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 sgdisk). 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.
193
194
195 n Create a new partition. This command is modeled after the equiv‐
196 alent fdisk option, although some differences exist. You enter a
197 partition number, starting sector, and an ending sector. Both
198 start and end sectors can be specified in absolute terms as sec‐
199 tor numbers or as positions measured in kibibytes (K), mebibytes
200 (M), gibibytes (G), tebibytes (T), or pebibytes (P); for
201 instance, 40M specifies a position 40MiB from the start of the
202 disk. You can specify locations relative to the start or end of
203 the specified default range by preceding the number by a '+' or
204 '-' symbol, as in +2G to specify a point 2GiB after the default
205 start sector, or -200M to specify a point 200MiB before the last
206 available sector. Pressing the Enter key with no input specifies
207 the default value, which is the start of the largest available
208 block for the start sector and the end of the same block for the
209 end sector.
210
211
212 o Clear out all partition data. This includes GPT header data, all
213 partition definitions, and the protective MBR. The sector align‐
214 ment is reset to the default (1MB, or 2048 sectors on a disk
215 with 512-byte sectors).
216
217
218 p Display basic partition summary data. This includes partition
219 numbers, starting and ending sector numbers, partition sizes,
220 gdisk's partition types codes, and partition names. For addi‐
221 tional information, use the 'i' command.
222
223
224 q Quit from the program without saving your changes. Use this
225 option if you just wanted to view information or if you make a
226 mistake and want to back out of all your changes.
227
228
229 r Enter the recovery & transformation menu. This menu includes
230 emergency recovery options (to fix damaged GPT data structures)
231 and options to transform to or from other partitioning systems,
232 including creating hybrid MBRs.
233
234
235 s Sort partition entries. GPT partition numbers need not match the
236 order of partitions on the disk. If you want them to match, you
237 can use this option. Note that some partitioning utilities sort
238 partitions whenever they make changes. Such changes will be
239 reflected in your device filenames, so you may need to edit
240 /etc/fstab if you use this option.
241
242
243 t Change a single partition's type code. You enter the type code
244 using a two-byte hexadecimal number, as described earlier. You
245 may also enter a GUID directly, if you have one and gdisk
246 doesn't know it.
247
248
249 v Verify disk. This option checks for a variety of problems, such
250 as incorrect CRCs and mismatched main and backup data. This
251 option does not automatically correct most problems, though; for
252 that, you must use options on the recovery & transformation
253 menu. If no problems are found, this command displays a summary
254 of unallocated disk space.
255
256
257 w Write data. Use this command to save your changes.
258
259
260 x Enter the experts' menu. Using this option provides access to
261 features you can use to get into even more trouble than the main
262 menu allows.
263
264 ? Print the menu. Type this command (or any other unrecognized
265 command) to see a summary of available options.
266
267
268 The second gdisk menu is the recovery & transformation menu, which pro‐
269 vides access to data recovery options and features related to the
270 transformation of partitions between partitioning schemes (converting
271 BSD disklabels into GPT partitions or creating hybrid MBRs, for
272 instance). A few options on this menu duplicate functionality on the
273 main menu, for the sake of convenience. The options on this menu are:
274
275
276 b Rebuild GPT header from backup. You can use the backup GPT
277 header to rebuild the main GPT header with this option. It's
278 likely to be useful if your main GPT header was damaged or
279 destroyed (say, by sloppy use of dd).
280
281
282 c Load backup partition table. Ordinarily, gdisk uses only the
283 main partition table (although the backup's integrity is checked
284 when you launch the program). If the main partition table has
285 been damaged, you can use this option to load the backup from
286 disk and use it instead. Note that this will almost certainly
287 produce no or strange partition entries if you've just converted
288 an MBR disk to GPT format, since there will be no backup parti‐
289 tion table on disk.
290
291
292 d Use main GPT header and rebuild the backup. This option is
293 likely to be useful if the backup GPT header has been damaged or
294 destroyed.
295
296
297 e Load main partition table. This option reloads the main parti‐
298 tion table from disk. It's only likely to be useful if you've
299 tried to use the backup partition table (via 'c') but it's in
300 worse shape then the main partition table.
