1GDISK(8) GPT fdisk Manual GDISK(8)
2
3
4
6 gdisk - Interactive GUID partition table (GPT) manipulator
7
9 gdisk [ -l ] device
10
11
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
21 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
27 options require you to understand the distinctions between the main and
28 backup data, as well as between the GPT headers and the partition
29 tables. 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
33 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
39 unmodified.
40
41 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
45 instance) 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
49 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
57 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
62 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
70 replaces the MBR or disklabel with a GPT. This action is potentially
71 dangerous! Your system may become unbootable, and partition type codes
72 may become corrupted if the disk uses unrecognized type codes. Boot
73 problems are particularly likely if you're multi-booting with any
74 GPT-unaware OS. If you mistakenly launch gdisk on an MBR disk, you can
75 safely exit the program without making any changes by using the 'q'
76 option.
77
78 The MBR-to-GPT conversion will leave at least one gap in the partition
79 numbering if the original MBR used logical partitions. These gaps are
80 harmless, but you can eliminate them by using the 's' option, if you
81 like. (Doing this may require you to update your /etc/fstab file.)
82
83 When creating a fresh partition table, certain considerations may be in
84 order:
85
86
87 * For data (non-boot) disks, and for boot disks used on BIOS-based
88 computers with GRUB as the boot loader, partitions may be cre‐
89 ated in whatever order and in whatever sizes are desired.
90
91
92 * Boot disks for EFI-based systems require an EFI System Partition
93 (gdisk internal code 0xEF00) formatted as FAT-32. I recommended
94 making this partition 550 MiB. (Smaller ESPs are common, but
95 some EFIs have flaky FAT drivers that necessitate a larger par‐
96 tition for reliable operation.) Boot-related files are stored
97 here. (Note that GNU Parted identifies such partitions as having
98 the "boot flag" set.)
99
100
101 * Some boot loaders for BIOS-based systems make use of a BIOS Boot
102 Partition (gdisk internal code 0xEF02), in which the secondary
103 boot loader is stored, possibly without the benefit of a
104 filesystem. (GRUB2 may optionally use such a partition.) This
105 partition can typically be quite small (roughly 32 to 200 KiB,
106 although 1 MiB is more common in practice), but you should con‐
107 sult your boot loader documentation for details.
108
109
110 * If Windows is to boot from a GPT disk, a partition of type Mi‐
111 crosoft Reserved (gdisk internal code 0x0C01) is recommended.
112 This partition should be about 128 MiB in size. It ordinarily
113 follows the EFI System Partition and immediately precedes the
114 Windows data partitions. (Note that old versions of GNU Parted
115 create all FAT partitions as this type, which actually makes the
116 partition unusable for normal file storage in both Windows and
117 Mac OS X.)
118
119
120 * Some OSes' GPT utilities create some blank space (typically 128
121 MiB) after each partition. The intent is to enable future disk
122 utilities to use this space. Such free space is not required of
123 GPT disks, but creating it may help in future disk maintenance.
124 You can use GPT fdisk's relative partition positioning option
125 (specifying the starting sector as '+128M', for instance) to
126 simplify creating such gaps.
127
128
130 -l List the partition table for the specified device and then
131 exits.
132
133 Most interactions with gdisk occur with its interactive text-mode
134 menus. Three menus exist: the main menu, the recovery & transformation
135 menu, and the experts' menu. The main menu provides the functions that
136 are most likely to be useful for typical partitioning tasks, such as
137 creating and deleting partitions, changing partition type codes, and so
138 on. Specific functions are:
139
140
141 b Save partition data to a backup file. You can back up your cur‐
142 rent in-memory partition table to a disk file using this option.
143 The resulting file is a binary file consisting of the protective
144 MBR, the main GPT header, the backup GPT header, and one copy of
145 the partition table, in that order. Note that the backup is of
146 the current in-memory data structures, so if you launch the pro‐
147 gram, make changes, and then use this option, the backup will
148 reflect your changes. Note also that the restore option is on
149 the recovery & transformation menu; the backup option is on the
150 main menu to encourage its use.
