Partition Type Numbers for FreeBSD and Linux, maybe Windows Gpart command
Partition Type Numbers for FreeBSD and Linux, maybe Windows Gpart command
Hexadecimal Codes for Partition Types
00 NO-Partition empty partition-table entry
01 DOS DOS 12-bit FAT
02 XENIX root file system
03 XENIX /usr file system (obsolete)
04 DOS 16-bit FAT (up to 32M)
05 Extended DOS 3.3+ extended partition
06 DOS 3.31+ Large File System (16-bit FAT, over 32M)
07 Advanced Unix
07 QNX QNX
07 OS/2 HPFS
07 WindowsNT NTFS
08 OS/2 (v1.0-1.3 only)
Updated: August 16, 2009 (2009.08.16); December 19, 2012 (2012.12.19); January 27, 2013 (2013.01.27).
Last Update: February 1, 2017 (2017.02.01).
Below a list of the known partition IDs (system indicators) of the various operating systems, file systems, boot managers, etc. For the various systems, short descriptions are given, in the cases where I have some info. There seem to be two other major such lists: Ralf Brown's (see interrupt list under Int 19) and Hale Landis' but the present one is more correct and more complete. (However, these two URLs are a valuable source for other information.) See also the old Powerquest table and the specification for DOS-type partition tables.
Copyright (C) Andries E. Brouwer 1995-2013. Link to this list - do not copy it. It is being updated regularly. Additions, corrections, explanations are welcome. (Mail to aeb@cwi.nl.)
The partition type (or partition ID) in a partition's entry in the partition table inside a master boot record (MBR) is a byte value intended to specify the file system the partition contains or to flag special access methods used to access these partitions (e.g. special CHS mappings, LBA access, logical mapped geometries, special driver access, hidden partitions, secured or encrypted file systems, etc.).
GUID Partition Table
The GUID Partition Table (GPT) is a standard for the layout of partition tables of a physical computer storage device, such as a hard disk drive or solid-state drive, using universally unique identifiers, which are also known as globally unique identifiers (GUIDs). Forming a part of the Unified Extensible Firmware Interface (UEFI) standard (Unified EFI Forum-proposed replacement for the PC BIOS), it is nevertheless also used for some BIOSs, because of the limitations of master boot record (MBR) partition tables, which use 32 bits for logical block addressing (LBA) of traditional 512-byte disk sectors.
All modern personal computer operating systems support GPT. Some, including macOS and Microsoft Windows on the x86 architecture, support booting from GPT partitions only on systems with EFI firmware, but FreeBSD and most Linux distributions can boot from GPT partitions on systems with either the BIOS or the EFI firmware interface.
History[edit]
The Master Boot Record (MBR) partitioning scheme, widely used since the early 1980s, imposed limitations for use of modern hardware. The available size for block addresses and related information is limited to 32 bits. For hard disks with 512‑byte sectors, the MBR partition table entries allow a maximum size of 2 TiB (2³² × 512‑bytes) or 2.20 TB (2.20 × 10¹² bytes).[1]
In the late 1990s, Intel developed a new partition table format as part of what eventually became the Unified Extensible Firmware Interface (UEFI). The GUID Partition Table is specified in chapter 5 of the UEFI 2.8 specification.[2] GPT uses 64 bits for logical block addresses, allowing a maximum disk size of 264 sectors. For disks with 512‑byte sectors, the maximum size is 8 ZiB (264 × 512‑bytes) or 9.44 ZB (9.44 × 10²¹ bytes).[1] For disks with 4,096‑byte sectors the maximum size is 64 ZiB (264 × 4,096‑bytes) or 75.6 ZB (75.6 × 10²¹ bytes).
