[Up] [Map] [Eryk's home page] (Feedback)


pdisk - Apple partition table editor for Linux


pdisk [-h|--help]

pdisk [-i|--interactive]

pdisk [-l|--list [name ...]]

pdisk device ...

pdisk [-v|--version] [-r|--readonly] [-abbr] [--logical] [-c|--compute_size]


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. The device is usually one of the following:


In standard Linux /dev/sda is the first hard disk on the SCSI bus (i.e. the one with the lowest id), /dev/sdb is the second hard disk, and so on. The partition is a device name followed by a partition number. The partition number is the index (starting from one) of the partition map entry in the partition map. For example, /dev/sda2 is the partition described by the second entry in the partiton map on /dev/sda.


-v | --version
Prints version number of the pdisk program.
-h | --help
Prints a rather lame set of help messages for thepdisk program.
-i | --interactive
Causes pdisk to go into an interactive mode similar to the MacOS version of the program.
-l | --list
If no names are present then lists the partition tables for /dev/sda, /dev/sdb, etc., /dev/hda, /dev/hdb, etc., and /dev/scd0, /dev/scd1, etc.. Otherwise, lists the partition tables for the specified names.
-r | --readonly
Prevents pdisk from writing to the device.
-c | --compute_size
Causes pdisk to always ignore the device size listed in the partition table and compute the device size by other means.

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:

	h command help
	p print the partition table
	P (print ordered by base address)
	i initialize partition map
	s change size of partition map
	c create new partition (standard MkLinux type)
	C (create with type also specified)
	n (re)name a partition
	d delete a partition
	r reorder partition entry in map
	w write the partition table
	q quit editing (don't save changes)

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. The idea being that 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 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.

Creating more than fifteen partitions is not advised. There is currently a bug in the some (all?) of the kernels which causes access to the whole disk fail if more than fifteen partitions are in the map.

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 last 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 is the correct type for MkLinux.

The C command is identical to the c command, with the addition of a partition type argument after the other arguments.

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. I am 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 i (initalize) command prompts for the size of the device. This was done to get around a bug in the kernel where it reports the wrong size for the device.

The w (write) command does write the partition map out, but there is currently a bug in the interaction between MkLinux and Mach which causes the partition map not to be reinterpreted. In order to use the new partition map you must reboot.


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

pdisk should be able to create HFS partitions that work.

Even more help should be available during user input.


fdisk(8), mkswap(8), mkfs(8)


Eryk Vershen <eryk@cfcl.com>

Last Updated: 2000-04-18