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GDISK(8)		       GPT fdisk Manual			      GDISK(8)

NAME
       gdisk - Interactive GUID	partition table	(GPT) manipulator

SYNOPSIS
       gdisk [ -l ] device

DESCRIPTION
       GPT  fdisk  (aka	gdisk) is a text-mode menu-driven program for creation
       and manipulation	of partition tables. It	will automatically convert  an
       old-style  Master  Boot	Record	(MBR) partition	table or BSD disklabel
       stored without an MBR carrier partition to the  newer  Globally	Unique
       Identifier  (GUID)  Partition  Table  (GPT) format, or will load	a GUID
       partition table.	When used with the -l command-line option, the program
       displays	the current partition table and	then exits.

       GPT fdisk operates mainly on the	GPT headers and	partition tables; how-
       ever, it	can and	will generate a	fresh protective MBR,  when  required.
       (Any  boot loader code in the protective	MBR will not be	disturbed.) If
       you've created an unusual protective MBR, such as a hybrid MBR  created
       by  gptsync or gdisk's own hybrid MBR creation feature, this should not
       be disturbed by most ordinary actions. Some advanced data recovery  op-
       tions  require  you to understand the distinctions between the main and
       backup data, as well as between the GPT headers and the	partition  ta-
       bles.  For  information	on MBR vs. GPT,	as well	as GPT terminology and
       structure, see the extended  gdisk  documentation  at  http://www.rods-
       books.com/gdisk/	or consult Wikipedia.

       The  gdisk  program employs a user interface similar to that of Linux's
       fdisk, but gdisk	modifies GPT partitions. It also has the capability of
       transforming MBR	partitions or BSD disklabels into GPT partitions. Like
       the original fdisk program, gdisk does not modify disk structures until
       you  explicitly	write  them to disk, so	if you make a mistake, you can
       exit from the program with the 'q' option to leave your partitions  un-
       modified.

       Ordinarily,  gdisk  operates  on	disk device files, such	as /dev/sda or
       /dev/hda	under Linux,  /dev/disk0  under	 Mac  OS  X,  or  /dev/ad0  or
       /dev/da0	 under	FreeBSD.  The  program	can also operate on disk image
       files, which can	be either copies of whole disks	(made with dd, for in-
       stance)	or  raw	 disk images used by emulators such as QEMU or VMWare.
       Note that only raw disk images are supported; gdisk cannot work on com-
       pressed or other	advanced disk image formats.

       The  MBR	partitioning system uses a combination of cylinder/head/sector
       (CHS) addressing	and logical block  addressing  (LBA).  The  former  is
       klunky  and limiting. GPT drops CHS addressing and uses 64-bit LBA mode
       exclusively. Thus, GPT data structures, and  therefore  gdisk,  do  not
       need  to	 deal  with  CHS  geometries and all the problems they create.
       Users of	fdisk will note	that gdisk lacks the options  and  limitations
       associated with CHS geometries.

       For best	results, you should use	an OS-specific partition table program
       whenever	possible. For example, you should make	Mac  OS	 X  partitions
       with  the  Mac  OS X Disk Utility program and Linux partitions with the
       Linux gdisk or GNU Parted program.

       Upon start, gdisk attempts to identify the partition type in use	on the
       disk.  If  it finds valid GPT data, gdisk will use it. If gdisk finds a
       valid MBR or BSD	disklabel but no GPT data, it will attempt to  convert
       the  MBR	or disklabel into GPT form. (BSD disklabels are	likely to have
       unusable	first and/or final partitions because they  overlap  with  the
       GPT  data structures, though.) GPT fdisk	can identify, but not use data
       in, Apple Partition Map (APM) disks, which are used on 680x0- and  Pow-
       erPC-based  Macintoshes.	 Upon  exiting	with the 'w' option, gdisk re-
       places the MBR or disklabel with	a GPT. This action is potentially dan-
       gerous! Your system may become unbootable, and partition	type codes may
       become corrupted	if the disk uses unrecognized type codes.  Boot	 prob-
       lems  are  particularly likely if you're	multi-booting with any GPT-un-
       aware OS. If you	mistakenly launch gdisk	on an MBR disk,	you can	safely
       exit the	program	without	making any changes by using the	'q' option.

