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GUID Partition Table

GUID Partition Table

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In computer hardware
Computer hardware
Personal computer hardware are component devices which are typically installed into or peripheral to a computer case to create a personal computer upon which system software is installed including a firmware interface such as a BIOS and an operating system which supports application software that...

, GUID
Globally Unique Identifier
A globally unique identifier is a unique reference number used as an identifier in computer software. The term GUID also is used for Microsoft's implementation of the Universally unique identifier standard....

 Partition Table
(GPT) is a standard for the layout of the partition table
Partition table
The term partition table is most commonly associated with partition table but it may be used generically to refer to other "formats" that divide a disk drive into partitions, such as: GUID Partition Table, Apple partition map, or BSD disklabel.An alternative term to generically refer to partition...

 on a physical hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

. Although it forms a part of the Extensible Firmware Interface
Extensible Firmware Interface
The Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware...

 (EFI) standard (Intel's proposed replacement for the PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...

 BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....

), it is also used on some BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....

 systems because of the limitations of MBR
Master boot record
A master boot record is a type of boot sector popularized by the IBM Personal Computer. It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk...

 partition tables, which restrict a disk partition's size to a maximum of 2.19 TB
Terabyte
The terabyte is a multiple of the unit byte for digital information. The prefix tera means 1012 in the International System of Units , and therefore 1 terabyte is , or 1 trillion bytes, or 1000 gigabytes. 1 terabyte in binary prefixes is 0.9095 tebibytes, or 931.32 gibibytes...

 (2.19 × 1012 byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...

s) or 2 TiB
TIB
TIB may mean:* Therapy Interfering Behavior* Forbundet Træ-Industri-Byg i Danmark, the Danish Timber Industry and Construction Workers' Union* Tibet* The Win32 Thread Information Block, an element in Microsoft Windows computer programming....

−512 bytes (2,199,023,255,040 bytes or 4,294,967,295 (232−1) sectors × 512 (29) bytes per sector). GPT allows for a maximum disk and partition size of 9.4 ZB
Zettabyte
A zettabyte is a unit of information or computer storage equal to one sextillion bytes....

 (9.4 × 1021 bytes) or 8 ZiB
Zib
Zib can be:* an alternate transliteration of Ziv;* an alternate transliteration for al-Zeeb, a Palestinian village depopulated in the lead up to and during the 1948 Arab-Israeli war....

−512 bytes (9,444,732,965,739,290,426,880 bytes or 18,446,744,073,709,551,615 (264−1) sectors × 512 (29) bytes per sector).

, most current operating systems support GPT, although some (including Mac OS X and Windows) only support booting to GPT partitions on systems with EFI firmware.


History


The widespread MBR
Master boot record
A master boot record is a type of boot sector popularized by the IBM Personal Computer. It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk...

 partitioning scheme, dating from the early 1980s, imposed limitations which affected the use of modern hardware. Intel therefore developed a new partition-table format in the late 1990s as part of what eventually became UEFI. The GPT forms a subset of the UEFI specification.

Features


MBR-based partition table schemes insert the partitioning information in the master boot record
Master boot record
A master boot record is a type of boot sector popularized by the IBM Personal Computer. It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk...

 (MBR) (which on a BIOS system is also the container for code that begins the process of booting the system). In a GPT, partition table information is stored in the GPT header, but to maintain compatibility, GPT retains the MBR entry as the first sector on the disk followed by a primary partition table header, the actual beginning of a GPT.

Like modern MBRs, GPTs use logical block addressing
Logical block addressing
Logical block addressing is a common scheme used for specifying the location of blocks of data stored on computer storage devices, generally secondary storage systems such as hard disks....

 (LBA) in place of the historical cylinder-head-sector
Cylinder-head-sector
Cylinder-head-sector, also known as CHS, was an early method for giving addresses to each physical block of data on a hard disk drive. In the case of floppy drives, for which the same exact diskette medium can be truly low-level formatted to different capacities, this is still true.Though CHS...

 (CHS) addressing. Legacy MBR information is contained in LBA 0, the GPT header is in LBA 1, and the partition table itself follows. 64-bit Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s reserve 16,384 bytes (or 32 sector
Disk sector
In computer disk storage, a sector is a subdivision of a track on a magnetic disk or optical disc. Each sector stores a fixed amount of user data. Traditional formatting of these storage media provides space for 512 bytes or 2048 bytes of user-accessible data per sector...

s) for the GPT, leaving LBA 34 as the first usable sector on the disk.

