gdisk

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
       options require you to understand the distinctions between the main and
       backup data, as well as between  the  GPT  headers  and  the  partition
       tables.  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
       unmodified.

       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
       instance)  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
       replaces the MBR or disklabel with a GPT. This  action  is  potentially
       dangerous!  Your system may become unbootable, and partition type codes
       may become corrupted if the disk uses  unrecognized  type  codes.  Boot
       problems  are  particularly  likely  if  you're  multi-booting with any
       GPT-unaware 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. I recommended
              making this partition 550 MiB. (Smaller  ESPs  are  common,  but
              some  EFIs have flaky FAT drivers that necessitate a larger par-
              tition for reliable operation.) Boot-related  files  are  stored
              here. (Note that GNU Parted identifies 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,
              although  1 MiB is more common in practice), but you should con-
              sult your boot loader documentation for details.

       *      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
              exits.

       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'
              option 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
              sequentially, 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 modeled after the equiv-
              alent 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 sec-
              tor 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  default
              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 (1MB, or 2048 sectors on a disk
              with 512-byte sectors).

       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
              option 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
              reflected 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
              option 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
       instance).  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
              destroyed (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
              inserted 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
              hybrid-unaware  GPT  utilities are used to edit the disk.  Thus,
              you may need to re-create the hybrid MBR if you use such  tools.
              Unlike  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
              reverse 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
              hybrid 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
              adjustment.  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'
              option 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
       between 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
              automount.  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
              assigns  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
              hybrid 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.

       j      Adjust the location of the main partition table. This  value  is
              normally  2, but it may need to be increased in some cases, such
              as when a system-on-chip (SoC) is hard-coded to read  boot  code
              from  sector  2. I recommend against adjusting this value unless
              doing so is absolutely necessary.

       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 1MiB boundaries (2048-sectors on
              disks with 512-byte sectors) by default, which optimizes perfor-
              mance 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
              hybrid 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
              device.  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
              already  created  new MBR partitions, it's conceivable that this
              option 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
       bypasses the prompt entirely.

BUGS
       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,
              although  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
              experts'  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
              extreme 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
              hybrid MBR (using the 'h' option on the recovery  &  transforma-
              tion  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@gmail.com)

       * Florian Zumbiehl (florz@florz.de)

SEE ALSO
       cfdisk (8), cgdisk (8), fdisk (8), mkfs (8),  parted  (8),  sfdisk  (8)
       sgdisk (8) fixparts (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                    1.0.3                            GDISK(8)
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