1GDISK(8) GPT fdisk Manual GDISK(8)
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6 gdisk - Interactive GUID partition table (GPT) manipulator
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9 gdisk [ -l ] device
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13 GPT fdisk (aka gdisk) is a text-mode menu-driven program for creation
14 and manipulation of partition tables. It will automatically convert an
15 old-style Master Boot Record (MBR) partition table or BSD disklabel
16 stored without an MBR carrier partition to the newer Globally Unique
17 Identifier (GUID) Partition Table (GPT) format, or will load a GUID
18 partition table. When used with the -l command-line option, the program
19 displays the current partition table and then exits.
20 GPT fdisk operates mainly on the GPT headers and partition tables; how‐
22 ever, it can and will generate a fresh protective MBR, when required.
23 (Any boot loader code in the protective MBR will not be disturbed.) If
24 you've created an unusual protective MBR, such as a hybrid MBR created
25 by gptsync or gdisk's own hybrid MBR creation feature, this should not
26 be disturbed by most ordinary actions. Some advanced data recovery op‐
27 tions require you to understand the distinctions between the main and
28 backup data, as well as between the GPT headers and the partition ta‐
29 bles. For information on MBR vs. GPT, as well as GPT terminology and
30 structure, see the extended gdisk documentation at http://www.rods‐
31 books.com/gdisk/ or consult Wikipedia.
32 The gdisk program employs a user interface similar to that of Linux's
34 fdisk, but gdisk modifies GPT partitions. It also has the capability of
35 transforming MBR partitions or BSD disklabels into GPT partitions. Like
36 the original fdisk program, gdisk does not modify disk structures until
37 you explicitly write them to disk, so if you make a mistake, you can
38 exit from the program with the 'q' option to leave your partitions un‐
39 modified.
40 Ordinarily, gdisk operates on disk device files, such as /dev/sda or
42 /dev/hda under Linux, /dev/disk0 under Mac OS X, or /dev/ad0 or
43 /dev/da0 under FreeBSD. The program can also operate on disk image
44 files, which can be either copies of whole disks (made with dd, for in‐
45 stance) or raw disk images used by emulators such as QEMU or VMWare.
46 Note that only raw disk images are supported; gdisk cannot work on com‐
47 pressed or other advanced disk image formats.
48 The MBR partitioning system uses a combination of cylinder/head/sector
50 (CHS) addressing and logical block addressing (LBA). The former is
51 klunky and limiting. GPT drops CHS addressing and uses 64-bit LBA mode
52 exclusively. Thus, GPT data structures, and therefore gdisk, do not
53 need to deal with CHS geometries and all the problems they create.
54 Users of fdisk will note that gdisk lacks the options and limitations
55 associated with CHS geometries.
56 For best results, you should use an OS-specific partition table program
58 whenever possible. For example, you should make Mac OS X partitions
59 with the Mac OS X Disk Utility program and Linux partitions with the
60 Linux gdisk or GNU Parted program.
61 Upon start, gdisk attempts to identify the partition type in use on the
63 disk. If it finds valid GPT data, gdisk will use it. If gdisk finds a
64 valid MBR or BSD disklabel but no GPT data, it will attempt to convert
65 the MBR or disklabel into GPT form. (BSD disklabels are likely to have
66 unusable first and/or final partitions because they overlap with the
67 GPT data structures, though.) GPT fdisk can identify, but not use data
68 in, Apple Partition Map (APM) disks, which are used on 680x0- and Pow‐
69 erPC-based Macintoshes. Upon exiting with the 'w' option, gdisk re‐
70 places the MBR or disklabel with a GPT. This action is potentially dan‐
71 gerous! Your system may become unbootable, and partition type codes may
72 become corrupted if the disk uses unrecognized type codes. Boot prob‐
73 lems are particularly likely if you're multi-booting with any GPT-un‐
74 aware OS. If you mistakenly launch gdisk on an MBR disk, you can safely
75 exit the program without making any changes by using the 'q' option.