301
302
303 f Load MBR and build fresh GPT from it. Use this option if your
304 GPT is corrupt or conflicts with the MBR and you want to use the
305 MBR as the basis for a new set of GPT partitions.
306
307
308 g Convert GPT into MBR and exit. This option converts as many par‐
309 titions as possible into MBR form, destroys the GPT data struc‐
310 tures, saves the new MBR, and exits. Use this option if you've
311 tried GPT and find that MBR works better for you. Note that
312 this function generates up to four primary MBR partitions or
313 three primary partitions and as many logical partitions as can
314 be generated. Each logical partition requires at least one unal‐
315 located block immediately before its first block. Therefore, it
316 may be possible to convert a maximum of four partitions on disks
317 with tightly-packed partitions; however, if free space was
318 inserted between partitions when they were created, and if the
319 disk is under 2 TiB in size, it should be possible to convert
320 all the partitions to MBR form. See also the 'h' option.
321
322
323 h Create a hybrid MBR. This is an ugly workaround that enables
324 GPT-unaware OSes, or those that can't boot from a GPT disk, to
325 access up to three of the partitions on the disk by creating MBR
326 entries for them. Note that these hybrid MBR entries can easily
327 go out of sync with the GPT entries, particularly when
328 hybrid-unaware GPT utilities are used to edit the disk. Thus,
329 you may need to re-create the hybrid MBR if you use such tools.
330 Unlike the 'g' option, this option does not support converting
331 any partitions into MBR logical partitions.
332
333
334 i Show detailed partition information. This option is identical to
335 the 'i' option on the main menu.
336
337
338 l Load partition data from a backup file. This option is the
339 reverse of the 'b' option on the main menu. Note that restoring
340 partition data from anything but the original disk is not recom‐
341 mended.
342
343
344 m Return to the main menu. This option enables you to enter
345 main-menu commands.
346
347
348 o Print protective MBR data. You can see a summary of the protec‐
349 tive MBR's partitions with this option. This may enable you to
350 spot glaring problems or help identify the partitions in a
351 hybrid MBR.
352
353
354 p Print the partition table. This option is identical to the 'p'
355 option in the main menu.
356
357
358 q Quit without saving changes. This option is identical to the 'q'
359 option in the main menu.
360
361
362 t Transform BSD partitions into GPT partitions. This option works
363 on BSD disklabels held within GPT (or converted MBR) partitions.
364 Converted partitions' type codes are likely to need manual
365 adjustment. gdisk will attempt to convert BSD disklabels stored
366 on the main disk when launched, but this conversion is likely to
367 produce first and/or last partitions that are unusable. The many
368 BSD variants means that the probability of gdisk being unable to
369 convert a BSD disklabel is high compared to the likelihood of
370 problems with an MBR conversion.
371
372
373 v Verify disk. This option is identical to the 'v' option in the
374 main menu.
375
376
377 w Write table to disk and exit. This option is identical to the
378 'w' option in the main menu.
379
380
381 x Enter the experts' menu. This option is identical to the 'x'
382 option in the main menu.
383
384
385 ? Print the menu. This option (or any unrecognized entry) displays
386 a summary of the menu options.
387
388
389 The third gdisk menu is the experts' menu. This menu provides advanced
390 options that aren't closely related to recovery or transformation
391 between partitioning systems. Its options are:
392
393
394 a Set attributes. GPT provides a 64-bit attributes field that can
395 be used to set features for each partition. gdisk supports four
396 attributes: system partition, read-only, hidden, and do not
397 automount. You can set other attributes, but their numbers
398 aren't translated into anything useful. In practice, most OSes
399 seem to ignore these attributes.
400
401
402 c Change partition GUID. You can enter a custom unique GUID for a
403 partition using this option. (Note this refers to the GUID that
404 uniquely identifies a partition, not to its type code, which you
405 can change with the 't' main-menu option.) Ordinarily, gdisk
406 assigns this number randomly; however, you might want to adjust
407 the number manually if you've wound up with the same GUID on two
408 partitions because of buggy GUID assignments (hopefully not in
409 gdisk) or sheer incredible coincidence.
410
411
412 d Display the sector alignment value. See the description of the
413 'l' option for more details.
414
415
416 e Move backup GPT data structures to the end of the disk. Use this
417 command if you've added disks to a RAID array, thus creating a
418 virtual disk with space that follows the backup GPT data struc‐
419 tures. This command moves the backup GPT data structures to the
420 end of the disk, where they belong.
421
422
423 f Randomize the disk's GUID and all partitions' unique GUIDs (but
424 not their partition type code GUIDs). This function may be used
425 after cloning a disk with another utility in order to render all
426 GUIDs once again unique.
427
428
429 g Change disk GUID. Each disk has a unique GUID code, which gdisk
430 assigns randomly upon creation of the GPT data structures. You
431 can generate a fresh random GUID or enter one manually with this
432 option.