151
152
153
154 c Change the GPT name of a partition. This name is encoded as a
155 UTF-16 string, but proper entry and display of anything beyond
156 basic ASCII values requires suitable locale and font support.
157 For the most part, Linux ignores the partition name, but it may
158 be important in some OSes. GPT fdisk sets a default name based
159 on the partition type code. Note that the GPT partition name is
160 different from the filesystem name, which is encoded in the
161 filesystem's data structures.
162
163
164 d Delete a partition. This action deletes the entry from the par‐
165 tition table but does not disturb the data within the sectors
166 originally allocated to the partition on the disk. If a corre‐
167 sponding hybrid MBR partition exists, gdisk deletes it, as well,
168 and expands any adjacent 0xEE (EFI GPT) MBR protective partition
169 to fill the new free space.
170
171
172 i Show detailed partition information. The summary information
173 produced by the 'p' command necessarily omits many details, such
174 as the partition's unique GUID and the translation of gdisk's
175 internal partition type code to a plain type name. The 'i'
176 option displays this information for a single partition.
177
178
179 l Display a summary of partition types. GPT uses a GUID to iden‐
180 tify partition types for particular OSes and purposes. For ease
181 of data entry, gdisk compresses these into two-byte (four-digit
182 hexadecimal) values that are related to their equivalent MBR
183 codes. Specifically, the MBR code is multiplied by hexadecimal
184 0x0100. For instance, the code for Linux swap space in MBR is
185 0x82, and it's 0x8200 in gdisk. A one-to-one correspondence is
186 impossible, though. Most notably, the codes for all varieties of
187 FAT and NTFS partition correspond to a single GPT code (entered
188 as 0x0700 in gdisk). Some OSes use a single MBR code but employ
189 many more codes in GPT. For these, gdisk adds code numbers
190 sequentially, such as 0xa500 for a FreeBSD disklabel, 0xa501 for
191 FreeBSD boot, 0xa502 for FreeBSD swap, and so on. Note that
192 these two-byte codes are unique to gdisk. The type code list may
193 optionally be filtered by a search string; for instance, enter‐
194 ing Linux shows only partition type codes with descriptions that
195 include the string Linux. This search is performed case-sensi‐
196 tively.
197
198
199 n Create a new partition. This command is modeled after the equiv‐
200 alent fdisk option, although some differences exist. You enter a
201 partition number, starting sector, and an ending sector. Both
202 start and end sectors can be specified in absolute terms as sec‐
203 tor numbers or as positions measured in kibibytes (K), mebibytes
204 (M), gibibytes (G), tebibytes (T), or pebibytes (P); for
205 instance, 40M specifies a position 40MiB from the start of the
206 disk. You can specify locations relative to the start or end of
207 the specified default range by preceding the number by a '+' or
208 '-' symbol, as in +2G to specify a point 2GiB after the default
209 start sector, or -200M to specify a point 200MiB before the last
210 available sector. Pressing the Enter key with no input specifies
211 the default value, which is the start of the largest available
212 block for the start sector and the end of the same block for the
213 end sector.
214
215
216 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 (1MB, or 2048 sectors on a disk
219 with 512-byte sectors).
220
221
222 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
227
228 q Quit from the program without saving your changes. Use this
229 option if you just wanted to view information or if you make a
230 mistake and want to back out of all your changes.
231
232
233 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
238
239 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
243 reflected in your device filenames, so you may need to edit
244 /etc/fstab if you use this option.
245
246
247 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
252
253 v Verify disk. This option checks for a variety of problems, such
254 as incorrect CRCs and mismatched main and backup data. This
255 option 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
260
261 w Write data. Use this command to save your changes.
262
263
264 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
268 ? Print the menu. Type this command (or any other unrecognized
269 command) to see a summary of available options.
270
271
272 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
276 instance). 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
279
280 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
283 destroyed (say, by sloppy use of dd).