Apple warns: "Do not assume that the block size is always going to be 512 bytes." Modern storage devices such as solid-state drive
Solid-state drive
A solid-state drive , sometimes called a solid-state disk or electronic disk, is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive...

s may contain 1024-byte LBAs and some magneto-optical (MO) drives use 2048-byte sectors (but MO drives are typically not partitioned).

Hard disk manufacturers are transitioning to 4096-byte sectors
Advanced Format
Advanced Format is a generic term pertaining to any sector format used to store data on the magnetic disks in hard disk drives that exceeds 512 to 520 bytes per sector. Advanced Format is also considered a milestone technology in the history of hard-drive storage, where data has been processed in...

. As of 2010, the first such drives continue to present 512-byte physical sectors to the OS, so degraded performance can result when the drive's (hidden) internal 4KiB sector boundaries do not coincide with the 4KiB logical blocks, clusters and virtual memory pages common in many operating systems and file systems. This is a particular problem on writes when the drive is forced to perform two read-modify-write operations to satisfy a single misaligned 4KiB write operation. Such a misalignment occurs by default if the first partition is placed immediately after the GUID partition table, as the next block is LBA 34. The next 4KiB boundary begins with LBA 40.

Drives which boot Intel-based Macs are typically formatted with a GUID Partition Table, rather than with the Apple Partition Map
Apple Partition Map
Apple Partition Map is a partition scheme used to define the low-level organization of data on disks formatted for use with 68K and PowerPC Macintosh computers that was introduced with the Macintosh SE ....

 (APM).

GPT also provides redundancy, writing the GPT header and partition table both at the beginning and at the end of the disk.

Microsoft Windows implementations limit the number of possible partitions to 128.

Legacy MBR (LBA 0)


In the GPT specification, the location corresponding to the MBR in MBR-based disks is structured in a way that prevents MBR-based disk utilities from mis-recognizing, and possibly over-writing, GPT disks. This is referred to as a "protective MBR". In operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s that support GPT-based boot, it is also used to store the first stage of the bootloader code. A single partition type of 0xEE, encompassing the entire GPT drive, is indicated and identifies it as GPT. Operating systems which cannot read GPT disks will generally recognize the disk as containing one partition of unknown type and no empty space, and will typically refuse to modify the disk unless the user explicitly requests and confirms the deletion of this partition. This minimizes accidental erasures. Furthermore, GPT-aware OSes will check the protective MBR and if the enclosed partition type is not of type 0xEE or if there are multiple partitions defined on the target device, the device should not be manipulated .

If the disk exceeds 2 TiB—-the maximum partition size representable using the 32-bit LBAs of the legacy MBR (assuming a 512 byte block size)—-the size of this partition is marked as 2 TiB, ignoring the rest of disk.

Apple's Boot Camp Intel based Apple macs software creates a hybrid partition table to allow the booting of Windows (which at the time of Boot Camp's creation did not support GPT or EFI). In this system the protective partition is reduced in size to cover from sector 1 to the sector before the first regular partition included in the hybrid MBR. Additional MBR partitions are then defined to correspond to the next three GPT partitions.

Partition table header (LBA 1)


The partition table header defines the usable blocks on the disk. It also defines the number and size of the partition entries that make up the partition table. On 64-bit Windows Server 2003 machines, 128 partitions can be created. There are 128 partition entries reserved, each 128 bytes long. (The EFI specification requires that a minimum of 16,384 bytes be reserved for the partition table, so this gives space for 128 partition entries.)

The header contains the disk GUID (Globally Unique Identifier). It records its own size and location (always LBA 1) and the size and location of the secondary GPT header and table (always the last sectors on the disk). Importantly, it also contains a CRC32 checksum for itself and for the partition table, which may be verified by the firmware, bootloader and/or operating system on boot. Because of this, hex editors should not be used to modify the contents of the GPT. Such modification would render the checksum invalid. In this case, the primary GPT may be overwritten with the secondary one by disk recovery software. If both GPTs contain invalid checksums, the disk would be unusable.
Partition table format
Offset Length Contents
0 8 bytes Signature ("EFI PART", 45 46 49 20 50 41 52 54)
8 4 bytes Revision (For GPT version 1.0 (through at least UEFI version 2.3.1), the value is 00 00 01 00)
12 4 bytes Header size in little endian (in bytes, usually 5C 00 00 00 meaning 92 bytes)
16 4 bytes CRC32 of header (0 to header size), with this field zeroed during calculation
20 4 bytes Reserved; must be zero
24 8 bytes Current LBA (location of this header copy)
32 8 bytes Backup LBA (location of the other header copy)
40 8 bytes First usable LBA for partitions (primary partition table last LBA + 1)
48 8 bytes Last usable LBA (secondary partition table first LBA - 1)
56 16 bytes Disk GUID (also referred as UUID on UNIXes)
72 8 bytes Partition entries starting LBA (always 2 in primary copy)
80 4 bytes Number of partition entries
84 4 bytes Size of a partition entry (usually 128)
88 4 bytes CRC32 of partition array
92 * Reserved; must be zeroes for the rest of the block (420 bytes for a 512-byte LBA)
LBA size | Total


