File allocation table, Hardware, Device path – Intel Extensible Firmware Interface User Manual

Page 1054: Guid partitions, File allocation, Table

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Extensible Firmware Interface Specification

Glossary-6

12/01/02

Version 1.10

FAT

See

File Allocation Table

.

File Allocation Table (FAT)

A table that is used to identify the clusters that make up a disk file. File
allocation tables come in three flavors: FAT12, which uses 12 bits for cluster
numbers; FAT16, which uses 16 bits; and FAT32, which allots 32 bits but only
uses 28 (the other 4 bits are reserved for future use).

File Handle Protocol

A component of the

File System Protocol

. It provides access to a file or

directory. Also called the EFI File Handle Protocol.

File System Protocol

A protocol that is used during boot services to obtain file-based access to a
device. It has two parts, a

Simple File System Protocol

that provides a minimal

interface for file-type access to a device, and a

File Handle Protocol

that

provides access to a file or directory.

Firmware

Any software that is included in read-only memory (ROM).

Globally Unique Identifier (GUID)

A 128-bit value used to differentiate services and structures in the boot services
environment. The format of a GUID is defined in Appendix A. See

Protocol

.

GUID Partition Entry

A data structure that characterizes a

GUID Partition

. Among other things, it

specifies the starting and ending LBA of the partition.

GUID Partition Table Header

The header in a

GUID Partition Table

. Among other things, it contains the

number of partition entries in the table and the first and last blocks that can be
used for the entries.

GUID Partition Table

A data structure that describes a

GUID Partition

. It consists of an

GUID

Partition Table Header

and, typically, at least one

GUID Partition Entry

.

There are two partition tables on an

EFI Hard Disk

: the Primary Partition Table

(located in block 1 of the disk) and a Backup Partition Table (located in the last
block of the disk). The Backup Table is a copy of the Primary Table.

GUID Partition

A contiguous group of sectors on an

EFI Hard Disk

.

Handle

See

Device Handle

.

Hardware Device Path

A Device Path that defines how a hardware device is attached to the resource
domain of a system (the resource domain is simply the shared memory, memory
mapped I/O, and I/O space of the system).

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