284
285
286 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
295
296 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
300
301 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
306
307 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
311
312 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
322 inserted 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
326
327 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
332 hybrid-unaware GPT utilities are used to edit the disk. Thus,
333 you may need to re-create the hybrid MBR if you use such tools.
334 Unlike the 'g' option, this option does not support converting
335 any partitions into MBR logical partitions.
336
337
338 i Show detailed partition information. This option is identical to
339 the 'i' option on the main menu.
340
341
342 l Load partition data from a backup file. This option is the
343 reverse 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
347
348 m Return to the main menu. This option enables you to enter
349 main-menu commands.
350
351
352 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
355 hybrid MBR.
356
357
358 p Print the partition table. This option is identical to the 'p'
359 option in the main menu.
360
361
362 q Quit without saving changes. This option is identical to the 'q'
363 option in the main menu.
364
365
366 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
369 adjustment. gdisk will attempt to convert BSD disklabels stored
370 on 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
376
377 v Verify disk. This option is identical to the 'v' option in the
378 main menu.
379
380
381 w Write table to disk and exit. This option is identical to the
382 'w' option in the main menu.
383
384
385 x Enter the experts' menu. This option is identical to the 'x'
386 option in the main menu.
387
388
389 ? Print the menu. This option (or any unrecognized entry) displays
390 a summary of the menu options.
391
392
393 The third gdisk menu is the experts' menu. This menu provides advanced
394 options that aren't closely related to recovery or transformation
395 between partitioning systems. Its options are:
396
397
398 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
401 automount. You can set other attributes, but their numbers
402 aren't translated into anything useful. In practice, most OSes
403 seem to ignore these attributes.
404
405
406 c Change partition GUID. You can enter a custom unique GUID for a
407 partition using this option. (Note this refers to the GUID that
408 uniquely identifies a partition, not to its type code, which you
409 can change with the 't' main-menu option.) Ordinarily, gdisk
410 assigns this number randomly; however, you might want to adjust
411 the number manually if you've wound up with the same GUID on two
412 partitions because of buggy GUID assignments (hopefully not in
413 gdisk) or sheer incredible coincidence.
414
415
416 d Display the sector alignment value. See the description of the
417 'l' option for more details.
418
419
420 e Move backup GPT data structures to the end of the disk. Use this
421 command if you've added disks to a RAID array, thus creating a
422 virtual disk with space that follows the backup GPT data struc‐
423 tures. This command moves the backup GPT data structures to the
424 end of the disk, where they belong.
425
426
427 f Randomize the disk's GUID and all partitions' unique GUIDs (but
428 not their partition type code GUIDs). This function may be used
429 after cloning a disk with another utility in order to render all
430 GUIDs once again unique.
431
432
433 g Change disk GUID. Each disk has a unique GUID code, which gdisk
434 assigns randomly upon creation of the GPT data structures. You
435 can generate a fresh random GUID or enter one manually with this
436 option.
437
438
439 h Recompute CHS values in protective or hybrid MBR. This option
440 can sometimes help if a disk utility, OS, or BIOS doesn't like
441 the CHS values used by the partitions in the protective or
442 hybrid MBR. In particular, the GPT specification requires a CHS
443 value of 0xFFFFFF for over-8GiB partitions, but this value is
444 technically illegal by the usual standards. Some BIOSes hang if
445 they encounter this value. This option will recompute a more
446 normal CHS value -- 0xFEFFFF for over-8GiB partitions, enabling
447 these BIOSes to boot.
448
449
450 i Show detailed partition information. This option is identical to
451 the 'i' option on the main menu.
452
453
454 j Adjust the location of the main partition table. This value is
455 normally 2, but it may need to be increased in some cases, such
456 as when a system-on-chip (SoC) is hard-coded to read boot code
457 from sector 2. I recommend against adjusting this value unless
458 doing so is absolutely necessary.