       The  MBR-to-GPT conversion will leave at	least one gap in the partition
       numbering if the	original MBR used logical partitions. These  gaps  are
       harmless,  but  you  can	eliminate them by using	the 's'	option,	if you
       like.  (Doing this may require you to update your /etc/fstab file.)

       When creating a fresh partition table, certain considerations may be in
       order:

       *      For data (non-boot) disks, and for boot disks used on BIOS-based
	      computers	with GRUB as the boot loader, partitions may  be  cre-
	      ated in whatever order and in whatever sizes are desired.

       *      Boot disks for EFI-based systems require an EFI System Partition
	      (gdisk internal code 0xEF00) formatted as	 FAT-32.   The	recom-
	      mended  size  of	this  partition	 is  between  100 and 300 MiB.
	      Boot-related files are stored here. (Note	that GNU Parted	 iden-
	      tifies such partitions as	having the "boot flag" set.)

       *      Some boot	loaders	for BIOS-based systems make use	of a BIOS Boot
	      Partition	(gdisk internal	code 0xEF02), in which	the  secondary
	      boot  loader  is	stored,	 possibly  without  the	 benefit  of a
	      filesystem. (GRUB2 may optionally	use such  a  partition.)  This
	      partition	 can typically be quite	small (roughly 32 to 200 KiB),
	      but you should consult your boot loader  documentation  for  de-
	      tails.

       *      If  Windows  is to boot from a GPT disk, a partition of type Mi-
	      crosoft Reserved (gdisk internal code  0x0C01)  is  recommended.
	      This  partition  should  be about	128 MiB	in size. It ordinarily
	      follows the EFI System Partition and  immediately	 precedes  the
	      Windows  data  partitions. (Note that old	versions of GNU	Parted
	      create all FAT partitions	as this	type, which actually makes the
	      partition	 unusable  for normal file storage in both Windows and
	      Mac OS X.)

       *      Some OSes' GPT utilities create some blank space (typically  128
	      MiB)  after  each	partition. The intent is to enable future disk
	      utilities	to use this space. Such	free space is not required  of
	      GPT  disks, but creating it may help in future disk maintenance.
	      You can use GPT fdisk's relative	partition  positioning	option
	      (specifying  the	starting  sector  as '+128M', for instance) to
	      simplify creating	such gaps.

OPTIONS
       -l     List the partition table for the specified device	and  then  ex-
	      its.

       Most  interactions  with	 gdisk	occur  with  its interactive text-mode
       menus. Three menus exist: the main menu,	the recovery &	transformation
       menu,  and the experts' menu. The main menu provides the	functions that
       are most	likely to be useful for	typical	partitioning  tasks,  such  as
       creating	and deleting partitions, changing partition type codes,	and so
       on. Specific functions are:

       b      Save partition data to a backup file. You	can back up your  cur-
	      rent in-memory partition table to	a disk file using this option.
	      The resulting file is a binary file consisting of	the protective
	      MBR, the main GPT	header,	the backup GPT header, and one copy of
	      the partition table, in that order. Note that the	backup	is  of
	      the current in-memory data structures, so	if you launch the pro-
	      gram, make changes, and then use this option,  the  backup  will
	      reflect  your  changes.  Note also that the restore option is on
	      the recovery & transformation menu; the backup option is on  the
	      main menu	to encourage its use.

       c      Change  the  GPT	name of	a partition. This name is encoded as a
	      UTF-16 string, but proper	entry and display of  anything	beyond
	      basic  ASCII  values  requires suitable locale and font support.
	      For the most part, Linux ignores the partition name, but it  may
	      be  important  in	some OSes. GPT fdisk sets a default name based
	      on the partition type code. Note that the	GPT partition name  is
	      different	 from  the  filesystem	name,  which is	encoded	in the
	      filesystem's data	structures.

       d      Delete a partition. This action deletes the entry	from the  par-
	      tition  table  but  does not disturb the data within the sectors
	      originally allocated to the partition on the disk. If  a	corre-
	      sponding hybrid MBR partition exists, gdisk deletes it, as well,
	      and expands any adjacent 0xEE (EFI GPT) MBR protective partition
	      to fill the new free space.