76 The MBR-to-GPT conversion will leave at least one gap in the partition
78 numbering if the original MBR used logical partitions. These gaps are
79 harmless, but you can eliminate them by using the 's' option, if you
80 like. (Doing this may require you to update your /etc/fstab file.)
81 When creating a fresh partition table, certain considerations may be in
83 order:
84 * For data (non-boot) disks, and for boot disks used on BIOS-based
87 computers with GRUB as the boot loader, partitions may be cre‐
88 ated in whatever order and in whatever sizes are desired.
89 * Boot disks for EFI-based systems require an EFI System Partition
92 (gdisk internal code 0xEF00) formatted as FAT-32. I recommended
93 making this partition 550 MiB. (Smaller ESPs are common, but
94 some EFIs have flaky FAT drivers that necessitate a larger par‐
95 tition for reliable operation.) Boot-related files are stored
96 here. (Note that GNU Parted identifies such partitions as having
97 the "boot flag" set.)
98 * Some boot loaders for BIOS-based systems make use of a BIOS Boot
101 Partition (gdisk internal code 0xEF02), in which the secondary
102 boot loader is stored, possibly without the benefit of a
103 filesystem. (GRUB2 may optionally use such a partition.) This
104 partition can typically be quite small (roughly 32 to 200 KiB,
105 although 1 MiB is more common in practice), but you should con‐
106 sult your boot loader documentation for details.
107 * If Windows is to boot from a GPT disk, a partition of type Mi‐
110 crosoft Reserved (gdisk internal code 0x0C01) is recommended.
111 This partition should be about 128 MiB in size. It ordinarily
112 follows the EFI System Partition and immediately precedes the
113 Windows data partitions. (Note that old versions of GNU Parted
114 create all FAT partitions as this type, which actually makes the
115 partition unusable for normal file storage in both Windows and
116 Mac OS X.)
117 * Some OSes' GPT utilities create some blank space (typically 128
120 MiB) after each partition. The intent is to enable future disk
121 utilities to use this space. Such free space is not required of
122 GPT disks, but creating it may help in future disk maintenance.
123 You can use GPT fdisk's relative partition positioning option
124 (specifying the starting sector as '+128M', for instance) to
125 simplify creating such gaps.
126
129 -l List the partition table for the specified device and then ex‐
130 its.
131 Most interactions with gdisk occur with its interactive text-mode
133 menus. Three menus exist: the main menu, the recovery & transformation
134 menu, and the experts' menu. The main menu provides the functions that
135 are most likely to be useful for typical partitioning tasks, such as
136 creating and deleting partitions, changing partition type codes, and so
137 on. Specific functions are:
138 b Save partition data to a backup file. You can back up your cur‐
141 rent in-memory partition table to a disk file using this option.
142 The resulting file is a binary file consisting of the protective
143 MBR, the main GPT header, the backup GPT header, and one copy of
144 the partition table, in that order. Note that the backup is of
145 the current in-memory data structures, so if you launch the pro‐
146 gram, make changes, and then use this option, the backup will
147 reflect your changes. Note also that the restore option is on
148 the recovery & transformation menu; the backup option is on the
149 main menu to encourage its use.
150 c Change the GPT name of a partition. This name is encoded as a
154 UTF-16 string, but proper entry and display of anything beyond
155 basic ASCII values requires suitable locale and font support.
156 For the most part, Linux ignores the partition name, but it may
157 be important in some OSes. GPT fdisk sets a default name based
158 on the partition type code. Note that the GPT partition name is
159 different from the filesystem name, which is encoded in the
160 filesystem's data structures.
161 d Delete a partition. This action deletes the entry from the par‐
164 tition table but does not disturb the data within the sectors
165 originally allocated to the partition on the disk. If a corre‐
166 sponding hybrid MBR partition exists, gdisk deletes it, as well,
167 and expands any adjacent 0xEE (EFI GPT) MBR protective partition
168 to fill the new free space.
