78 lines
2.6 KiB
Text
78 lines
2.6 KiB
Text
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Information related to the eliloalt Linux tool
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---------------------------------------------
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(c) 2002-2003 Hewlett Packard Co
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Contributed by Stephane Eranian <eranian@hpl.hp.com>
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Last updated: March 1st, 2002
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The elilo alternate image feature uses an EFI variable called EliloAlt.
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The content of this variable is a UNICODE string containing a kernel
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image file and its command line options. The variable has a NULL GUID.
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To create, read, or modify the variable you need to use the EFI variable
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service and the SetVariable() or GetVariable() interface. The service
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is available when EFI is in boot service mode, i.e., prior to loading
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the kernel but it is also available at runtime when the Linux kernel
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has taken over the control of the machine.
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In order to modify the variable, you can either write a small EFI applications
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or use the Linux/ia64 interface to the EFI variables which use the /proc filesystem.
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The elilalt tool included in this package uses the /proc interface to EFI variables
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to create, read, or modify the EliloAlt variable. This tool is a Linux/ia64 application
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and NOT an EFI application.
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Because modiyfing the EliloAlt can influence how the machine is booted, you must
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be root to run the program, even when you simply want to read the content of
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the variable.
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Eliloalt provides the following options:
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-h, --help display this help and exit
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--version output version information and exit
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-s, --set cmdline set elilo alternate variable to cmdline
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-p, --print print elilo alternate variable
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-d, --delete print elilo alternate variable
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1/ Creation of the variable
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To create the variable you can type:
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# eliloalt -s "vmlinuz-2.4.9 root=/dev/sdb2 hdc=ide-scsi"
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It is VERY important to use quotes to make sure that the entire list of arguments is
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treated as a single argument to the program. Otherwise only the first element
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(here vmlinuz-2.4.9) will be used.
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2/ Printing the content of the variable
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To print the content of the variable you need to type:
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# eliloalt -p
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EliloAlt="vmlinuz-2.4.9 root=/dev/sdb2 hdc=ide-scsi"
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3/ Modifying the variable
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You can simply use the -s option:
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# eliloalt -s "vmlinuz-2.4.18 root=/dev/sdb2"
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# eliloalt -p
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EliloAlt="vmlinuz-2.4.18 root=/dev/sdb2"
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3/ Deleting the variable
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You must use the -d option:
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# eliloalt -p
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EliloAlt="vmlinuz-2.4.18 root=/dev/sdb2"
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# eliloalt -d
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# eliloalt -p
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variable not defined
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Keep in mind that the variable is automatically deleted by elilo if:
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- the checkalt option is specified in the config file
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OR
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- the -a is used on the command line
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