       i      Show  detailed  partition	 information.  The summary information
	      produced by the 'p' command necessarily omits many details, such
	      as  the  partition's  unique GUID	and the	translation of gdisk's
	      internal partition type code to a	plain type name. The  'i'  op-
	      tion displays this information for a single partition.

       l      Display  a  summary of partition types. GPT uses a GUID to iden-
	      tify partition types for particular OSes and purposes. For  ease
	      of  data entry, gdisk compresses these into two-byte (four-digit
	      hexadecimal) values that are related  to	their  equivalent  MBR
	      codes.  Specifically,  the MBR code is multiplied	by hexadecimal
	      0x0100. For instance, the	code for Linux swap space  in  MBR  is
	      0x82,  and  it's 0x8200 in gdisk.	A one-to-one correspondence is
	      impossible, though. Most notably,	the codes for all varieties of
	      FAT  and NTFS partition correspond to a single GPT code (entered
	      as 0x0700	in sgdisk). Some OSes use a single MBR code but	employ
	      many  more  codes	in GPT.	For these, gdisk adds code numbers se-
	      quentially, such as 0xa500 for a FreeBSD disklabel,  0xa501  for
	      FreeBSD  boot,  0xa502  for  FreeBSD  swap, and so on. Note that
	      these two-byte codes are unique to gdisk.

       n      Create a new partition.  This  command  is  modelled  after  the
	      equivalent  fdisk	 option,  although some	differences exist. You
	      enter a partition	number,	starting sector, and an	ending sector.
	      Both start and end sectors can be	specified in absolute terms as
	      sector numbers  or  as  positions	 measured  in  kibibytes  (K),
	      mebibytes	 (M),  gibibytes (G), tebibytes	(T), or	pebibytes (P);
	      for instance, 40M	specifies a position 40MiB from	the  start  of
	      the disk.	You can	specify	locations relative to the start	or end
	      of the specified default range by	preceding the number by	a  '+'
	      or  '-'  symbol, as in +2G to specify a point 2GiB after the de-
	      fault start sector, or -200M to specify a	 point	200MiB	before
	      the  last	available sector. Pressing the Enter key with no input
	      specifies	the default value, which is the	start of  the  largest
	      available	 block	for  the  start	sector and the end of the same
	      block for	the end	sector.

       o      Clear out	all partition data. This includes GPT header data, all
	      partition	definitions, and the protective	MBR. The sector	align-
	      ment is reset to the default (2048 sectors, or 1MB).

       p      Display basic partition summary data.  This  includes  partition
	      numbers,	starting  and  ending sector numbers, partition	sizes,
	      gdisk's partition	types codes, and partition  names.  For	 addi-
	      tional information, use the 'i' command.

       q      Quit from	the program without saving your	changes.  Use this op-
	      tion if you just wanted to view information or  if  you  make  a
	      mistake and want to back out of all your changes.

       r      Enter  the  recovery  &  transformation menu. This menu includes
	      emergency	recovery options (to fix damaged GPT data  structures)
	      and  options to transform	to or from other partitioning systems,
	      including	creating hybrid	MBRs.

       s      Sort partition entries. GPT partition numbers need not match the
	      order  of	partitions on the disk.	If you want them to match, you
	      can use this option.  Note that some partitioning	utilities sort
	      partitions  whenever they	make changes. Such changes will	be re-
	      flected in your device  filenames,  so  you  may	need  to  edit
	      /etc/fstab if you	use this option.

       t      Change  a	 single	partition's type code. You enter the type code
	      using a two-byte hexadecimal number, as described	 earlier.  You
	      may  also	 enter	a  GUID	 directly,  if	you have one and gdisk
	      doesn't know it.

       v      Verify disk. This	option checks for a variety of problems,  such
	      as  incorrect CRCs and mismatched	main and backup	data. This op-
	      tion does	not automatically correct most problems,  though;  for
	      that,  you  must	use  options  on the recovery &	transformation
	      menu. If no problems are found, this command displays a  summary
	      of unallocated disk space.

       w      Write data. Use this command to save your	changes.

       x      Enter  the  experts'  menu. Using	this option provides access to
	      features you can use to get into even more trouble than the main
	      menu allows.