169 i Show detailed partition information. The summary information
172 produced by the 'p' command necessarily omits many details, such
173 as the partition's unique GUID and the translation of gdisk's
174 internal partition type code to a plain type name. The 'i' op‐
175 tion displays this information for a single partition.
176 l Display a summary of partition types. GPT uses a GUID to iden‐
179 tify partition types for particular OSes and purposes. For ease
180 of data entry, gdisk compresses these into two-byte (four-digit
181 hexadecimal) values that are related to their equivalent MBR
182 codes. Specifically, the MBR code is multiplied by hexadecimal
183 0x0100. For instance, the code for Linux swap space in MBR is
184 0x82, and it's 0x8200 in gdisk. A one-to-one correspondence is
185 impossible, though. Most notably, the codes for all varieties of
186 FAT and NTFS partition correspond to a single GPT code (entered
187 as 0x0700 in gdisk). Some OSes use a single MBR code but employ
188 many more codes in GPT. For these, gdisk adds code numbers se‐
189 quentially, such as 0xa500 for a FreeBSD disklabel, 0xa501 for
190 FreeBSD boot, 0xa502 for FreeBSD swap, and so on. Note that
191 these two-byte codes are unique to gdisk. The type code list may
192 optionally be filtered by a search string; for instance, enter‐
193 ing linux shows only partition type codes with descriptions that
194 include the string Linux. This search is performed case-insensi‐
195 tively.
196 n Create a new partition. This command is modeled after the equiv‐
199 alent fdisk option, although some differences exist. You enter a
200 partition number, starting sector, and an ending sector. Both
201 start and end sectors can be specified in absolute terms as sec‐
202 tor numbers or as positions measured in kibibytes (K), mebibytes
203 (M), gibibytes (G), tebibytes (T), or pebibytes (P); for in‐
204 stance, 40M specifies a position 40MiB from the start of the
205 disk. You can specify locations relative to the start or end of
206 the specified default range by preceding the number by a '+' or
207 '-' symbol, as in +2G to specify a point 2GiB after the default
208 start sector, or -200M to specify a point 200MiB before the last
209 available sector. Pressing the Enter key with no input specifies
210 the default value, which is the start of the largest available
211 block for the start sector and the end of the same block for the
212 end sector. Default start and end points may be adjusted to op‐
213 timize partition alignment.
214 o Clear out all partition data. This includes GPT header data, all
217 partition definitions, and the protective MBR. The sector align‐
218 ment is reset to the default (1 MiB, or 2048 sectors on a disk
219 with 512-byte sectors).
220 p Display basic partition summary data. This includes partition
223 numbers, starting and ending sector numbers, partition sizes,
224 gdisk's partition types codes, and partition names. For addi‐
225 tional information, use the 'i' command.
226 q Quit from the program without saving your changes. Use this op‐
229 tion if you just wanted to view information or if you make a
230 mistake and want to back out of all your changes.
231 r Enter the recovery & transformation menu. This menu includes
234 emergency recovery options (to fix damaged GPT data structures)
235 and options to transform to or from other partitioning systems,
236 including creating hybrid MBRs.
237 s Sort partition entries. GPT partition numbers need not match the
240 order of partitions on the disk. If you want them to match, you
241 can use this option. Note that some partitioning utilities sort
242 partitions whenever they make changes. Such changes will be re‐
243 flected in your device filenames, so you may need to edit
244 /etc/fstab if you use this option.
245 t Change a single partition's type code. You enter the type code
248 using a two-byte hexadecimal number, as described earlier. You
249 may also enter a GUID directly, if you have one and gdisk
250 doesn't know it.
251 v Verify disk. This option checks for a variety of problems, such
254 as incorrect CRCs and mismatched main and backup data. This op‐
255 tion does not automatically correct most problems, though; for
256 that, you must use options on the recovery & transformation
257 menu. If no problems are found, this command displays a summary
258 of unallocated disk space.
