NAME
disklabel
- read and write disk pack label
SYNOPSIS
disklabel
[-ACDFrtv]
disk
disklabel
-e
[-CDFIrv]
disk
disklabel
-i
[-DFIrv]
disk
disklabel
-R
[-DFrv]
disk protofile
disklabel
-w
[-DFrv]
[-f disktab]
disk disktype
packid[.blm Pp]
disklabel
[-NW]
disk
disklabel
-l
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.
The
-e, i, l, R, w, N,
and
-W
options determine the basic operation.
If none are specified the label
is displayed.
- -e
-
Edit the existing label (using
EDITOR
)
and write it back to the disk.
If
EDITOR
is undefined, then
vi(1)
is used.
- -i
-
Interactively update the existing label and write it back to the disk.
- -l
-
Show all known file system types (those that can be specified along a
partition within the label) and exit.
- -R
-
Write (restore) a label by reading it from
protofile.
The file should be in the same format as the default output.
- -w
-
Write a standard label for the specified
disktype.
See
disktab(5).
- -N
-
Disallow writes to the disk sector that contains the label.
This is the default state.
- -W
-
Allow writes to the disk sector that contains the label.
This state may not persist if no programs have the disk open.
The majority of the rest of the options affect more than one form of the
command:
- -A
-
Read all labels from the disk, including ones deleted with
disklabel
-D.
Implies
-r.
- -C
-
Output the partition offset and size values in
<cylinder/head/sector>
format.
Note this format is always accepted on input with either the
-e
or
-R
flags.
- -D
-
Delete all existing labels (by 1's complementing the magic number) before
writing any labels to their default location.
Implies
-r.
If
-D
is specified without a request to write the label, then existing labels are
just deleted.
- -F
-
Treat
disk
as a regular file.
This suppresses all
ioctl(2)
calls, and is the default if
disk
is a regular file.
disk
is always opened using
opendisk(3)
even if
-F
is specified.
Implies
-r.
- -I
-
If a label cannot be read from
disk
request the default one from the kernel.
Implies
-r.
- -f disktab
-
Specify the name of a file to use instead of
/etc/disktab
.
- -r
-
Read/write the disk directly rather than using
ioctl(2)
requests on the kernel.
When writing a label, the kernel will be told about the label before the
label is written and asked to write afterwards.
This is the historic behaviour and can be supressed by specifying
-F.
- -t
-
Format the output as a
disktab(5)
entry.
- -v
-
Be verbose about the operations being done, in particular the disk sectors
being read and written.
Specifying
-v
more than once will increase the verbosity.
On systems that expect to have disks with MBR partitions (see
fdisk(8))
disklabel
will find, and update if requested, labels in the first 8k of type 169
(NetBSD)
MBR labels and within the first 8k of the physical disk.
On other systems
disklabel
will only look at the start of the disk.
The offset at which the labels are written is also system dependent.
disklabel
will detect byteswapped labels, but currently cannot display them.
Previous versions of
disklabel
could update the bootstrap code on some architectures.
This functionality has been subsumed by
installboot(8).
EXIT STATUS
The exit status of
disklabel
is set to indicate any errors or warnings.
The values used are:
- 0
-
The
disklabel
utility has completed successfully.
- 1
-
A fatal error has occurred, such as unknown options passed on the
command line, or writing the disklabel failed.
- 4
-
An I/O error of some sort occurred.
- 101..n
-
One or more warnings occured while reading the disklabel.
Subtract 100 to get the number of warnings detected.
FILES
/etc/disktab
-
EXAMPLES
disklabel sd0
Display the in-core label for sd0 as obtained via
/dev/rsd0c
.
disklabel -w -r /dev/rsd0c sd2212 foo
Create a label for sd0 based on information for
``sd2212''
found in
/etc/disktab
,
using
foo
as the disk pack label.
If you do not have an entry for your disk in
/etc/disktab
,
you can use this style to put
an initial label onto a new disk.
Then dump the label to a file (using
disklabel sd0 > protofile),
editing the file, and replacing the label with
disklabel -R sd0 protofile.
disklabel -e -r sd0
Read the on-disk label for sd0, edit it and reinstall in-core as well
as on-disk.
disklabel -e -I sd0
As previous, but don't fail if there was no label on the disk yet;
provide some default values instead.
disklabel -i -I sd0
As previous, only use the built-in interactive editor.
disklabel -R sd0 mylabel
Restore the on-disk and in-core label for sd0 from information in
mylabel
.
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 creating at least one other partition,
and the second setting the label on the new partition
while shrinking the
``a''
partition.
SEE ALSO
opendisk(3),
disklabel(5),
disktab(5),
dkctl(8),
fdisk(8),
installboot(8),
mbrlabel(8),
mscdlabel(8)
BUGS
If the disk partition is not specified in the disk name
(i.e.,
xy0
instead of
/dev/rxy0c),
disklabel
will construct the full pathname of the disk and use the
``d''
partition on i386, hpcmips, or arc, and the
``c''
partition on all others.
On the sparc, sparc64, sun2, and sun3
NetBSD
systems, the size of each partition must be a multiple of the number
of sectors per cylinder (i.e., each partition must be an integer
number of cylinders), or the boot ROMs will declare the label
invalid and fail to boot the system.
In addition, the
-r
option should never be used on a sparc, sparc64, sun2, or sun3 system
boot disk - the
NetBSD
kernel translates the
NetBSD
disk label into a SunOS compatible format (which is required by the
boot PROMs) when it writes the label.
Using the
-r
flag causes
disklabel
to write directly to disk, and bypass the format translation.
This will result in a disk label that the PROMs will not recognize,
and that therefore cannot be booted from.