       ?      Print  the  menu.	 Type  this command (or	any other unrecognized
	      command) to see a	summary	of available options.

       The second gdisk	menu is	the recovery & transformation menu, which pro-
       vides  access  to  data	recovery  options  and features	related	to the
       transformation of partitions between partitioning  schemes  (converting
       BSD  disklabels	into  GPT  partitions or creating hybrid MBRs, for in-
       stance).	 A few options on this menu  duplicate	functionality  on  the
       main menu, for the sake of convenience. The options on this menu	are:

       b      Rebuild  GPT  header  from  backup.  You	can use	the backup GPT
	      header to	rebuild	the main GPT header  with  this	 option.  It's
	      likely  to  be useful if your main GPT header was	damaged	or de-
	      stroyed (say, by sloppy use of dd).

       c      Load backup partition table. Ordinarily,	gdisk  uses  only  the
	      main partition table (although the backup's integrity is checked
	      when you launch the program). If the main	 partition  table  has
	      been  damaged,  you  can use this	option to load the backup from
	      disk and use it instead. Note that this  will  almost  certainly
	      produce no or strange partition entries if you've	just converted
	      an MBR disk to GPT format, since there will be no	backup	parti-
	      tion table on disk.

       d      Use  main	 GPT  header  and  rebuild  the	backup.	This option is
	      likely to	be useful if the backup	GPT header has been damaged or
	      destroyed.

       e      Load  main  partition table. This	option reloads the main	parti-
	      tion table from disk. It's only likely to	be  useful  if	you've
	      tried  to	 use  the backup partition table (via 'c') but it's in
	      worse shape then the main	partition table.

       f      Load MBR and build fresh GPT from	it. Use	this  option  if  your
	      GPT is corrupt or	conflicts with the MBR and you want to use the
	      MBR as the basis for a new set of	GPT partitions.

       g      Convert GPT into MBR and exit. This option converts as many par-
	      titions  as possible into	MBR form, destroys the GPT data	struc-
	      tures, saves the new MBR,	and exits.  Use	this option if	you've
	      tried  GPT  and  find  that MBR works better for you.  Note that
	      this function generates up to four  primary  MBR	partitions  or
	      three  primary  partitions and as	many logical partitions	as can
	      be generated. Each logical partition requires at least one unal-
	      located  block immediately before	its first block. Therefore, it
	      may be possible to convert a maximum of four partitions on disks
	      with  tightly-packed  partitions;	however, if free space was in-
	      serted between partitions	when they were	created,  and  if  the
	      disk  is	under  2 TiB in	size, it should	be possible to convert
	      all the partitions to MBR	form.  See also	the 'h'	option.

       h      Create a hybrid MBR. This	is an  ugly  workaround	 that  enables
	      GPT-unaware  OSes,  or those that	can't boot from	a GPT disk, to
	      access up	to three of the	partitions on the disk by creating MBR
	      entries  for them. Note that these hybrid	MBR entries can	easily
	      go out of	sync with  the	GPT  entries,  particularly  when  hy-
	      brid-unaware GPT utilities are used to edit the disk.  Thus, you
	      may need to re-create the	hybrid MBR if you use such tools.  Un-
	      like the 'g' option, this	option does not	support	converting any
	      partitions into MBR logical partitions.

       i      Show detailed partition information. This	option is identical to
	      the 'i' option on	the main menu.

       l      Load  partition  data from a backup file.	This option is the re-
	      verse of the 'b' option on the main menu.	 Note  that  restoring
	      partition	data from anything but the original disk is not	recom-
	      mended.

       m      Return to	the main  menu.	 This  option  enables	you  to	 enter
	      main-menu	commands.

       o      Print  protective	MBR data. You can see a	summary	of the protec-
	      tive MBR's partitions with this option. This may enable  you  to
	      spot  glaring  problems or help identify the partitions in a hy-
	      brid MBR.

       p      Print the	partition table. This option is	identical to  the  'p'
	      option in	the main menu.

