Is Your Ram Not Being Recognized - Red Hat ENTREPRISE LINUX 5 Installation Manual

If you cannot remember your root password, boot your system as linux single.
Itanium users must enter boot commands with elilo followed by the boot command.
If you are using an x86-based system and GRUB is your installed boot loader, type e for edit when the
GRUB boot screen has loaded. 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:
single
Press Enter to exit edit mode.
Once the boot loader screen has returned, type b to boot the system.
Once you have booted into single user mode and have access to the # prompt, you must type passwd
root, which allows you to enter a new password for root. At this point you can type shutdown -r
now to reboot the system with the new root password.
If you cannot remember your user account password, you must become root. To become root, type su
- and enter your root password when prompted. Then, type passwd <username>. This allows you to
enter a new password for the specified user account.
If the graphical login screen does not appear, check your hardware for compatibility issues. The
Hardware Compatibility List can be found at:
http://hardware.redhat.com/hcl/

6.4.6. 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.
Verify that 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=xxM
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 (2.6.9­5.EL)
Is Your RAM Not Being Recognized?
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