=/dev/sda
map=/boot/map
install=/boot/boot.b
prompt
timeout=50
image=/boot/vmlinuz-2.4.21-1.1931.2.399.ent
label=linux
root=/dev/sda1
initrd=/boot/initrd-2.4.21-1.1931.2.399.ent.img
read-only
append="mem=128M"
Remember to run
/sbin/lilo -v
after changing
/etc/lilo.conf
.
Note that you can also produce the same effect by actually passing this option when you are specifying
the label/image to use in GRUB or LILO.
Once you have loaded the GRUB boot screen, type
e
for edit. You are presented with a list of items
in the configuration file for the boot label you have selected.
Choose the line that starts with
kernel
and type
e
to edit this boot entry.
At the end of the
kernel
line, add
mem= xx M