       q      Quit without saving changes. This	option is identical to the 'q'
	      option in	the main menu.

       t      Transform	BSD partitions into GPT	partitions. This option	 works
	      on BSD disklabels	held within GPT	(or converted MBR) partitions.
	      Converted	partitions' type codes are likely to need  manual  ad-
	      justment.	gdisk will attempt to convert BSD disklabels stored on
	      the main disk when launched, but this conversion	is  likely  to
	      produce first and/or last	partitions that	are unusable. The many
	      BSD variants means that the probability of gdisk being unable to
	      convert  a  BSD  disklabel is high compared to the likelihood of
	      problems with an MBR conversion.

       v      Verify disk. This	option is identical to the 'v' option  in  the
	      main menu.

       w      Write  table  to	disk and exit. This option is identical	to the
	      'w' option in the	main menu.

       x      Enter the	experts' menu. This option is identical	to the 'x' op-
	      tion in the main menu.

       ?      Print the	menu. This option (or any unrecognized entry) displays
	      a	summary	of the menu options.

       The third gdisk menu is the experts' menu. This menu provides  advanced
       options	that  aren't closely related to	recovery or transformation be-
       tween partitioning systems. Its options are:

       a      Set attributes. GPT provides a 64-bit attributes field that  can
	      be  used to set features for each	partition. gdisk supports four
	      attributes: system partition, read-only, hidden, and do not  au-
	      tomount.	You can	set other attributes, but their	numbers	aren't
	      translated into anything useful. In practice, most OSes seem  to
	      ignore these attributes.

       c      Change  partition	GUID. You can enter a custom unique GUID for a
	      partition	using this option. (Note this refers to	the GUID  that
	      uniquely identifies a partition, not to its type code, which you
	      can change with the 't' main-menu	option.) Ordinarily, gdisk as-
	      signs  this  number  randomly; however, you might	want to	adjust
	      the number manually if you've wound up with the same GUID	on two
	      partitions  because  of buggy GUID assignments (hopefully	not in
	      gdisk) or	sheer incredible coincidence.

       d      Display the sector alignment value. See the description  of  the
	      'l' option for more details.

       e      Move backup GPT data structures to the end of the	disk. Use this
	      command if you've	added disks to a RAID array, thus  creating  a
	      virtual  disk with space that follows the	backup GPT data	struc-
	      tures. This command moves	the backup GPT data structures to  the
	      end of the disk, where they belong.

       f      Randomize	 the disk's GUID and all partitions' unique GUIDs (but
	      not their	partition type code GUIDs). This function may be  used
	      after cloning a disk with	another	utility	in order to render all
	      GUIDs once again unique.

       g      Change disk GUID.	Each disk has a	unique GUID code, which	 gdisk
	      assigns  randomly	 upon creation of the GPT data structures. You
	      can generate a fresh random GUID or enter	one manually with this
	      option.

       h      Recompute	 CHS  values  in protective or hybrid MBR. This	option
	      can sometimes help if a disk utility, OS,	or BIOS	 doesn't  like
	      the  CHS	values used by the partitions in the protective	or hy-
	      brid MBR.	In particular, the GPT specification  requires	a  CHS
	      value  of	 0xFFFFFF  for over-8GiB partitions, but this value is
	      technically illegal by the usual standards. Some BIOSes hang  if
	      they  encounter  this  value.  This option will recompute	a more
	      normal CHS value -- 0xFEFFFF for over-8GiB partitions,  enabling
	      these BIOSes to boot.

       i      Show detailed partition information. This	option is identical to
	      the 'i' option on	the main menu.

       l      Change the sector	alignment value. Disks with more logical  sec-
	      tors  per	 physical  sectors  (such  as  modern  Advanced	Format
	      drives), some RAID configurations, and  many  SSD	 devices,  can
	      suffer  performance problems if partitions are not aligned prop-
	      erly for their internal data structures. On new disks, GPT fdisk
	      attempts to align	partitions on 2048-sector (1MiB) boundaries by
	      default, which optimizes	performance  for  all  of  these  disk
	      types.  On pre-partitioned disks,	GPT fdisk attempts to identify
	      the alignment value used on that disk,  but  will	 set  8-sector
	      alignment	 on  disks larger than 300 GB even if lesser alignment
	      values are detected. In either case, it can be changed by	 using
	      this option.

