GUID Partition Table
Encyclopedia
In computer hardware
, GUID
Partition Table (GPT) is a standard for the layout of the partition table
on a physical hard disk
. Although it forms a part of the Extensible Firmware Interface
(EFI) standard (Intel's proposed replacement for the PC
BIOS
), it is also used on some BIOS
systems because of the limitations of MBR
partition tables, which restrict a disk partition's size to a maximum of 2.19 TB
(2.19 × 1012 byte
s) or 2 TiB
−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
(9.4 × 1021 bytes) or 8 ZiB
−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.
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.
(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
(LBA) in place of the historical cylinder-head-sector
(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
operating system
s reserve 16,384 bytes (or 32 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
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
. 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
(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.
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.
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.
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.
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.
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:
The term No native support on this arch and version. should be understood this way:
, also called x86-64
, 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
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
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.
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 MBRMaster 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 recordMaster 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 systemOperating 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.
| 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 partitionEFI 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.
| 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:
| 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-32IA-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 |
- 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.
- 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.
- 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.
- The GUID for
/usron Solaris is used as a generic GUID for ZFS by Mac OS X. - Definitions are in src/sys/sys/disklabel_gpt.h. NetBSD had used the FreeBSD GUIDs before unique NetBSD-specific GUIDs were created.
- Definitions are in http://www.chromium.org/chromium-os/chromiumos-design-docs/disk-format.
See also
- Master boot recordMaster boot recordA 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 IdentifierGlobally Unique IdentifierA 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 InterfaceExtensible Firmware InterfaceThe Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware...
(EFI) - Disk partitioningDisk partitioningDisk 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
- Microsoft TechNet: Disk Sectors on GPT Disks (Archived page)
- Microsoft TechNet: Troubleshooting Disks and File Systems
- Microsoft TechNet: Using GPT Drives
- Microsoft : FAQs on Using GPT disks in Windows
- Apple Developer Connection: Secrets of the GPT
- Make the most of large drives with GPT and Linux
- GPT fdisk : Information on Hybrid GPT-MBR, Converting MBR and BSD disklabels to GPT and Booting from GPT disks
- Convert Windows Vista SP1+ or 7 x86_64 boot from BIOS-MBR mode to UEFI-GPT mode without Reinstall
- Rod Smith - A BIOS to UEFI Transformation
- Support for GPT (Partition scheme) and HDD greater than 2.19 TB in Microsoft Windows XP
- Setting up a RAID volume in Linux with >2TB disks