In 2010, hard-disk manufacturers introduced drives with 4,096‑byte sectors (Advanced Format).[3] For compatibility with legacy hardware and software, those drives include an emulation technology (512e) that presents 512‑byte sectors to the entity accessing the hard drive, despite their underlying 4,096‑byte physical sectors.[4] Performance could be degraded on write operations, when the drive is forced to perform two read-modify-write operations to satisfy a single misaligned 4,096‑byte write operation.[5] Since April 2014, enterprise-class drives without emulation technology (4K native) have been available on the market.[6][7]
Readiness of the support for 4 KB logical sectors within operating systems differs among their types, vendors and versions.[8] For example, Microsoft Windows supports 4K native drives since Windows 8 and Windows Server 2012 (both released in 2012) in UEFI.[9]
Features[edit]
Like MBR, GPT uses logical block addressing (LBA) in place of the historical cylinder-head-sector (CHS) addressing. The protective MBR is stored at LBA 0, and the GPT header is in LBA 1, with a backup GPT header stored at the final LBA. The GPT header has a pointer to the partition table (Partition Entry Array), which is typically at LBA 2. Each entry on the partition table has a size of 128 bytes. The UEFI specification stipulates that a minimum of 16,384 bytes, regardless of sector size, are allocated for the Partition Entry Array.[10] Thus, on a disk with 512-byte sectors, at least 32 sectors are used for the Partition Entry Array, and the first usable block is at LBA 34 or higher, while on a 4,096-byte sectors disk, at least 4 sectors are used for the Partition Entry Array, and the first usable block is at LBA 6 or higher.
MBR variants[edit]
Protective MBR (LBA 0)[edit]
For limited backward compatibility, the space of the legacy Master Boot Record (MBR) is still reserved in the GPT specification, but it is now used in a way that prevents MBR-based disk utilities from misrecognizing and possibly overwriting GPT disks. This is referred to as a protective MBR.[11]
A single partition of type EEh, encompassing the entire GPT drive (where "entire" actually means as much of the drive as can be represented in an MBR), is indicated and identifies it as GPT. Operating systems and tools 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.[11] Furthermore, GPT-aware OSes may check the protective MBR and if the enclosed partition type is not of type EEh or if there are multiple partitions defined on the target device, the OS may refuse to manipulate the partition table.[12]
If the actual size of the disk exceeds the maximum partition size representable using the legacy 32-bit LBA entries in the MBR partition table, the recorded size of this partition is clipped at the maximum, thereby ignoring the rest of the disk. This amounts to a maximum reported size of 2 TiB, assuming a disk with 512 bytes per sector (see 512e). It would result in 16 TiB with 4 KiB sectors (4Kn), but since many older operating systems and tools are hard coded for a sector size of 512 bytes or are limited to 32-bit calculations, exceeding the 2 TiB limit could cause compatibility problems.[11]
Hybrid MBR (LBA 0 + GPT)[edit]
In operating systems that support GPT-based boot through BIOS services rather than EFI, the first sector may also still be used to store the first stage of the bootloader code, but modified to recognize GPT partitions. The bootloader in the MBR must not assume a sector size of 512 bytes.[11]
Partition table header (LBA 1)[edit]
| Offset | Length | Contents |
|---|---|---|
| 0 (0x00) | 8 bytes | Signature ("EFI PART", 45h 46h 49h 20h 50h 41h 52h 54h or 0x5452415020494645ULL[a] on little-endian machines) |
| 8 (0x08) | 4 bytes | Revision number of header - 1.0 (00h 00h 01h 00h) for UEFI 2.10 |
| 12 (0x0C) | 4 bytes | Header size in little endian (in bytes, usually 5Ch 00h 00h 00h or 92 bytes) |
| 16 (0x10) | 4 bytes | CRC32 of header (offset +0 to +0x5b) in little endian, with this field zeroed during calculation |
| 20 (0x14) | 4 bytes | Reserved; must be zero |