259 w Write data. Use this command to save your changes.
262 x Enter the experts' menu. Using this option provides access to
265 features you can use to get into even more trouble than the main
266 menu allows.
267 ? Print the menu. Type this command (or any other unrecognized
269 command) to see a summary of available options.
270 The second gdisk menu is the recovery & transformation menu, which pro‐
273 vides access to data recovery options and features related to the
274 transformation of partitions between partitioning schemes (converting
275 BSD disklabels into GPT partitions or creating hybrid MBRs, for in‐
276 stance). A few options on this menu duplicate functionality on the
277 main menu, for the sake of convenience. The options on this menu are:
278 b Rebuild GPT header from backup. You can use the backup GPT
281 header to rebuild the main GPT header with this option. It's
282 likely to be useful if your main GPT header was damaged or de‐
283 stroyed (say, by sloppy use of dd).
284 c Load backup partition table. Ordinarily, gdisk uses only the
287 main partition table (although the backup's integrity is checked
288 when you launch the program). If the main partition table has
289 been damaged, you can use this option to load the backup from
290 disk and use it instead. Note that this will almost certainly
291 produce no or strange partition entries if you've just converted
292 an MBR disk to GPT format, since there will be no backup parti‐
293 tion table on disk.
294 d Use main GPT header and rebuild the backup. This option is
297 likely to be useful if the backup GPT header has been damaged or
298 destroyed.
299 e Load main partition table. This option reloads the main parti‐
302 tion table from disk. It's only likely to be useful if you've
303 tried to use the backup partition table (via 'c') but it's in
304 worse shape then the main partition table.
305 f Load MBR and build fresh GPT from it. Use this option if your
308 GPT is corrupt or conflicts with the MBR and you want to use the
309 MBR as the basis for a new set of GPT partitions.
310 g Convert GPT into MBR and exit. This option converts as many par‐
313 titions as possible into MBR form, destroys the GPT data struc‐
314 tures, saves the new MBR, and exits. Use this option if you've
315 tried GPT and find that MBR works better for you. Note that
316 this function generates up to four primary MBR partitions or
317 three primary partitions and as many logical partitions as can
318 be generated. Each logical partition requires at least one unal‐
319 located block immediately before its first block. Therefore, it
320 may be possible to convert a maximum of four partitions on disks
321 with tightly-packed partitions; however, if free space was in‐
322 serted between partitions when they were created, and if the
323 disk is under 2 TiB in size, it should be possible to convert
324 all the partitions to MBR form. See also the 'h' option.
325 h Create a hybrid MBR. This is an ugly workaround that enables
328 GPT-unaware OSes, or those that can't boot from a GPT disk, to
329 access up to three of the partitions on the disk by creating MBR
330 entries for them. Note that these hybrid MBR entries can easily
331 go out of sync with the GPT entries, particularly when hy‐
332 brid-unaware GPT utilities are used to edit the disk. Thus, you
333 may need to re-create the hybrid MBR if you use such tools. Un‐
334 like the 'g' option, this option does not support converting any
335 partitions into MBR logical partitions.
336 i Show detailed partition information. This option is identical to
339 the 'i' option on the main menu.
340 l Load partition data from a backup file. This option is the re‐
343 verse of the 'b' option on the main menu. Note that restoring
344 partition data from anything but the original disk is not recom‐
345 mended.
346 m Return to the main menu. This option enables you to enter
349 main-menu commands.
350 o Print protective MBR data. You can see a summary of the protec‐
353 tive MBR's partitions with this option. This may enable you to
354 spot glaring problems or help identify the partitions in a hy‐
355 brid MBR.
356 p Print the partition table. This option is identical to the 'p'
359 option in the main menu.
360 q Quit without saving changes. This option is identical to the 'q'
363 option in the main menu.
364 t Transform BSD partitions into GPT partitions. This option works
367 on BSD disklabels held within GPT (or converted MBR) partitions.
