Arcboot is the bootloader used on SGI IP22 machines (Indy and Indigo2) and
the SGI IP32 (O2) to boot Linux from an Ext{2,3}-filesystem.

To install arcboot type:

"/usr/sbin/arcboot <name_of_disk>" as root.

where <name_of_disk> is the disk on which arcboot will be installed. To let
this work the disk *must* have an SGI disklabel. Afterwards copy arcboot.conf
into /etc/ and adjust it to your needs.

Arcboot parses the PROM variable OSLoadPartition to find arcboot.conf therefore
/etc/ has to be on the same partition as the kernel.
It boots the label given in OSLoadFilename or on the command line (see below).

If it can't fine the label in arcboot.conf it tries to boot the file 
OSLoadPartition/OSLoadFilename, allowing you to boot any file on an ext2
filesystem by adjusting OSLoadPartition accordingly (this might be helpful if
your freshly installed kernel doesn't boot).

Besides the append="..." line in /etc/arcboot.conf arcboot also appends the
value of the prom variable OSLoadOptions to the kernel's command line. This
allows you to override the arcboot.conf's kernel command line.

If you enter the prom and boot via the "boot" command you can pass additional
parameters to the kernel. E.g.:

boot linux single console=ttyS0 root=/dev/sda2

will boot the label "linux" from arcboot.conf and append to additional
arguments given above. Or

boot /boot/vmlinux single console=ttyS0 root=/dev/sda2

will boot the file with the absolute path OSLoadPartition/boot/vmlinux with the
same arguments as above. Note that OSLoadPartition must be an partition name
as understood by ARCS (like scsi(0)disk(1)rdisk(0)partition(0)).

Note: arcboot can only load ELF kernels. ECOFF is (and will not be) supported.

For tftpbooting please refer to the tip22 package.

 - arcboot is based on the arc-bootloader for SGI visual workstations written
   by Ralf Baechle
 - the e2fslib dir is basically a stripped down verion of e2fsprogs 1.25 as
   found on http://sourceforge.net/projects/e2fsprogs and written by Theodore
   T'so <tytso@thunk.org> compiled with -nopic. 
 - most of the config file parsing is borrowed from delo by Florian Lohoff
   <flo@rfc822.org>. Additional thanks to him for a weekend of input, testing
   & patches.

 -- Guido Guenther <agx@sigxcpu.org>, Sun, 26 Apr 2003 20:29:43 +0100