Guid Partition Table Header - Intel Extensible Firmware Interface Specification

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
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