Appendix H. Additional Boot Options

Boot Time Command Arguments

askmethod

This command asks you to select the installation method you would like to use when booting from the Red Hat Linux CD-ROM.

apic

This command works around a bug commonly encountered in the Intel 440GX chipset BIOS and should only be executed with the installation program kernel.

apm=allow_ints

This command changes how the suspend service is handled (and may be necessary for some laptops).

apm=off

This command disables APM (Advanced Power Management). It useful because some BIOSes have buggy power management (APM) and tend to crash.

apm=power_off

This command makes Red Hat Linux shutdown (power off) the system by default. It is useful for SMP systems that do not shutdown by default.

apm=realmode_power_off

Some BIOSes crash when trying to shutdown (power off) the machine. This command changes the method of how this is done from the Windows NT way to the Windows 95 way.

dd

This argument causes the installation program to prompt you to use a driver diskette.

display=IP:0

This command allows remote display forwarding. In this command, IP should be replaced with the IP address of the system on which you want the display to appear.

On the system you want the display to appear on, you must execute the command xhost +remotehostname, where remotehostname is the name of the host from which you are running the original display. Using the command xhost +remotehostname limits access to the remote display terminal and does not allow access from anyone or any system not specifically authorized for remote access.

driverdisk

This command performs the same function as the dd command and also prompts you to use a driver diskette during the installation of Red Hat Linux.

expert

This command turns on the following special features:

• allows partitioning of removable media

• prompts for driver diskette

ide=nodma

This command disables DMA on all IDE devices and may be useful when having IDE-related problems.

isa

This command prompts you for ISA device configuration.

linux upgradeany

This command relaxes some of the checks on your /etc/redhat-release file. If your /etc/redhat-release file has been changed from the default, your Red Hat Linux installation may not be found when attempting an upgrade to Red Hat Linux 9.

lowres

This command forces the graphical (GUI) installation program to run at a lower resolution (640x480).

mediacheck

This command gives you the option of testing the integrity of the install source (if an ISO-based method). Verifying that the ISO images are intact before you attempt an installation helps to avoid problems that are often encountered during an installation.

mem=xxxM

This command allows you to override the amount of memory the kernel detects for the machine. This may be needed for some older systems where the only 16 MB is detected and for some new machines where the video card shares the video memory with the main memory. When executing this command, xxx should be replaced with the amount of memory in megabytes.

nmi_watchdog=1

This command enables the built-in kernel deadlock detector. This command can be used to debug hard kernel lockups. By executing periodic NMI (Non Maskable Interrupt) interrupts, the kernel can monitor whether any CPU has locked up and print out debugging messages as needed.

noapic

This command tells the kernel not to use the APIC chip. It may be helpful for some motherboards with a bad APIC (such as the Abit BP6) or with a buggy BIOS.

noathlon

This command tells the kernel to disable Athlon optimizations. This command may be helpful where Athlon optimizations are found not to work on certain chipsets.

noht

This command disables hyperthreading (when available in SMP systems).

nomce

This command disables self-diagnosis checks performed on the CPU. The kernel enables self-diagnosis on the CPU by default (called Machine Check Exception). On some older Compaq machines, this check is run too often and may need to be disabled.

nopass

This command disables the passing of keyboard and mouse information to stage 2 of the installation program. It can be used to test keyboard and mouse configuration screens during stage 2 of the installation program when performing a network installation.

nopcmcia

This command ignores any PCMCIA controllers in system.

noprobe

This command disables hardware detection and instead prompts the user for hardware information.

noshell

This command disables shell access on virtual console 2 during an installation.

nousb

This command disables the loading of USB support during the installation. If the installation program tends to hang early in the process, this command may be helpful.

nousbstorage

This command disables the loading of the usbstorage module in the installation program's loader. It may help with device ordering on SCSI systems.

reboot=b

This command changes the way the kernel tries to reboot the machine. If a kernel hang is experienced while the system is shutting down, this command may cause the system to reboot successfully.

rescue

This command runs rescue mode. Refer to the Red Hat Linux Customization Guide for more information about rescue mode.

resolution=

Tells the installation program which video mode to run. It accepts any standard resolution, such as 640x480, 800x600, 1024x768, and so on.

serial

This command turns on serial console support.

skipddc

This command skips the ddc monitor probe which causes problems on some systems.

text

This command disables the graphical installation program and forces the installation program to run in text mode.

updates

This command prompts you to insert a floppy diskette containing updates (bug fixes). It is not needed if you are performing a network installation and have already placed the updates image contents in RHupdates/ on the server.