       m      Return  to  the  main  menu.  This  option  enables you to enter
	      main-menu	commands.

       n      Create a new protective MBR. Use this option if the current pro-
	      tective MBR is damaged in	a way that gdisk doesn't automatically
	      detect and correct, or if	you want to convert a hybrid MBR  into
	      a	"pure" GPT with	a conventional protective MBR.

       o      Print  protective	MBR data. You can see a	summary	of the protec-
	      tive MBR's partitions with this option. This may enable  you  to
	      spot  glaring  problems or help identify the partitions in a hy-
	      brid MBR.

       p      Print the	partition table. This option is	identical to  the  'p'
	      option in	the main menu.

       q      Quit without saving changes. This	option is identical to the 'q'
	      option in	the main menu.

       r      Enter the	recovery & transformations menu. This option is	 iden-
	      tical to the 'r' option on the main menu.

       s      Resize  partition	table. The default partition table size	is 128
	      entries.	Officially, sizes of  less  than  16KB	(128  entries,
	      given the	normal entry size) are unsupported by the GPT specifi-
	      cation; however, in practice they	seem to	work,  and  can	 some-
	      times  be	useful in converting MBR disks.	Larger sizes also work
	      fine. OSes may impose their own limits on	the number  of	parti-
	      tions, though.

       t      Swap  two	partitions' entries in the partition table. One	parti-
	      tion may be empty. For instance, if partitions 1-4 are  defined,
	      transposing  1 and 5 results in a	table with partitions numbered
	      from 2-5.	Transposing partitions in this way has	no  effect  on
	      their  disk  space allocation; it	only alters their order	in the
	      partition	table.

       u      Replicate	the current device's partition table  on  another  de-
	      vice.  You  will	be prompted to type the	new device's filename.
	      After the	write operation	completes, you	can  continue  editing
	      the original device's partition table.  Note that	the replicated
	      partition	table is an exact copy,	including all  GUIDs;  if  the
	      device  should  have  its	own unique GUIDs, you should use the f
	      option on	the new	disk.

       v      Verify disk. This	option is identical to the 'v' option  in  the
	      main menu.

       z      Zap  (destroy) the GPT data structures and exit. Use this	option
	      if you want to repartition a GPT disk using fdisk	or some	 other
	      GPT-unaware  program.   You'll be	given the choice of preserving
	      the existing MBR,	in case	it's a	hybrid	MBR  with  salvageable
	      partitions  or  if you've	already	created	new MBR	partitions and
	      want to erase the	remnants of your GPT partitions. If you've al-
	      ready created new	MBR partitions,	it's conceivable that this op-
	      tion will	damage the first and/or	last MBR partitions!  Such  an
	      event  is	 unlikely,  but	could occur if your new	MBR partitions
	      overlap the old GPT data structures.

       ?      Print the	menu. This option (or any unrecognized entry) displays
	      a	summary	of the menu options.

       In  many	 cases,	you can	press the Enter	key to select a	default	option
       when entering data. When	only one option	is possible, gdisk usually by-
       passes the prompt entirely.

BUGS
       As  of  March  2014  (version  0.8.10), gdisk should be considered beta
       software. Known bugs and	limitations include:

       *      The program compiles correctly only on Linux, FreeBSD, Mac OS X,
	      and  Windows.  Linux versions for	x86-64 (64-bit), x86 (32-bit),
	      and PowerPC (32-bit) have	been tested, with the  x86-64  version
	      having  seen  the	 most testing. Under FreeBSD, 32-bit (x86) and
	      64-bit (x86-64) versions have been tested. Only 32-bit  versions
	      for  Mac	OS  X  and Windows have	been tested by the author, al-
	      though I've heard	of 64-bit  versions  being  successfully  com-
	      piled.

