Installation guide

Figure 7–1: RZ73 Default Disk Partitions
ZK−0837U−R
a
0
131072
1564781
3907911
h
d
c
e
g
disk partitions
1212416
f
2736346
disk sectors
393216
b
The disk label is located in block 0 (zero) in one of the first sectors of the
disk. The disk label provides detailed information about the geometry of
the disk and the partitions into which the disk is divided. The system disk
driver and the boot program use the disk label information to recognize the
drive, the disk partitions, and the file systems. Other information is used
by the operating system to use the disk most efficiently and to locate
important file system information.
The disk label description of each partition contains an identifier for the
partition type (for example, standard file system, swap space, and so on).
There are two copies of a disk label, one located on the disk and one located
in system memory. Because it is faster to access system memory than to
perform I/O, when a system recognizes a disk, it copies the disk label into
memory. The file system updates the in-memory copy of the label if it
contains incomplete information about the file system. If a disk is not
labeled and does not contain an ULTRIX-style partition table, the
partitions are obtained from the /etc/disktab file. You can change the
Administering the UNIX File System 7–3