Table 16-1. GUID Partition Table Header
Mnemonic
Signature
Revision
HeaderSize
HeaderCRC32
Reserved
MyLBA
AlternateLBA
FirstUsableLBA
LastUsableLBA
DiskGUID
PartitionEntryLBA
NumberOfPartitionEntries
SizeOfPartitionEntry
PartitionEntryArrayCRC32
Reserved
The following test must be performed to determine if a GUID Partition Table is valid:
•
Check the GUID Partition Table Signature
•
Check the GUID Partition Table CRC
•
Check that the MyLBA entry points to the LBA that contains the GUID Partition Table
•
Check the CRC of the GUID Partition Entry Array
Version 1.02
Byte
Byte
Offset
Length
Description
0
8
Identifies EFI-compatible partition table header.
This value must contain the string "EFI PART",
0x5452415020494645.
8
4
The specification revision number that this header
complies to. For version 1.0 of the specification
the correct value is 0x00010000.
12
4
Size in bytes of the GUID Partition Table Header.
16
4
CRC32 checksum for the GUID Partition Table
Header structure. The ranged defined by
HeaderSize is "check-summed".
20
4
Must be zero.
24
8
The LBA that contains this data structure.
32
8
LBA address of the alternate GUID Partition Table
Header.
40
8
The first usable logical block that may be
contained in a GUID Partition Entry.
48
8
The last usable logical block that may be
contained in a GUID Partition Entry.
56
16
GUID that can be used to uniquely identify the
disk.
72
8
The starting LBA of the GUID Partition Entry array.
80
4
The number of Partition Entries in the GUID
Partition Entry array.
84
4
The size, in bytes, of each the GUID Partition
Entry structures in the GUID Partition Entry array.
Must be a multiple of 8.
88
4
The CRC32 of the GUID Partition Entry array.
Starts at Partition Entry LBA and is
NumberOfPartitionEntries * SizeOfPartitionEntry in
byte length.
92
BlockSize
The rest of the block is reserved by EFI and must
– 92
be zero.
12/12/00
File System Format
311
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