459
460
461 l Change the sector alignment value. Disks with more logical sec‐
462 tors per physical sectors (such as modern Advanced Format
463 drives), some RAID configurations, and many SSD devices, can
464 suffer performance problems if partitions are not aligned prop‐
465 erly for their internal data structures. On new disks, GPT fdisk
466 attempts to align partitions on 1MiB boundaries (2048-sectors on
467 disks with 512-byte sectors) by default, which optimizes perfor‐
468 mance for all of these disk types. On pre-partitioned disks, GPT
469 fdisk attempts to identify the alignment value used on that
470 disk, but will set 8-sector alignment on disks larger than 300
471 GB even if lesser alignment values are detected. In either case,
472 it can be changed by using this option.
473
474
475 m Return to the main menu. This option enables you to enter
476 main-menu commands.
477
478
479 n Create a new protective MBR. Use this option if the current pro‐
480 tective MBR is damaged in a way that gdisk doesn't automatically
481 detect and correct, or if you want to convert a hybrid MBR into
482 a "pure" GPT with a conventional protective MBR.
483
484
485 o Print protective MBR data. You can see a summary of the protec‐
486 tive MBR's partitions with this option. This may enable you to
487 spot glaring problems or help identify the partitions in a
488 hybrid MBR.
489
490
491 p Print the partition table. This option is identical to the 'p'
492 option in the main menu.
493
494
495 q Quit without saving changes. This option is identical to the 'q'
496 option in the main menu.
497
498
499 r Enter the recovery & transformations menu. This option is iden‐
500 tical to the 'r' option on the main menu.
501
502
503 s Resize partition table. The default partition table size is 128
504 entries. Officially, sizes of less than 16KB (128 entries,
505 given the normal entry size) are unsupported by the GPT specifi‐
506 cation; however, in practice they seem to work, and can some‐
507 times be useful in converting MBR disks. Larger sizes also work
508 fine. OSes may impose their own limits on the number of parti‐
509 tions, though.
510
511
512 t Swap two partitions' entries in the partition table. One parti‐
513 tion may be empty. For instance, if partitions 1-4 are defined,
514 transposing 1 and 5 results in a table with partitions numbered
515 from 2-5. Transposing partitions in this way has no effect on
516 their disk space allocation; it only alters their order in the
517 partition table.
518
519
520 u Replicate the current device's partition table on another
521 device. You will be prompted to type the new device's filename.
522 After the write operation completes, you can continue editing
523 the original device's partition table. Note that the replicated
524 partition table is an exact copy, including all GUIDs; if the
525 device should have its own unique GUIDs, you should use the f
526 option on the new disk.
527
528
529 v Verify disk. This option is identical to the 'v' option in the
530 main menu.
531
532
533 z Zap (destroy) the GPT data structures and exit. Use this option
534 if you want to repartition a GPT disk using fdisk or some other
535 GPT-unaware program. You'll be given the choice of preserving
536 the existing MBR, in case it's a hybrid MBR with salvageable
537 partitions or if you've already created new MBR partitions and
538 want to erase the remnants of your GPT partitions. If you've
539 already created new MBR partitions, it's conceivable that this
540 option will damage the first and/or last MBR partitions! Such an
541 event is unlikely, but could occur if your new MBR partitions
542 overlap the old GPT data structures.
543
544
545 ? Print the menu. This option (or any unrecognized entry) displays
546 a summary of the menu options.
547
548
549 In many cases, you can press the Enter key to select a default option
550 when entering data. When only one option is possible, gdisk usually
551 bypasses the prompt entirely.
552
553
555 Known bugs and limitations include:
556
557
558 * The program compiles correctly only on Linux, FreeBSD, Mac OS X,
559 and Windows. Linux versions for x86-64 (64-bit), x86 (32-bit),
560 and PowerPC (32-bit) have been tested, with the x86-64 version
561 having seen the most testing. Under FreeBSD, 32-bit (x86) and
562 64-bit (x86-64) versions have been tested. Only 32-bit versions
563 for Mac OS X and Windows have been tested by the author,
564 although I've heard of 64-bit versions being successfully com‐
565 piled.