433
434
435 h Recompute CHS values in protective or hybrid MBR. This option
436 can sometimes help if a disk utility, OS, or BIOS doesn't like
437 the CHS values used by the partitions in the protective or
438 hybrid MBR. In particular, the GPT specification requires a CHS
439 value of 0xFFFFFF for over-8GiB partitions, but this value is
440 technically illegal by the usual standards. Some BIOSes hang if
441 they encounter this value. This option will recompute a more
442 normal CHS value -- 0xFEFFFF for over-8GiB partitions, enabling
443 these BIOSes to boot.
444
445
446 i Show detailed partition information. This option is identical to
447 the 'i' option on the main menu.
448
449
450 j Adjust the location of the main partition table. This value is
451 normally 2, but it may need to be increased in some cases, such
452 as when a system-on-chip (SoC) is hard-coded to read boot code
453 from sector 2. I recommend against adjusting this value unless
454 doing so is absolutely necessary.
455
456
457 l Change the sector alignment value. Disks with more logical sec‐
458 tors per physical sectors (such as modern Advanced Format
459 drives), some RAID configurations, and many SSD devices, can
460 suffer performance problems if partitions are not aligned prop‐
461 erly for their internal data structures. On new disks, GPT fdisk
462 attempts to align partitions on 1MiB boundaries (2048-sectors on
463 disks with 512-byte sectors) by default, which optimizes perfor‐
464 mance for all of these disk types. On pre-partitioned disks, GPT
465 fdisk attempts to identify the alignment value used on that
466 disk, but will set 8-sector alignment on disks larger than 300
467 GB even if lesser alignment values are detected. In either case,
468 it can be changed by using this option.
469
470
471 m Return to the main menu. This option enables you to enter
472 main-menu commands.
473
474
475 n Create a new protective MBR. Use this option if the current pro‐
476 tective MBR is damaged in a way that gdisk doesn't automatically
477 detect and correct, or if you want to convert a hybrid MBR into
478 a "pure" GPT with a conventional protective MBR.
479
480
481 o Print protective MBR data. You can see a summary of the protec‐
482 tive MBR's partitions with this option. This may enable you to
483 spot glaring problems or help identify the partitions in a
484 hybrid MBR.
485
486
487 p Print the partition table. This option is identical to the 'p'
488 option in the main menu.
489
490
491 q Quit without saving changes. This option is identical to the 'q'
492 option in the main menu.
493
494
495 r Enter the recovery & transformations menu. This option is iden‐
496 tical to the 'r' option on the main menu.
497
498
499 s Resize partition table. The default partition table size is 128
500 entries. Officially, sizes of less than 16KB (128 entries,
501 given the normal entry size) are unsupported by the GPT specifi‐
502 cation; however, in practice they seem to work, and can some‐
503 times be useful in converting MBR disks. Larger sizes also work
504 fine. OSes may impose their own limits on the number of parti‐
505 tions, though.
506
507
508 t Swap two partitions' entries in the partition table. One parti‐
509 tion may be empty. For instance, if partitions 1-4 are defined,
510 transposing 1 and 5 results in a table with partitions numbered
511 from 2-5. Transposing partitions in this way has no effect on
512 their disk space allocation; it only alters their order in the
513 partition table.
514
515
516 u Replicate the current device's partition table on another
517 device. You will be prompted to type the new device's filename.
518 After the write operation completes, you can continue editing
519 the original device's partition table. Note that the replicated
520 partition table is an exact copy, including all GUIDs; if the
521 device should have its own unique GUIDs, you should use the f
522 option on the new disk.
523
524
525 v Verify disk. This option is identical to the 'v' option in the
526 main menu.
527
528
529 z Zap (destroy) the GPT data structures and exit. Use this option
530 if you want to repartition a GPT disk using fdisk or some other
531 GPT-unaware program. You'll be given the choice of preserving
532 the existing MBR, in case it's a hybrid MBR with salvageable
533 partitions or if you've already created new MBR partitions and
534 want to erase the remnants of your GPT partitions. If you've
535 already created new MBR partitions, it's conceivable that this
536 option will damage the first and/or last MBR partitions! Such an
537 event is unlikely, but could occur if your new MBR partitions
538 overlap the old GPT data structures.
539
540
541 ? Print the menu. This option (or any unrecognized entry) displays
542 a summary of the menu options.
543
544
545 In many cases, you can press the Enter key to select a default option
546 when entering data. When only one option is possible, gdisk usually
547 bypasses the prompt entirely.
