bsdlabel -- read and write disk pack label
bsdlabel [-A] disk
bsdlabel -w [-An] [-B [-b boot]] [-m machine] disk [type]
bsdlabel -e [-An] [-B [-b boot]] [-m machine] disk
bsdlabel -R [-An] [-B [-b boot]] [-m machine] disk protofile
The bsdlabel utility installs, examines or modifies the BSD label on a
disk partition. In addition, bsdlabel can install bootstrap code.
Disk Device Name [Toc] [Back]
When specifying the device, the /dev/ path prefix may be omitted; the
bsdlabel utility will automatically prepend it.
General Options [Toc] [Back]
The -A option enables processing of the historical parts of the BSD
label. If the option is not given, suitable values are set for these
fields.
The -n stops the bsdlabel program right before the disk would have been
modified, and displays the result instead of writing it.
The -m machine argument instructs bsdlabel to use the layout suitable for
the specified machine.
Reading the Disk Label [Toc] [Back]
To examine the label on a disk drive, use bsdlabel without options:
bsdlabel [-A] [-m machine] disk
disk represents the disk in question, and may be in the form da0 or
/dev/da0. It will display the partition layout.
Writing a Standard Label [Toc] [Back]
To write a standard label, use the form
bsdlabel -w [-An] [-m machine] disk [type]
If the drive type is specified, the entry of that name in the disktab(5)
file is used; otherwise a default layout is used.
Editing an Existing Disk Label [Toc] [Back]
To edit an existing disk label, use the form
bsdlabel -e [-An] [-m machine] disk
This command opens the disk label in the default editor, and when the
editor exits, the label is validated and if OK written to disk.
Restoring a Disk Label From a File [Toc] [Back]
To restore a disk label from a file, use the form
bsdlabel -R [-An] [-m machine] disk protofile
bsdlabel is capable of restoring a disk label that was previously saved
in a file in ASCII format. 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.
Installing Bootstraps [Toc] [Back]
If the -B argument is specified, bootstrap code will be read from the
file /boot/boot and written to the disk. The -b boot argument allows a
different file to be used.
/boot/boot Default boot image.
/etc/disktab Disk description file.
The bsdlabel utility uses an ASCII version of the label when examining,
editing, or restoring a disk label. The format is:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 81920 0 4.2BSD 1024 8192 16
b: 160000 81920 swap
c: 1173930 0 unused 0 0 # "raw" part, don't edit
If the -A option is specified, the format is:
# /dev/da1c:
type: SCSI
disk: da0s1
label:
flags:
bytes/sector: 512
sectors/track: 51
tracks/cylinder: 19
sectors/cylinder: 969
cylinders: 1211
sectors/unit: 1173930
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0 # milliseconds
track-to-track seek: 0 # milliseconds
drivedata: 0
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 81920 0 4.2BSD 1024 8192 16
b: 160000 81920 swap
c: 1173930 0 unused 0 0 # "raw" part, don't edit
Lines starting with a `#' mark are comments.
The partition table can have up to 8 entries. It contains the following
information:
# The partition identifier is a single letter in the range `a' to
`h'. By convention, partition `c' is reserved to describe the
entire disk.
size The size of the partition in sectors, K (kilobytes - 1024), M
(megabytes - 1024*1024), G (gigabytes - 1024*1024*1024), % (percentage
of free space after removing any fixed-size partitions
other than partition `c'), or * (all remaining free space after
fixed-size and percentage partitions). For partition `c', a size
of * indicates the entire disk. Lowercase versions of K, M, and
G are allowed. Size and type should be specifed without any spaces
between them.
Example: 2097152, 1G, 1024M and 1048576K are all the same size
(assuming 512-byte sectors).
offset The offset of the start of the partition from the beginning of
the drive in sectors, or * to have bsdlabel calculate the correct
offset to use (the end of the previous partition plus one, ignoring
partition `c'. For partition `c', * will be interpreted as
an offset of 0.
fstype Describes the purpose of the partition. The example shows all
currently used partition types. For UFS file systems and ccd(4)
partitions, use type 4.2BSD. For Vinum drives, use type vinum.
Other common types are swap and unused. By convention, partition
`c' represents the entire slice and should be of type unused,
though bsdlabel does not enforce this convention. The bsdlabel
utility also knows about a number of other partition types, none
of which are in current use. (See the definitions starting with
FS_UNUSED in <sys/disklabel.h> for more details.)
fsize For 4.2BSD and LFS file systems only, the fragment size.
Defaults to 1024 for partitions smaller than 1GB, 4096 for partitions
1GB or larger.
bsize For 4.2BSD and LFS file systems only, the block size. Defaults
to 8192 for partitions smaller than 1GB, 16384 for partitions 1GB
or larger.
bps/cpg
For 4.2BSD file systems, the number of cylinders in a cylinder
group. For LFS file systems, the segment shift value. Defaults
to 16 for partitions smaller than 1GB, 64 for partitions 1GB or
larger.
bsdlabel da0s1
Display the label for the first slice of the da0 disk, as obtained via
/dev/da0s1.
bsdlabel da0s1 > savedlabel
Save the in-core label for da0s1 into the file savedlabel. This file can
be used with the -R option to restore the label at a later date.
bsdlabel -w /dev/da0s1
Create a label for da0s1.
bsdlabel -e da0s1
Read the label for da0s1, edit it, and install the result.
bsdlabel -e -n da0s1
Read the on-disk label for da0s1, edit it, and display what the new label
would be (in sectors). It does not install the new label either in-core
or on-disk.
bsdlabel -w da0s1
Write a default label on da0s1. Use another bsdlabel -e command to edit
the partitioning and file system information.
bsdlabel -R da0s1 savedlabel
Restore the on-disk and in-core label for da0s1 from information in
savedlabel.
bsdlabel -R -n da0s1 label_layout
Display what the label would be for da0s1 using the partition layout in
label_layout. This is useful for determining how much space would be
alloted for various partitions with a labelling scheme using %-based or *
partition sizes.
bsdlabel -B da0s1
Install a new bootstrap on da0s1. The boot code comes from /boot/boot.
bsdlabel -w -B -b newboot /dev/da0s1
Install a new label and bootstrap. The bootstrap code comes from the
file newboot in the current working directory.
dd if=/dev/zero of=/dev/da0 bs=512 count=32
fdisk -BI da0
dd if=/dev/zero of=/dev/da0s1 bs=512 count=32
bsdlabel -w -B da0s1
bsdlabel -e da0s1
Completely wipe any prior information on the disk, creating a new
bootable disk with a DOS partition table containing one slice, covering
the whole disk. Initialize the label on this slice, then edit it. The
dd(1) commands are optional, but may be necessary for some BIOSes to
properly recognize the disk.
This is an example disk label that uses some of the new partition size
types such as %, M, G, and *, which could be used as a source file for
``bsdlabel -R ad0s1c new_label_file'':
# /dev/ad0s1c:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 400M 0 4.2BSD 4096 16384 75 # (Cyl. 0 - 812*)
b: 1G * swap
c: * * unused
e: 204800 * 4.2BSD
f: 5g * 4.2BSD
g: * * 4.2BSD
ccd(4), geom(4), md(4), disktab(5), boot0cfg(8), fdisk(8)
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.
FreeBSD 5.2.1 March 15, 2003 FreeBSD 5.2.1 [ Back ] |