The values for current and backup LBAs of the primary header should be the second sector of the disk (1) and the last sector of the disk, respectively. The secondary header at the end of the disk identifies its own table of partition entries, which is located directly before that header.

Partition entries (LBA 2–33)


The GPT uses simple and straightforward entries to describe partitions. The first 16 bytes designate the partition type GUID. For example, the GUID for an EFI System partition
EFI System Partition
The EFI System partition is a partition on a data storage device that is used by machines that adhere to the Extensible Firmware Interface. It contains the boot loader programs for all operating systems installed on the device, device driver files for other devices, and system utility programs...

 is {C12A7328-F81F-11D2-BA4B-00A0C93EC93B}. The second 16 bytes contain a GUID unique to the partition. Starting and ending 64-bit LBAs are also recorded here, and space is allocated for partition names and attributes. As is the nature and purpose of GUIDs, no central registry is needed to ensure the uniqueness of the GUID partition type designators.
GUID partition entry format
Offset Length Contents
0 16 bytes Partition type GUID
16 16 bytes Unique partition GUID
32 8 bytes First LBA (little-endian)
40 8 bytes Last LBA (inclusive, usually odd)
48 8 bytes Attribute flags (e.g. bit 60 denotes read-only)
56 72 bytes Partition name (36 UTF-16LE code units)
128 | Total

Apple warns: "Do not hardwire the current size of the partition entry (128 bytes)." Microsoft TechNet says that attributes are divided into two halves: the lower 4 bytes representing partition independent attributes, and the upper 4 bytes are partition type dependent. Microsoft uses the following bits in general:
Partition attributes
Bit Content
0 System partition (disk partitioning utilities must reserve the partition as is)
2 Legacy BIOS Bootable (equivalent to MBR 80h Active flag)
60 Read-only
62 Hidden
63 Do not automount (i.e., do not assign drive letter)

OS support of GPT


Hybrid MBRs are non-standard and can be interpreted in different ways by different OSes. Unless otherwise noted, OSes provide precedence to the GPT data when a hybrid MBR configuration is encountered.

The term No native support on this arch and version. should be understood this way:
Not supported as data disk, only known legacy partitions found in protective MBR are accessible via the OS. Detachable disks: only support for MBR partitioning; No access with end user applications. GPT contained raw data is accessible with third-party administrator tools for low level disk access. True file system level support in read or read-write form might be subject of software from a third-party vendor.

Unix-class operating systems

OS Version/
edition
Platform Boot from GPT on PC/BIOS Boot from GPT on EFI Note
FreeBSD
FreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...

Since 7.0 x86, x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

In a hybrid configuration, both GPT and MBR partition identifiers may be used.
Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

Most of the x86 Linux distributions

Fedora
Fedora (operating system)
Fedora is a RPM-based, general purpose collection of software, including an operating system based on the Linux kernel, developed by the community-supported Fedora Project and sponsored by Red Hat...

 8+ and Ubuntu
Ubuntu (operating system)
Ubuntu is a computer operating system based on the Debian Linux distribution and distributed as free and open source software. It is named after the Southern African philosophy of Ubuntu...

 8.04+
x86, x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

Some distribution tools, such as fdisk, don't work with GPT.
New tools such as gdisk, GNU Parted
GNU Parted
GNU Parted is a free partition editor, used for creating, destroying, resizing, checking, and copying partitions, and the file systems on them. This is useful for creating space for new operating systems, reorganising hard disk usage, copying data between hard disks, and disk imaging...

, Syslinux
SYSLINUX
The SYSLINUX Project is a suite of lightweight IBM PC MBR bootloaders for starting up computers with the Linux kernel. It is the work of H. Peter Anvin, and consists of several separate systems, the best-known of which is ISOLINUX.-List:...

