April 24, 2003

### NAME

pdisk - Apple partition table editor

### SYNOPSIS

pdisk [-acdfhilLrv] [--abbr] [--compute_size] [--debug] [--fname] [--help] [--interactive] [--list device] [--logical] [--readonly] [--version] [device ...]

### DESCRIPTION

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 fdisk(8).

Supported options are:

-a
--abbr
  Abbreviate the partition types shown in the partition list.
-c
--compute_size
  Causes pdisk to always ignore the device size listed in the partition table and compute the device size by other means.
-d
--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 functionality.
-f
--fname
  Show HFS volume names instead of partition name when available.
-h
--help
  Prints a short help message.
-i
--interactive
  Causes pdisk to go into an interactive mode similar to the MacOS version of the program.
-l
--list device
  List the partition tables for the specified devices.
-L
--logical
  Show partition limits in logical blocks. Default is physical blocks.
-r
--readonly
  Prevents pdisk from writing to the device.
-v
--version
  Prints the version number of .

#### 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 confirmation 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 precipitate 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 partition. 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 partition 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 this limitation.

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.

### SEE ALSO

fdisk(8), newfs(8)

### HISTORY

The pdisk utility was originally developed for MkLinux.

### AUTHORS

Eryk Vershen

### BUGS

Some people believe there should really be just one disk partitioning utility.

Filesystem volume names are out of place in a partition utility. This utility supports HFS volume names, but not volume names of any other filesystem types.

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.