368 Converted partitions' type codes are likely to need manual ad‐
369 justment. gdisk will attempt to convert BSD disklabels stored on
370 the main disk when launched, but this conversion is likely to
371 produce first and/or last partitions that are unusable. The many
372 BSD variants means that the probability of gdisk being unable to
373 convert a BSD disklabel is high compared to the likelihood of
374 problems with an MBR conversion.
375 v Verify disk. This option is identical to the 'v' option in the
378 main menu.
379 w Write table to disk and exit. This option is identical to the
382 'w' option in the main menu.
383 x Enter the experts' menu. This option is identical to the 'x' op‐
386 tion in the main menu.
387 ? Print the menu. This option (or any unrecognized entry) displays
390 a summary of the menu options.
391 The third gdisk menu is the experts' menu. This menu provides advanced
394 options that aren't closely related to recovery or transformation be‐
395 tween partitioning systems. Its options are:
396 a Set attributes. GPT provides a 64-bit attributes field that can
399 be used to set features for each partition. gdisk supports four
400 attributes: system partition, read-only, hidden, and do not au‐
401 tomount. You can set other attributes, but their numbers aren't
402 translated into anything useful. In practice, most OSes seem to
403 ignore these attributes.
404 b Swap the byte order for the name of the specified partition.
407 Some partitioning tools, including GPT fdisk 1.0.7 and earlier,
408 can write the partition name in the wrong byte order on big-en‐
409 dian computers, such as the IBM s390 mainframes and PowerPC-
410 based Macs. This feature corrects this problem.
411 c Change partition GUID. You can enter a custom unique GUID for a
414 partition using this option. (Note this refers to the GUID that
415 uniquely identifies a partition, not to its type code, which you
416 can change with the 't' main-menu option.) Ordinarily, gdisk as‐
417 signs this number randomly; however, you might want to adjust
418 the number manually if you've wound up with the same GUID on two
419 partitions because of buggy GUID assignments (hopefully not in
420 gdisk) or sheer incredible coincidence.
421 d Display the sector alignment value. See the description of the
424 'l' option for more details.
425 e Move backup GPT data structures to the end of the disk. Use this
428 command if you've added disks to a RAID array, thus creating a
429 virtual disk with space that follows the backup GPT data struc‐
430 tures. This command moves the backup GPT data structures to the
431 end of the disk, where they belong.
432 f Randomize the disk's GUID and all partitions' unique GUIDs (but
435 not their partition type code GUIDs). This function may be used
436 after cloning a disk with another utility in order to render all
437 GUIDs once again unique.
438 g Change disk GUID. Each disk has a unique GUID code, which gdisk
441 assigns randomly upon creation of the GPT data structures. You
442 can generate a fresh random GUID or enter one manually with this
443 option.
444 h Recompute CHS values in protective or hybrid MBR. This option
447 can sometimes help if a disk utility, OS, or BIOS doesn't like
448 the CHS values used by the partitions in the protective or hy‐
449 brid MBR. In particular, the GPT specification requires a CHS
450 value of 0xFFFFFF for over-8GiB partitions, but this value is
451 technically illegal by the usual standards. Some BIOSes hang if
452 they encounter this value. This option will recompute a more
453 normal CHS value -- 0xFEFFFF for over-8GiB partitions, enabling
454 these BIOSes to boot.
455 i Show detailed partition information. This option is identical to
458 the 'i' option on the main menu.
459 j Adjust the location of the main partition table. This value is
462 normally 2, but it may need to be increased in some cases, such
463 as when a system-on-chip (SoC) is hard-coded to read boot code
464 from sector 2. I recommend against adjusting this value unless
465 doing so is absolutely necessary.