566
567
568 * The FreeBSD version of the program can't write changes to the
569 partition table to a disk when existing partitions on that disk
570 are mounted. (The same problem exists with many other FreeBSD
571 utilities, such as gpt, fdisk, and dd.) This limitation can be
572 overcome by typing sysctl kern.geom.debugflags=16 at a shell
573 prompt.
574
575
576 * The fields used to display the start and end sector numbers for
577 partitions in the 'p' command are 14 characters wide. This
578 translates to a limitation of about 45 PiB. On larger disks, the
579 displayed columns will go out of alignment.
580
581
582 * In the Windows version, only ASCII characters are supported in
583 the partition name field. If an existing partition uses
584 non-ASCII UTF-16 characters, they're likely to be corrupted in
585 the 'i' and 'p' menu options' displays; however, they should be
586 preserved when loading and saving partitions. Binaries for
587 Linux, FreeBSD, and OS X support full UTF-16 partition names.
588
589
590 * The program can load only up to 128 partitions (4 primary parti‐
591 tions and 124 logical partitions) when converting from MBR for‐
592 mat. This limit can be raised by changing the #define
593 MAX_MBR_PARTS line in the basicmbr.h source code file and recom‐
594 piling; however, such a change will require using a
595 larger-than-normal partition table. (The limit of 128 partitions
596 was chosen because that number equals the 128 partitions sup‐
597 ported by the most common partition table size.)
598
599
600 * Converting from MBR format sometimes fails because of insuffi‐
601 cient space at the start or (more commonly) the end of the disk.
602 Resizing the partition table (using the 's' option in the
603 experts' menu) can sometimes overcome this problem; however, in
604 extreme cases it may be necessary to resize a partition using
605 GNU Parted or a similar tool prior to conversion with gdisk.
606
607
608 * MBR conversions work only if the disk has correct LBA partition
609 descriptors. These descriptors should be present on any disk
610 over 8 GiB in size or on smaller disks partitioned with any but
611 very ancient software.
612
613
614 * BSD disklabel support can create first and/or last partitions
615 that overlap with the GPT data structures. This can sometimes be
616 compensated by adjusting the partition table size, but in
617 extreme cases the affected partition(s) may need to be deleted.
618
619
620 * Because of the highly variable nature of BSD disklabel struc‐
621 tures, conversions from this form may be unreliable -- parti‐
622 tions may be dropped, converted in a way that creates overlaps
623 with other partitions, or converted with incorrect start or end
624 values. Use this feature with caution!
625
626
627 * Booting after converting an MBR or BSD disklabel disk is likely
628 to be disrupted. Sometimes re-installing a boot loader will fix
629 the problem, but other times you may need to switch boot load‐
630 ers. Except on EFI-based platforms, Windows through at least
631 Windows 7 doesn't support booting from GPT disks. Creating a
632 hybrid MBR (using the 'h' option on the recovery & transforma‐
633 tion menu) or abandoning GPT in favor of MBR may be your only
634 options in this case.
635
636
638 Primary author: Roderick W. Smith (rodsmith@rodsbooks.com)
639
640 Contributors:
641
642 * Yves Blusseau (1otnwmz02@sneakemail.com)
643
644 * David Hubbard (david.c.hubbard@gmail.com)
645
646 * Justin Maggard (justin.maggard@netgear.com)
647
648 * Dwight Schauer (dschauer@gmail.com)
649
650 * Florian Zumbiehl (florz@florz.de)
651
652
653
655 cfdisk (8), cgdisk (8), fdisk (8), mkfs (8), parted (8), sfdisk (8)
656 sgdisk (8) fixparts (8)
657
658 http://en.wikipedia.org/wiki/GUID_Partition_Table
659
660 http://developer.apple.com/technotes/tn2006/tn2166.html
661
662 http://www.rodsbooks.com/gdisk/
663
664
666 The gdisk command is part of the GPT fdisk package and is available
667 from Rod Smith.
668
669
670
671Roderick W. Smith 1.0.4 GDISK(8)