, grub .96+ patches
GNU GRUB
GNU GRUB is a boot loader package from the GNU Project. GRUB is the reference implementation of the Multiboot Specification, which provides a user the choice to boot one of multiple operating systems installed on a computer or select a specific kernel configuration available on a particular...

 and grub2 have been GPT-enabled.
Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

Since 10.4.0 (some features since 10.4.6) x86, x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

Solaris Since Solaris 10 x86, x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

, SPARC
SPARC
SPARC is a RISC instruction set architecture developed by Sun Microsystems and introduced in mid-1987....


Windows 32-bit versions


Microsoft does not support EFI on 32-bit platforms, and by extension, does not allow booting from GPT partitions.
OS Version/
edition
Platform Boot from GPT on PC/BIOS Boot from GPT on EFI Note
Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...

(2001-10-25) x86 No native support on this architecture and version.
Windows Server 2003
Windows Server 2003
Windows Server 2003 is a server operating system produced by Microsoft, introduced on 24 April 2003. An updated version, Windows Server 2003 R2, was released to manufacturing on 6 December 2005...

(2003-04-24) x86 No native support on this architecture and version.
Windows Server 2003
Windows Server 2003
Windows Server 2003 is a server operating system produced by Microsoft, introduced on 24 April 2003. An updated version, Windows Server 2003 R2, was released to manufacturing on 6 December 2005...

(2005-03-30) x86 Data Disk only MBR takes precedence in hybrid configuration.
Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...

(2005-07-22) x86 MBR takes precedence in hybrid configuration.
Windows Server 2008 (2008-02-27) x86 MBR takes precedence in hybrid configuration.
Windows 7 (2009-10-22) x86 MBR takes precedence in hybrid configuration.

Windows x64 64-bit versions


The following table lists only the 64-bit IA-32
IA-32
IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...

, also called x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

, EM64T, or x64, Windows versions that support GPT. These are also since 2001 the "64-bit" editions for the IA-64 processor platform that come with EFI
Extensible Firmware Interface
The Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware...

 and support GPT boot since the first release, as GPT is the default partitioning type on that platform. The "x64" editions for the x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

 processor platform initially only had limited GPT support until mainstream Windows variants reached parity with the IA-64 variants on the release of Windows Server 2008. Please note that below the so-called "Windows XP" version listed is in fact technically equivalent with the above-mentioned Windows Server 2003 version.
OS Version/
edition
Platform Boot from GPT on PC/BIOS Boot from GPT on EFI Note
Windows Server 2003
Windows Server 2003
Windows Server 2003 is a server operating system produced by Microsoft, introduced on 24 April 2003. An updated version, Windows Server 2003 R2, was released to manufacturing on 6 December 2005...

(2005-04-25) x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

Data disk only MBR takes precedence in hybrid MBR configuration.
Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...

(2005-04-25)
x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

Data disk only MBR takes precedence in hybrid configuration.
Detachable disks: only support for MBR partitioning.
Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...

(2006-07-22) x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

MBR takes precedence in hybrid configuration.
Windows Server 2008
Windows Vista SP1
(2008-02-27) x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

MBR takes precedence in hybrid configuration.
Windows 7 (2009-10-22) x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

MBR takes precedence in hybrid configuration.
Windows Server 2008 R2
Windows Server 2008 R2
Windows Server 2008 R2 is a server operating system produced by Microsoft. It was released to manufacturing on July 22, 2009 and launched on October 22, 2009. According to the Windows Server Team blog, the retail availability was September 14, 2009. It is built on Windows NT 6.1, the same core...

(2009-10-22)
x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

MBR takes precedence in hybrid configuration.

Partition type GUIDs

Assoc. OS Partition type Globally unique identifier (GUID)
(None) Unused entry 00000000-0000-0000-0000-000000000000
MBR partition scheme 024DEE41-33E7-11D3-9D69-0008C781F39F
EFI System partition
EFI System Partition
The EFI System partition is a partition on a data storage device that is used by machines that adhere to the Extensible Firmware Interface. It contains the boot loader programs for all operating systems installed on the device, device driver files for other devices, and system utility programs...

C12A7328-F81F-11D2-BA4B-00A0C93EC93B
BIOS Boot partition 21686148-6449-6E6F-744E-656564454649
Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

Microsoft Reserved Partition
Microsoft Reserved Partition
The Microsoft Reserved Partition, or MSR, is a partition on a data storage device that is labelled with Globally Unique Identifier equal to E3C9E316-0B5C-4DB8-817D-F92DF00215AE. The containing storage device has to use the new GUID Partition Table format, not the traditional master boot record ...