548
549
551 Known bugs and limitations include:
552
553
554 * The program compiles correctly only on Linux, FreeBSD, Mac OS X,
555 and Windows. Linux versions for x86-64 (64-bit), x86 (32-bit),
556 and PowerPC (32-bit) have been tested, with the x86-64 version
557 having seen the most testing. Under FreeBSD, 32-bit (x86) and
558 64-bit (x86-64) versions have been tested. Only 32-bit versions
559 for Mac OS X and Windows have been tested by the author,
560 although I've heard of 64-bit versions being successfully com‐
561 piled.
562
563
564 * The FreeBSD version of the program can't write changes to the
565 partition table to a disk when existing partitions on that disk
566 are mounted. (The same problem exists with many other FreeBSD
567 utilities, such as gpt, fdisk, and dd.) This limitation can be
568 overcome by typing sysctl kern.geom.debugflags=16 at a shell
569 prompt.
570
571
572 * The fields used to display the start and end sector numbers for
573 partitions in the 'p' command are 14 characters wide. This
574 translates to a limitation of about 45 PiB. On larger disks, the
575 displayed columns will go out of alignment.
576
577
578 * In the Windows version, only ASCII characters are supported in
579 the partition name field. If an existing partition uses
580 non-ASCII UTF-16 characters, they're likely to be corrupted in
581 the 'i' and 'p' menu options' displays; however, they should be
582 preserved when loading and saving partitions. Binaries for
583 Linux, FreeBSD, and OS X support full UTF-16 partition names.
584
585
586 * The program can load only up to 128 partitions (4 primary parti‐
587 tions and 124 logical partitions) when converting from MBR for‐
588 mat. This limit can be raised by changing the #define
589 MAX_MBR_PARTS line in the basicmbr.h source code file and recom‐
590 piling; however, such a change will require using a
591 larger-than-normal partition table. (The limit of 128 partitions
592 was chosen because that number equals the 128 partitions sup‐
593 ported by the most common partition table size.)
594
595
596 * Converting from MBR format sometimes fails because of insuffi‐
597 cient space at the start or (more commonly) the end of the disk.
598 Resizing the partition table (using the 's' option in the
599 experts' menu) can sometimes overcome this problem; however, in
600 extreme cases it may be necessary to resize a partition using
601 GNU Parted or a similar tool prior to conversion with gdisk.
602
603
604 * MBR conversions work only if the disk has correct LBA partition
605 descriptors. These descriptors should be present on any disk
606 over 8 GiB in size or on smaller disks partitioned with any but
607 very ancient software.
608
609
610 * BSD disklabel support can create first and/or last partitions
611 that overlap with the GPT data structures. This can sometimes be
612 compensated by adjusting the partition table size, but in
613 extreme cases the affected partition(s) may need to be deleted.
614
615
616 * Because of the highly variable nature of BSD disklabel struc‐
617 tures, conversions from this form may be unreliable -- parti‐
618 tions may be dropped, converted in a way that creates overlaps
619 with other partitions, or converted with incorrect start or end
620 values. Use this feature with caution!
621
622
623 * Booting after converting an MBR or BSD disklabel disk is likely
624 to be disrupted. Sometimes re-installing a boot loader will fix
625 the problem, but other times you may need to switch boot load‐
626 ers. Except on EFI-based platforms, Windows through at least
627 Windows 7 doesn't support booting from GPT disks. Creating a
628 hybrid MBR (using the 'h' option on the recovery & transforma‐
629 tion menu) or abandoning GPT in favor of MBR may be your only
630 options in this case.
631
632
634 Primary author: Roderick W. Smith (rodsmith@rodsbooks.com)
635
636 Contributors:
637
638 * Yves Blusseau (1otnwmz02@sneakemail.com)
639
640 * David Hubbard (david.c.hubbard@gmail.com)
641
642 * Justin Maggard (justin.maggard@netgear.com)
643
644 * Dwight Schauer (dschauer@gmail.com)
645
646 * Florian Zumbiehl (florz@florz.de)
647
648
649
651 cfdisk (8), cgdisk (8), fdisk (8), mkfs (8), parted (8), sfdisk (8)
652 sgdisk (8) fixparts (8)
653
654 http://en.wikipedia.org/wiki/GUID_Partition_Table
655
656 http://developer.apple.com/technotes/tn2006/tn2166.html
657
658 http://www.rodsbooks.com/gdisk/
659
660
662 The gdisk command is part of the GPT fdisk package and is available
663 from Rod Smith.
664
665
666
667Roderick W. Smith 1.0.3 GDISK(8)