466 l Change the sector alignment value. Disks with more logical sec‐
469 tors per physical sectors (such as modern Advanced Format
470 drives), some RAID configurations, and many SSD devices, can
471 suffer performance problems if partitions are not aligned prop‐
472 erly for their internal data structures. On new disks, GPT fdisk
473 attempts to align partitions on 1 MiB boundaries (2048 sectors
474 on disks with 512-byte sectors) by default, which optimizes per‐
475 formance for all of these disk types. On pre-partitioned disks,
476 GPT fdisk attempts to identify the alignment value used on that
477 disk, but will set 8-sector alignment on disks larger than 300
478 GB even if lesser alignment values are detected. In either case,
479 it can be changed by using this option. The alignment value
480 also affects the default end sector value when creating a new
481 partition; it will be aligned to one less than a multiple of the
482 alignment value, if possible. This should keep partitions a mul‐
483 tiple of the alignment value in size. Some disk encryption tools
484 require partitions to be sized to some value, typically 4096
485 bytes, so the default alignment of 1 MiB works well for them.
486 m Return to the main menu. This option enables you to enter
489 main-menu commands.
490 n Create a new protective MBR. Use this option if the current pro‐
493 tective MBR is damaged in a way that gdisk doesn't automatically
494 detect and correct, or if you want to convert a hybrid MBR into
495 a "pure" GPT with a conventional protective MBR.
496 o Print protective MBR data. You can see a summary of the protec‐
499 tive MBR's partitions with this option. This may enable you to
500 spot glaring problems or help identify the partitions in a hy‐
501 brid MBR.
502 p Print the partition table. This option is identical to the 'p'
505 option in the main menu.
506 q Quit without saving changes. This option is identical to the 'q'
509 option in the main menu.
510 r Enter the recovery & transformations menu. This option is iden‐
513 tical to the 'r' option on the main menu.
514 s Resize partition table. The default partition table size is 128
517 entries. Officially, sizes of less than 16KB (128 entries,
518 given the normal entry size) are unsupported by the GPT specifi‐
519 cation; however, in practice they seem to work, and can some‐
520 times be useful in converting MBR disks. Larger sizes also work
521 fine. OSes may impose their own limits on the number of parti‐
522 tions, though.
523 t Swap two partitions' entries in the partition table. One parti‐
526 tion may be empty. For instance, if partitions 1-4 are defined,
527 transposing 1 and 5 results in a table with partitions numbered
528 from 2-5. Transposing partitions in this way has no effect on
529 their disk space allocation; it only alters their order in the
530 partition table.
531 u Replicate the current device's partition table on another de‐
534 vice. You will be prompted to type the new device's filename.
535 After the write operation completes, you can continue editing
536 the original device's partition table. Note that the replicated
537 partition table is an exact copy, including all GUIDs; if the
538 device should have its own unique GUIDs, you should use the f
539 option on the new disk.
540 v Verify disk. This option is identical to the 'v' option in the
543 main menu.
544 z Zap (destroy) the GPT data structures and exit. Use this option
547 if you want to repartition a GPT disk using fdisk or some other
548 GPT-unaware program. You'll be given the choice of preserving
549 the existing MBR, in case it's a hybrid MBR with salvageable
550 partitions or if you've already created new MBR partitions and
551 want to erase the remnants of your GPT partitions. If you've al‐
552 ready created new MBR partitions, it's conceivable that this op‐
553 tion will damage the first and/or last MBR partitions! Such an
554 event is unlikely, but could occur if your new MBR partitions
555 overlap the old GPT data structures.
556 ? Print the menu. This option (or any unrecognized entry) displays
559 a summary of the menu options.
560 In many cases, you can press the Enter key to select a default option
563 when entering data. When only one option is possible, gdisk usually by‐
564 passes the prompt entirely.
565
568 Known bugs and limitations include:
569 * The program compiles correctly only on Linux, FreeBSD, Mac OS X,
572 and Windows. Linux versions for x86-64 (64-bit), x86 (32-bit),
573 and PowerPC (32-bit) have been tested, with the x86-64 version
574 having seen the most testing. Under FreeBSD, 32-bit (x86) and
575 64-bit (x86-64) versions have been tested. Only 32-bit versions
576 for Mac OS X and Windows have been tested by the author, al‐
577 though I've heard of 64-bit versions being successfully com‐
578 piled.
