The HP xw9300 workstation requires acpi=off on the kernel command line in the /etc/grub.conf file to properly support a Red Hat Enterprise Linux 4 Update 1 in a single or dual core configuration.

For Red Hat Enterprise Linux 4 Update 2, no kernel line parameters are required.

If you experience a problem with any other dual core system, typically a kernel panic during boot, you may want to try any or all of the following kernel line parameters in the /etc/grub.conf file:

* Red Hat Enterprise Linux 4 Gold:
  - dual core systems not supported

* Red Hat Enterprise Linux 4 Update 1:
  - numa=off
  - acpi=off

* Red Hat Enterprise Linux 4 Update 2 and beyond:
  - pci=noseg
  - pci=nommconf

Note: The above is not applicable to Red Hat Enterprise Linux 3, however, Update 5 is required for dual core support on the xw9300.

If you need to add any of the above options to the grub.conf file, use the following example:

title Red Hat Enterprise Linux AS (2.6.9-11.EL)
        root (hd0,0)
        kernel /vmlinuz-2.6.9-11.EL ro root=LABEL=/ acpi=off console=ttys0
        initrd /initrd-2.6.9-11.EL.img

Multiple kernel line parameters should be separated by a space. You will need to reboot the system in order for the changes to take effect.