E3C9E316-0B5C-4DB8-817D-F92DF00215AE
Basic data partition
Basic Data Partition
In Microsoft operating systems, when using basic disk partitioned with GUID Partition Table layout, a basic data partition is any partition identified with Globally Unique Identifier of EBD0A0A2-B9E5-4433-87C0-68B6B72699C7....

EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
Logical Disk Manager
Logical Disk Manager
The Logical Disk Manager is an implementation of a logical volume manager for Microsoft Windows NT, developed by Microsoft and Veritas Software. It was introduced with the Windows 2000 operating system, and is supported in Windows XP, Windows Server 2003, Windows Vista and Windows 7...

 metadata partition
5808C8AA-7E8F-42E0-85D2-E1E90434CFB3
Logical Disk Manager
Logical Disk Manager
The Logical Disk Manager is an implementation of a logical volume manager for Microsoft Windows NT, developed by Microsoft and Veritas Software. It was introduced with the Windows 2000 operating system, and is supported in Windows XP, Windows Server 2003, Windows Vista and Windows 7...

 data partition
AF9B60A0-1431-4F62-BC68-3311714A69AD
Windows Recovery Environment DE94BBA4-06D1-4D40-A16A-BFD50179D6AC
IBM General Parallel File System (GPFS) partition 37AFFC90-EF7D-4E96-91C3-2D7AE055B174
HP-UX
HP-UX
HP-UX is Hewlett-Packard's proprietary implementation of the Unix operating system, based on UNIX System V and first released in 1984...

Data partition 75894C1E-3AEB-11D3-B7C1-7B03A0000000
Service Partition E2A1E728-32E3-11D6-A682-7B03A0000000
Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

Linux filesystem data 0FC63DAF-8483-4772-8E79-3D69D8477DE4
RAID partition A19D880F-05FC-4D3B-A006-743F0F84911E
Swap partition 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F
Logical Volume Manager
Logical Volume Manager (Linux)
LVM is a logical volume manager for the Linux kernel; it manages disk drives and similar mass-storage devices, in particular large ones. The term "volume" refers to a disk drive or partition thereof...

 (LVM) partition
E6D6D379-F507-44C2-A23C-238F2A3DF928
Reserved 8DA63339-0007-60C0-C436-083AC8230908
FreeBSD
FreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...

Boot partition 83BD6B9D-7F41-11DC-BE0B-001560B84F0F
Data partition 516E7CB4-6ECF-11D6-8FF8-00022D09712B
Swap partition 516E7CB5-6ECF-11D6-8FF8-00022D09712B
Unix File System
Unix File System
The Unix file system is a file system used by many Unix and Unix-like operating systems. It is also called the Berkeley Fast File System, the BSD Fast File System or FFS...

 (UFS) partition
516E7CB6-6ECF-11D6-8FF8-00022D09712B
Vinum volume manager
Vinum volume manager
Vinum, is a logical volume manager, also called Software RAID, allowing implementations of the RAID-0, RAID-1 and RAID-5 models, both individually and in combination. Vinum is part of the base distribution of the FreeBSD operating system. Versions exist for NetBSD, OpenBSD and DragonFly BSD. Vinum...

 partition
516E7CB8-6ECF-11D6-8FF8-00022D09712B
ZFS
ZFS
In computing, ZFS is a combined file system and logical volume manager designed by Sun Microsystems. The features of ZFS include data integrity verification against data corruption modes , support for high storage capacities, integration of the concepts of filesystem and volume management,...

 partition
516E7CBA-6ECF-11D6-8FF8-00022D09712B
Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

Hierarchical File System Plus (HFS+) partition 48465300-0000-11AA-AA11-00306543ECAC
Apple UFS
Unix File System
The Unix file system is a file system used by many Unix and Unix-like operating systems. It is also called the Berkeley Fast File System, the BSD Fast File System or FFS...

55465300-0000-11AA-AA11-00306543ECAC
ZFS
ZFS
In computing, ZFS is a combined file system and logical volume manager designed by Sun Microsystems. The features of ZFS include data integrity verification against data corruption modes , support for high storage capacities, integration of the concepts of filesystem and volume management,...