579 * The FreeBSD version of the program can't write changes to the
582 partition table to a disk when existing partitions on that disk
583 are mounted. (The same problem exists with many other FreeBSD
584 utilities, such as gpt, fdisk, and dd.) This limitation can be
585 overcome by typing sysctl kern.geom.debugflags=16 at a shell
586 prompt.
587 * The fields used to display the start and end sector numbers for
590 partitions in the 'p' command are 14 characters wide. This
591 translates to a limitation of about 45 PiB. On larger disks, the
592 displayed columns will go out of alignment.
593 * In the Windows version, only ASCII characters are supported in
596 the partition name field. If an existing partition uses
597 non-ASCII UTF-16 characters, they're likely to be corrupted in
598 the 'i' and 'p' menu options' displays; however, they should be
599 preserved when loading and saving partitions. Binaries for
600 Linux, FreeBSD, and OS X support full UTF-16 partition names.
601 * The program can load only up to 128 partitions (4 primary parti‐
604 tions and 124 logical partitions) when converting from MBR for‐
605 mat. This limit can be raised by changing the #define
606 MAX_MBR_PARTS line in the basicmbr.h source code file and recom‐
607 piling; however, such a change will require using a
608 larger-than-normal partition table. (The limit of 128 partitions
609 was chosen because that number equals the 128 partitions sup‐
610 ported by the most common partition table size.)
611 * Converting from MBR format sometimes fails because of insuffi‐
614 cient space at the start or (more commonly) the end of the disk.
615 Resizing the partition table (using the 's' option in the ex‐
616 perts' menu) can sometimes overcome this problem; however, in
617 extreme cases it may be necessary to resize a partition using
618 GNU Parted or a similar tool prior to conversion with gdisk.
619 * MBR conversions work only if the disk has correct LBA partition
622 descriptors. These descriptors should be present on any disk
623 over 8 GiB in size or on smaller disks partitioned with any but
624 very ancient software.
625 * BSD disklabel support can create first and/or last partitions
628 that overlap with the GPT data structures. This can sometimes be
629 compensated by adjusting the partition table size, but in ex‐
630 treme cases the affected partition(s) may need to be deleted.
631 * Because of the highly variable nature of BSD disklabel struc‐
634 tures, conversions from this form may be unreliable -- parti‐
635 tions may be dropped, converted in a way that creates overlaps
636 with other partitions, or converted with incorrect start or end
637 values. Use this feature with caution!
638 * Booting after converting an MBR or BSD disklabel disk is likely
641 to be disrupted. Sometimes re-installing a boot loader will fix
642 the problem, but other times you may need to switch boot load‐
643 ers. Except on EFI-based platforms, Windows through at least
644 Windows 7 doesn't support booting from GPT disks. Creating a hy‐
645 brid MBR (using the 'h' option on the recovery & transformation
646 menu) or abandoning GPT in favor of MBR may be your only options
647 in this case.
648
651 Primary author: Roderick W. Smith (rodsmith@rodsbooks.com)
652 Contributors:
654 * Yves Blusseau (1otnwmz02@sneakemail.com)
656 * David Hubbard (david.c.hubbard@gmail.com)
658 * Justin Maggard (justin.maggard@netgear.com)
660 * Dwight Schauer (das@teegra.net)
662 * Florian Zumbiehl (florz@florz.de)
664
668 cfdisk(8), cgdisk(8), fdisk(8), mkfs(8), parted(8), sfdisk(8),
669 sgdisk(8), fixparts(8).
670 http://en.wikipedia.org/wiki/GUID_Partition_Table
672 http://developer.apple.com/technotes/tn2006/tn2166.html
674 http://www.rodsbooks.com/gdisk/
676
679 The gdisk command is part of the GPT fdisk package and is available
680 from Rod Smith.
681Roderick W. Smith 1.0.9 GDISK(8)