PDISK(8) BSD System Manager's Manual PDISK(8)
pdisk -- Apple partition table editor
pdisk [-acdfhilLrv] [--abbr] [--compute_size] [--debug] [--fname]
[--help] [--interactive] [--list device] [--logical] [--readonly]
[--version] [device ...]
pdisk is a menu driven program which partitions disks using the standard
Apple disk partitioning scheme described in "Inside Macintosh: Devices".
It does not support the Intel/DOS partitioning scheme supported by
Supported options are:
--abbr Abbreviate the partition types shown in the partition
--compute_size Causes pdisk to always ignore the device size listed in
the partition table and compute the device size by
--debug Turns on debugging. Doesn't add that much output, but
does add a new command 'x' to the editing commands that
accesses an eclectic bunch of undocumented functional-
--fname Show HFS volume names instead of partition name when
--help Prints a short help message.
--interactive Causes pdisk to go into an interactive mode similar to
the MacOS version of the program.
--list device List the partition tables for the specified devices.
--logical Show partition limits in logical blocks. Default is
--readonly Prevents pdisk from writing to the device.
--version Prints the version number of pdisk.
Editing Partition Tables
An argument which is simply the name of a device indicates that pdisk
should edit the partition table of that device.
The current top level editing commands are:
C (create with type also specified)
c create new partition
d delete a partition
h command help
i initialize partition map
n (re)name a partition
P (print ordered by base address)
p print the partition table
q quit editing (don't save changes)
r reorder partition entry in map
s change size of partition map
t change the type of an existing partition
w write the partition table
Commands which take arguments prompt for each argument in turn. You can
also type any number of the arguments separated by spaces and those
prompts will be skipped. The only exception to typeahead are the confir-
mation prompts on the i and w commands, since if we expect you to confirm
the decision, we shouldn't undermine that by allowing you to be precipi-
tate about it.
Partitions are always specified by their number, which is the index of
the partition entry in the partition map. Most of the commands will
change the index numbers of all partitions after the affected partition.
You are advised to print the table as frequently as necessary.
The c (create new partition) command is the only one with complicated
arguments. The first argument is the base address (in blocks) of the
partition. Besides a raw number, you can also specify a partition number
followed by the letter 'p' to indicate that the first block of the new
partition should be the same as the first block of that existing free
space partition. The second argument is the length of the partition in
blocks. This can be a raw number or can be a partition number followed
by the letter 'p' to use the size of that partition or can be a number
followed by 'k', 'm', or 'g' to indicate the size in kilobytes,
megabytes, or gigabytes respectively. (These are powers of 1024, of
course, not powers of 1000.) The third argument is the name of the par-
tition. This can be a single word without quotes, or a string surrounded
by single or double quotes. The type of the created partition will be
Apple_UNIX_SVR2, which is the correct type for use with NetBSD. This
command will prompt for the unix filesystem slice to set in the Block
Zero Block bits.
The C command is similar to the c command, with the addition of a parti-
tion type argument after the other arguments. Choosing a type of
Apple_UNIX_SVR2 will prompt for the unix filesystem slice to set in the
Block Zero Block bits.
The i (initalize) command prompts for the size of the device.
The n (name) command allows the name of a partition to be changed. Note
that the various "Apple_Driver" partitions depend on the name field for
proper functioning. We are not aware of any other partition types with
The r (reorder) command allows the index number of partitions to be
changed. The index numbers are constrained to be a contiguous sequence.
The t (change partition type) command allows the type of a partition to
be changed. Changing the type to Apple_UNIX_SVR2 will prompt for the
unix filesystem slice to set in the Block Zero Block bits.
The w (write) command writes the partition map out. In order to use the
new partition map you must reboot.
The pdisk utility was originally developed for MkLinux.
Some people believe there should really be just one disk partitioning
Filesystem volume names are out of place in a partition utility. This
utility supports HFS volume names, but not volume names of any other
The --logical option has not been heavily tested.
pdisk will first try to use lseek(2) with SEEK_END to compute the size of
the device. If this fails, it will try a binary search using lseek(2)
and read(2) to find the end of the device. This has been observed to
fail on some raw disk devices. As a workaround, try using the block
device instead. pdisk should probably read the disklabel using the
DIOCGDINFO ioctl(2) to get the device size instead.
BSD April 24, 2003 BSD