This chapter explains the procedure that you would use to recover your SGI IRIX operating system disk in case of a complete system failure—when you are left with nothing but bare metal. For suggestions on how to avoid this situation, please read the first section of Chapter 7.
Before discussing bare-metal recovery of an IRIX system, it is
important to discuss the layout of an IRIX system, since it is a
little different from most other flavors of Unix that use
Berkeley (BSD) style
partitioning. At a minimum, an IRIX system disk contains four
partitions. The first partition that contains data is partition 0,
partition 1 is the first swap partition.
Partition 10, the volume, is the whole disk,
overlapping all the other partitions. The very first partition
physically on a system disk is partition 8, the volume header. It starts at block
and contains the system disk parameters, partition table, and volume
directory as well as any programs that are necessary for booting,
such as sash, the standalone shell.
sash is required to be in the volume header of the
system disk; we talk more about sash later in this
section. Some system disks will have an additional partition for
/usr, which is partition 6. System disks that
have XFS filesystems with external XLV log
partitions also have an additional partition, number 15, called the
partition. This could be used with a
separate /usr partition since the root partition cannot have an external ...