DISKLABEL(8)DISKLABEL(8)NAMEdisklabel - read and write disk pack label
SYNOPSISdisklabel [ -r ] disk
disklabel-w [ -r ] disk disktype [ packid [ priboot secboot ] ]
disklabel-e [ -r ] disk
disklabel-R [ -r ] disk protofile [ priboot secboot ]
disklabel [ -NW ] disk
DESCRIPTION
Disklabel can be used to install, examine or modify the label on a disk
drive or pack. When writing the label, it can be used to change the
drive identification, the disk partitions on the drive, or to replace a
damaged label or bootstrap. The disk label is located on one of the
first sectors of each disk (usually block 0). On machines that require
a block-0 bootstrap (VAX 11/750), the label is inserted into the boot‐
strap program. This information is used by the system disk driver and
by the bootstrap program to determine how to program the drive. There
are several forms of the command that display, install or modify the
label on a disk. Each form has an additional option, -r, which causes
the label to be read from or written to the disk directly, rather than
going through the system's in-core copy of the label. When writing,
the in-core copy is also updated if possible. This option may allow a
label to be installed on a disk without kernel support for a label,
such as when labels are first installed on a system; it must be used
when first installing a label on a disk.
The first form of the command is used to examine the label on the named
disk drive (e.g. hp0 or /dev/rhp0c). It will display all of the param‐
eters associated with the drive and its partition layout. Unless the
-r flag is given, the kernel's in-core copy of the label is displayed;
if the disk has no label, or the partition types on the disk are incor‐
rect, the kernel may have constructed or modified the label. If the -r
flag is given, the label from the raw disk will be displayed rather
than the in-core label.
The second form of the command, with the -w flag, is used to write a
standard label on the designated drive. The required arguments to
disklabel are the drive to be labelled (e.g. hp0), and the drive type
as described in the disktab(5) file. The drive parameters and parti‐
tions are taken from that file. If different disks of the same physi‐
cal type are to have different partitions, it will be necessary to have
separate disktab entries describing each, or to edit the label after
installation as described below. The first optional argument is a pack
identification string, up to 16 characters long. The pack id must be
quoted if it contains blanks. If the -r flag is given, the disk sec‐
tors containing the label and bootstrap will be written directly, oth‐
erwise the existing label will be updated in place without modifying
the bootstrap. If the disk does not already have a label, the -r flag
must be used. In either case, the kernel's in-core label is replaced.
Alternate versions of the bootstrap files may be specified after the
pack identifier. If an alternate bootstrap is not specified, the stan‐
dard bootstrap will be used. The bootstrap programs are located in
/usr/mdec. The names of the bootstrap programs may be specified in
disktab(5); if not specified, the default names are of the form base‐
nameboot for the primary (block 0) bootstrap, and bootbasename for the
secondary (block 1-15) bootstrap; for example, /usr/mdec/hpboot and
/usr/mdec/boothp if the disk device is hp0.
An existing disk label may be edited by using the -e flag. The label
is read from the in-core kernel copy, or directly from the disk if the
-r flag is also given. The label is formatted and then supplied to an
editor for changes. If no editor is specified in an EDITOR environment
variable, vi(1) is used. When the editor terminates, the formatted
label is reread and used to rewrite the disk label.
With the -R flag, disklabel is capable of restoring a disk label that
was formatted in a prior operation and saved in an ascii file. The
prototype file used to create the label should be in the same format as
that produced when reading or editing a label. Comments are delimited
by # and newline. If the -r option is also given, a block-0 bootstrap
is installed on machines that use one; either the disktype or the names
of the bootstrap files must be specified on such machines.
Finally, the -NW flags for disklabel explicitly disallow and allow,
respectively, writing of the pack label area on the selected disk.
FILES
/etc/disktab
/usr/mdec/xxboot
/usr/mdec/bootxx
SEE ALSOdisktab(5), disklabel(5)DIAGNOSTICS
The kernel device drivers will not allow the size of a disk partition
to be decreased or the offset of a partition to be changed while it is
open. Some device drivers create a label containing only a single
large partition if a disk is unlabeled; thus, the label must be written
to the ``a'' partition of the disk while it is open. This sometimes
requires the desired label to be set in two steps, the first one creat‐
ing at least one other partition, and the second setting the label on
the new partition while shrinking the ``a'' partition.
BUGS
When a disk name is given without a full pathname, the constructed
device name uses the ``c'' partition on the vax and the ``a'' partition
on the tahoe.
4.2 Berkeley Distribution June 24, 1990 DISKLABEL(8)