| 24 (0x18) | 8 bytes | Current LBA (location of this header copy) |
| 32 (0x20) | 8 bytes | Backup LBA (location of the other header copy) |
| 40 (0x28) | 8 bytes | First usable LBA for partitions (primary partition table last LBA + 1) |
| 48 (0x30) | 8 bytes | Last usable LBA (secondary partition table first LBA − 1) |
| 56 (0x38) | 16 bytes | Disk GUID in mixed endian[12] |
| 72 (0x48) | 8 bytes | Starting LBA of array of partition entries (usually 2 for compatibility) |
| 80 (0x50) | 4 bytes | Number of partition entries in array |
| 84 (0x54) | 4 bytes | Size of a single partition entry (usually 80h or 128) |
| 88 (0x58) | 4 bytes | CRC32 of partition entries array in little endian |
| 92 (0x5C) | * | Reserved; must be zeroes for the rest of the block (420 bytes for a sector size of 512 bytes; but can be more with larger sector sizes) |
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 (offsets 80 and 84 in the table).[2]: 119
Partition entries (LBA 2–33)[edit]
| Offset | Length | Contents |
|---|---|---|
| 0 (0x00) | 16 bytes | Partition type GUID (mixed endian[12]) |
| 16 (0x10) | 16 bytes | Unique partition GUID (mixed endian) |
| 32 (0x20) | 8 bytes | First LBA (little endian) |
| 40 (0x28) | 8 bytes | Last LBA (inclusive, usually odd) |
| 48 (0x30) | 8 bytes | Attribute flags (e.g. bit 60 denotes read-only) |
| 56 (0x38) | 72 bytes | Partition name (36 UTF-16LE code units) |
After the primary header and before the backup header, the Partition Entry Array describes partitions, using a minimum size of 128 bytes for each entry block.[13] The starting location of the array on disk, and the size of each entry, are given in the GPT header. The first 16 bytes of each entry designate the partition type's globally unique identifier (GUID). For example, the GUID for an EFI system partition is C12A7328-F81F-11D2-BA4B-00A0C93EC93B. The second 16 bytes are a GUID unique to the partition. Then follow the starting and ending 64 bit LBAs, partition attributes, and the 36 character (max.) Unicode partition name. As is the nature and purpose of GUIDs and as per RFC 4122, no central registry is needed to ensure the uniqueness of the GUID partition type designators.[14][2]: 2200
The 64-bit partition table attributes are shared between 48-bit common attributes for all partition types, and 16-bit type-specific attributes:
| Bit | Content |
|---|---|
| 0 | Platform required (required by the computer to function properly, OEM partition for example, disk partitioning utilities must preserve the partition as is) |
| 1 | EFI firmware should ignore the content of the partition and not try to read from it |
| 2 | Legacy BIOS bootable (equivalent to active flag (typically bit 7 set) at offset +0h in partition entries of the MBR partition table)[15] |
| 3–47 | Reserved for future use |
| 48–63 | Defined and used by the individual partition type |
Microsoft defines the type-specific attributes for basic data partition as:[16][17]
| Bit | Content |
|---|---|
| 60 | Read-only |
| 61 | Shadow copy (of another partition) |
| 62 | Hidden |
| 63 | No drive letter (i.e. do not automount) |
Google defines the type-specific attributes for ChromeOS kernel as:[18]
| Bit | Content |
|---|---|
| 56 | Successful boot flag |
| 55–52 | Tries remaining |
| 51–48 | Priority (15: highest, 1: lowest, 0: not bootable) |
Operating-system support[edit]
UNIX and Unix-like systems[edit]
| OS family | Version or edition | Platform | Read and write support | Boot support | Note |
|---|---|---|---|---|---|
| FreeBSD | Since 7.0 | IA-32, x86-64, ARM | Yes | Yes | In a hybrid configuration, both GPT and MBR partition identifiers may be used. |
| Linux | Most of the x86 Linux distributions Fedora 8+ and Ubuntu 8.04+[19] | IA-32, x86-64, ARM | Yes | Yes | Tools such as gdisk, GNU Parted,[20][21] util-linux v2.23+ fdisk,[22][23] SYSLINUX, GRUB 0.96 + patches and GRUB 2 have been GPT-enabled. Limited to 256 partitions per disk.[24] |
| macOS | Since 10.4.0 (some features since 10.4.6)[25] | IA-32, x86-64, PowerPC, Apple silicon | Yes | Yes | Only Intel and Apple silicon Macintosh computers can boot from GPT. |
