DISKLABEL(8) MachTen Programmer’s Manual DISKLABEL(8)

NAME
disklabel - read and write disk pack label

SYNOPSIS
disklabel [ -r ] disk
disklabel -w [ -r ] disk disktype [ packid [ priboot sec-
boot ] ]
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 bootstrap program. This information is
used by the system disk driver and by the bootstrap pro-
gram to determine how to program the drive. There are
several forms of the command that display, install or mod-
ify 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 parameters 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 incorrect, 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 partitions
are taken from that file. If different disks of the same
physical 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 identifica-
tion string, up to 16 characters long. The pack id must
be quoted if it contains blanks. If the -r flag is given,
the disk sectors containing the label and bootstrap will
be written directly, otherwise 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 standard 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 basename-
boot 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 environ-
ment 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