GPT: Difference between revisions

[unchecked revision]

← Older edit

Content deleted Content added

VisualWikitext

Revision as of 15:45, 5 October 2022 view source Ori (talk \| contribs) 8 edits m Fix typo ← Older edit		Latest revision as of 04:40, 9 July 2023 view source osdev>Khaledhammouda No edit summary
(2 intermediate revisions by 2 users not shown)
Line 77: \|0x5C\|\|'''blocksize'''-0x5C\|\|Reserved (should be zeroed) \|} The Partition Entry array can contain unused entries -- that is, the GUID value is set to zero. For the purposes of the GPT header, these should be counted when considering the Number of Partition Entries field, and should also be taken into account when calculating the CRC32 of the entire array. There should be no more entries in the array, unused or otherwise, than are indicated by this field. Note: it is somewhat vague what the Number of Partition Entries field contain. For many applications that is the number of '''actually used''' entries, while many partitioning tools (most notably fdisk and gdisk) handles that as the number of '''maximum available''' entries, using full zero Partition Type to mark empty entries. Unfortunately both interpretation is suggested by the EFI spec, so this is unclear. One thing is certain, there should be no more entries (empty or not) than this field. For the checksums in the header, the CCITT32 ANSI CRC method is used, the one with the polynomial 0x04c11db7 (same as in gzip, and different to the Castagnoli CRC32 that hardware accelerated CRC instructions calculate). The header checksum field at 0x10 is zeroed during calculation and the reserved data are not included. Line 111: The following utilities can handle GPT: * [http://www.gnu.org/software/parted/manual/parted.html parted], [http://linux.die.net/man/8/gparted gparted], [http://www.rodsbooks.com/gdisk/ gdisk] on Linux * [~~http~~https://~~developer~~www.~~apple~~unix.com/~~library~~man-page/~~mac~~OSX/~~#documentation~~8/~~Darwin~~diskutil/~~Reference/ManPages/man8/diskutil.8~~ diskutil] on MacOSX * [http://technet.microsoft.com/en-us/library/bb490893.aspx diskpart] on Windows (Vista and upwards) * [http://www.freebsd.org/cgi/man.cgi?query=gpt&manpath=FreeBSD+7.1-RELEASE gpt] on MacOSX and BSDs. Line 135: * [[wikipedia:BIOS_Boot_partition\|Wikipedia: BIOS Boot partition]] [[Category:Disks]] [[Category:UEFI]] [[Category:Firmware]]