| MidnightBSD | Since 0.4-CURRENT | IA-32, x86-64 | Yes | Requires CSM | In a hybrid configuration, both GPT and MBR partition identifiers may be used. |
| NetBSD | Since 6.0[26] | IA-32,[27] x86-64,[28] ARM | Yes | Yes | |
| OpenBSD | Since 5.9 | IA-32, x86-64, ARM | Yes | Yes | [29] |
| Solaris | Since Solaris 10 | IA-32, x86-64, SPARC | Yes | Yes | [30] |
| HP-UX | Since HP-UX 11.20 | IA-64 | Yes | Yes | [31] |
Windows: 32-bit versions[edit]
Windows 7 and earlier do not support UEFI on 32-bit platforms, and therefore do not allow booting from GPT partitions.[32]
| OS version | Release date | Platform | Read or write support | Boot support | Note |
|---|---|---|---|---|---|
| Windows 9x | 1995-08-24 | IA-32 | No[b] | No | |
| Windows XP | 2001-10-25 | IA-32 | No | No | |
| Windows Server 2003 | 2003-04-24 | IA-32 | No | No | |
| Windows Server 2003 SP1 | 2005-03-30 | IA-32 | Yes | No | MBR takes precedence in hybrid configuration. |
| Windows Vista | 2006-07-22 | IA-32 | Yes | No | MBR takes precedence in hybrid configuration. |
| Windows Server 2008 | 2008-02-27 | IA-32 | Yes | No | MBR takes precedence in hybrid configuration. |
| Windows 7 | 2009-10-22 | IA-32 | Yes | No | MBR takes precedence in hybrid configuration. |
| Windows 8 | 2012-08-01 | IA-32 | Yes | Requires UEFI[33] | MBR takes precedence in hybrid configuration. |
| Windows 8.1 | 2013-08-27 | IA-32 | Yes | Requires UEFI[34] | MBR takes precedence in hybrid configuration. |
| Windows 10 | 2015-07-29 | IA-32 | Yes | Requires UEFI[35] | MBR takes precedence in hybrid configuration. |
Windows: 64-bit versions[edit]
Limited to 128 partitions per disk.[32]
| OS version | Release date | Platform | Read and write support | Boot support | Note |
|---|---|---|---|---|---|
| Windows XP 64-Bit Edition for Itanium systems, Version 2002 | 2001-10-25 | IA-64 | Yes | Yes | MBR takes precedence in hybrid configuration. |
| Windows XP 64-Bit Edition, Version 2003 | 2003-03-28 | IA-64 | Yes | Yes | MBR takes precedence in hybrid configuration. |
| Windows XP Professional x64 Edition Windows Server 2003 | 2005-04-25[36] | x64 | Yes | No | MBR takes precedence in hybrid configuration. |
| Windows Server 2003 | 2005-04-25 | IA-64 | Yes | Yes | MBR takes precedence in hybrid configuration. |
| Windows Vista | 2006-07-22 | x64 | Yes | Requires UEFI[c] | MBR takes precedence in hybrid configuration. |
| Windows Server 2008 | 2008-02-27 | x64 | Yes | Requires UEFI | MBR takes precedence in hybrid configuration. |
| Windows Server 2008 | 2008-02-27 | IA-64 | Yes | Yes | MBR takes precedence in hybrid configuration. |
| Windows 7 | 2009-10-22 | x64 | Yes | Requires UEFI[d] | MBR takes precedence in hybrid configuration. |
| Windows Server 2008 R2 | 2009-10-22 | IA-64 | Yes | Yes | MBR takes precedence in hybrid configuration. |
| Windows 8 Windows Server 2012 | 2012-08-01 | x64 | Yes | Requires UEFI[37] | MBR takes precedence in hybrid configuration. |
| Windows 8.1 | 2013-08-27 | x64 | Yes | Requires UEFI[38] | MBR takes precedence in hybrid configuration. |
| Windows 10 | 2015-07-29 | x64 | Yes | Requires UEFI[39] | MBR takes precedence in hybrid configuration. |
| Windows Server 2016 | 2016-10-12 | x64 | Yes | Requires UEFI | MBR takes precedence in hybrid configuration. |
| Windows Server 2019 | 2018-10-02 | x64 | Yes | Requires UEFI | MBR takes precedence in hybrid configuration. |
| Windows Server 2022 | 2021-08-18[40] | x64 | Yes | Requires UEFI | MBR takes precedence in hybrid configuration. |
| Windows 11 | 2021-10-05 | x64, ARM64 | Yes | Yes | UEFI is a system requirement for Windows 11. |
Partition type GUIDs[edit]
"Partition type GUID" means that each partition type is strictly identified by a GUID number unique to that type, and therefore partitions of the same type will all have the same "partition type GUID". Each partition also has a "partition unique GUID" as a separate entry, which as the name implies is a unique id for each partition.
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