       *      The  FreeBSD  version  of	the program can't write	changes	to the
	      partition	table to a disk	when existing partitions on that  disk
	      are  mounted.  (The  same	problem	exists with many other FreeBSD
	      utilities, such as gpt, fdisk, and dd.) This limitation  can  be
	      overcome	by  typing  sysctl  kern.geom.debugflags=16 at a shell
	      prompt.

       *      The fields used to display the start and end sector numbers  for
	      partitions  in  the  'p'	command	 are  14 characters wide. This
	      translates to a limitation of about 45 PiB. On larger disks, the
	      displayed	columns	will go	out of alignment.

       *      In  the  Windows version,	only ASCII characters are supported in
	      the  partition  name  field.  If	an  existing  partition	  uses
	      non-ASCII	 UTF-16	 characters, they're likely to be corrupted in
	      the 'i' and 'p' menu options' displays; however, they should  be
	      preserved	 when  loading	and  saving  partitions.  Binaries for
	      Linux, FreeBSD, and OS X support full UTF-16 partition names.

       *      The program can load only	up to 128 partitions (4	primary	parti-
	      tions  and 124 logical partitions) when converting from MBR for-
	      mat.  This  limit	 can  be  raised  by  changing	 the   #define
	      MAX_MBR_PARTS line in the	basicmbr.h source code file and	recom-
	      piling;  however,	 such  a   change   will   require   using   a
	      larger-than-normal partition table. (The limit of	128 partitions
	      was chosen because that number equals the	 128  partitions  sup-
	      ported by	the most common	partition table	size.)

       *      Converting  from	MBR format sometimes fails because of insuffi-
	      cient space at the start or (more	commonly) the end of the disk.
	      Resizing	the  partition	table (using the 's' option in the ex-
	      perts' menu) can sometimes overcome this	problem;  however,  in
	      extreme  cases  it  may be necessary to resize a partition using
	      GNU Parted or a similar tool prior to conversion with gdisk.

       *      MBR conversions work only	if the disk has	correct	LBA  partition
	      descriptors.  These  descriptors	should	be present on any disk
	      over 8 GiB in size or on smaller disks partitioned with any  but
	      very ancient software.

       *      BSD  disklabel  support  can create first	and/or last partitions
	      that overlap with	the GPT	data structures. This can sometimes be
	      compensated  by  adjusting  the partition	table size, but	in ex-
	      treme cases the affected partition(s) may	need to	be deleted.

       *      Because of the highly variable nature of	BSD  disklabel	struc-
	      tures,  conversions  from	 this form may be unreliable --	parti-
	      tions may	be dropped, converted in a way that  creates  overlaps
	      with  other partitions, or converted with	incorrect start	or end
	      values. Use this feature with caution!

       *      Booting after converting an MBR or BSD disklabel disk is	likely
	      to  be disrupted.	Sometimes re-installing	a boot loader will fix
	      the problem, but other times you may need	to switch  boot	 load-
	      ers.  Except  on	EFI-based  platforms, Windows through at least
	      Windows 7	doesn't	support	booting	from GPT disks.	Creating a hy-
	      brid  MBR	(using the 'h' option on the recovery &	transformation
	      menu) or abandoning GPT in favor of MBR may be your only options
	      in this case.

AUTHORS
       Primary author: Roderick	W. Smith (rodsmith@rodsbooks.com)

       Contributors:

       * Yves Blusseau (1otnwmz02@sneakemail.com)

       * David Hubbard (david.c.hubbard@gmail.com)

       * Justin	Maggard	(justin.maggard@netgear.com)

       * Dwight	Schauer	(dschauer@ti.com)

       * Florian Zumbiehl (florz@florz.de)

SEE ALSO
       bsdlabel(8),   cgdisk(8),   fdisk(8),  fixparts(8),  gpart(8),  gpt(8),
       newfs(8), sgdisk(8)

       http://en.wikipedia.org/wiki/GUID_Partition_Table

       http://developer.apple.com/technotes/tn2006/tn2166.html

       http://www.rodsbooks.com/gdisk/

AVAILABILITY
       The gdisk command is part of the	GPT fdisk  package  and	 is  available
       from Rod	Smith.

Roderick W. Smith		    0.8.10			      GDISK(8)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | BUGS | AUTHORS | SEE ALSO | AVAILABILITY

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