6A898CC3-1DD2-11B2-99A6-080020736631
Apple RAID partition 52414944-0000-11AA-AA11-00306543ECAC
Apple RAID partition, offline 52414944-5F4F-11AA-AA11-00306543ECAC
Apple Boot partition 426F6F74-0000-11AA-AA11-00306543ECAC
Apple Label 4C616265-6C00-11AA-AA11-00306543ECAC
Apple TV Recovery partition 5265636F-7665-11AA-AA11-00306543ECAC
Apple Core Storage (i.e. Lion FileVault) partition 53746F72-6167-11AA-AA11-00306543ECAC
Solaris
Solaris Operating System
Solaris is a Unix operating system originally developed by Sun Microsystems. It superseded their earlier SunOS in 1993. Oracle Solaris, as it is now known, has been owned by Oracle Corporation since Oracle's acquisition of Sun in January 2010....

Boot partition 6A82CB45-1DD2-11B2-99A6-080020736631
Root partition 6A85CF4D-1DD2-11B2-99A6-080020736631
Swap partition 6A87C46F-1DD2-11B2-99A6-080020736631
Backup partition 6A8B642B-1DD2-11B2-99A6-080020736631
/usr partition 6A898CC3-1DD2-11B2-99A6-080020736631
/var partition 6A8EF2E9-1DD2-11B2-99A6-080020736631
/home partition 6A90BA39-1DD2-11B2-99A6-080020736631
Alternate sector 6A9283A5-1DD2-11B2-99A6-080020736631
Reserved partition 6A945A3B-1DD2-11B2-99A6-080020736631
6A9630D1-1DD2-11B2-99A6-080020736631
6A980767-1DD2-11B2-99A6-080020736631
6A96237F-1DD2-11B2-99A6-080020736631
6A8D2AC7-1DD2-11B2-99A6-080020736631
NetBSD
NetBSD
NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...

Swap partition 49F48D32-B10E-11DC-B99B-0019D1879648
FFS
Unix File System
The Unix file system is a file system used by many Unix and Unix-like operating systems. It is also called the Berkeley Fast File System, the BSD Fast File System or FFS...

 partition
49F48D5A-B10E-11DC-B99B-0019D1879648
LFS partition 49F48D82-B10E-11DC-B99B-0019D1879648
RAID partition 49F48DAA-B10E-11DC-B99B-0019D1879648
Concatenated partition 2DB519C4-B10F-11DC-B99B-0019D1879648
Encrypted partition 2DB519EC-B10F-11DC-B99B-0019D1879648
ChromeOS ChromeOS kernel FE3A2A5D-4F32-41A7-B725-ACCC3285A309
ChromeOS rootfs 3CB8E202-3B7E-47DD-8A3C-7FF2A13CFCEC
ChromeOS future use 2E0A753D-9E48-43B0-8337-B15192CB1B5E

  1. The GUIDs in this table are written assuming a little-endian byte order. For example, the GUID for an EFI System partition is written as C12A7328-F81F-11D2-BA4B-00A0C93EC93B here, which corresponds to the 16 byte sequence 28 73 2A C1 1F F8 D2 11 BA 4B 00 A0 C9 3E C9 3B — only the first three blocks are byte-swapped.
  2. The formation of this GUID does not follow the GUID definition, it is formed by using the "Hah!IdontneedEFI" ASCII codes. Such formation of "GUID" value breaks down the guaranteed uniqueness of GUID.
  3. Previously Linux used the same GUID for the data partitions as Windows. Linux never had a separate unique partition type GUID defined for its data partitions. This created problems when dual-booting Linux and Windows in UEFI-GPT setup. This new GUID was defined jointly by GPT fdisk and GNU Parted developers. It is identified as type code 8300 in GPT fdisk.
  4. The GUID for /usr on Solaris is used as a generic GUID for ZFS by Mac OS X.
  5. Definitions are in src/sys/sys/disklabel_gpt.h. NetBSD had used the FreeBSD GUIDs before unique NetBSD-specific GUIDs were created.
  6. Definitions are in http://www.chromium.org/chromium-os/chromiumos-design-docs/disk-format.

See also

  • Master boot record
    Master boot record
    A master boot record is a type of boot sector popularized by the IBM Personal Computer. It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk...

  • Globally Unique Identifier
    Globally Unique Identifier
    A globally unique identifier is a unique reference number used as an identifier in computer software. The term GUID also is used for Microsoft's implementation of the Universally unique identifier standard....

     (GUID)
  • Extensible Firmware Interface
    Extensible Firmware Interface
    The Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware...

     (EFI)
  • Disk partitioning
    Disk partitioning
    Disk partitioning is the act of dividing a hard disk drive into multiple logical storage units referred to as partitions, to treat one physical disk drive as if it were multiple disks. Partitions are also termed "slices" for operating systems based on BSD, Solaris or GNU Hurd...


External links