From 5149cb74af4c5c9d7ab5da98cfabc4862eb6cc16 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Sat, 29 Jan 2005 07:19:08 +0000 Subject: [PATCH] Add partition specification files. --- specs/partitions.text | 189 ++++ specs/partitions/index.html | 45 + specs/partitions/partition_types-1.html | 1085 +++++++++++++++++++++++ specs/partitions/partition_types-2.html | 644 ++++++++++++++ specs/partitions/partition_types.html | 45 + 5 files changed, 2008 insertions(+) create mode 100644 specs/partitions.text create mode 100644 specs/partitions/index.html create mode 100644 specs/partitions/partition_types-1.html create mode 100644 specs/partitions/partition_types-2.html create mode 100644 specs/partitions/partition_types.html diff --git a/specs/partitions.text b/specs/partitions.text new file mode 100644 index 0000000..619e69e --- /dev/null +++ b/specs/partitions.text @@ -0,0 +1,189 @@ +From Ralf Brown's Interrupt List, version 61: + + +Format of hard disk master boot sector: +Offset Size Description (Table 00650) + 00h 446 BYTEs Master bootstrap loader code +1BEh 16 BYTEs partition record for partition 1 (see #00651) +1CEh 16 BYTEs partition record for partition 2 +1DEh 16 BYTEs partition record for partition 3 +1EEh 16 BYTEs partition record for partition 4 +1FEh WORD signature, AA55h indicates valid boot block + +Format of partition record: +Offset Size Description (Table 00651) + 00h BYTE boot indicator (80h = active partition) + 01h BYTE partition start head + 02h BYTE partition start sector (bits 0-5) + 03h BYTE partition start track (bits 8,9 in bits 6,7 of sector) + 04h BYTE operating system indicator (see #00652) + 05h BYTE partition end head + 06h BYTE partition end sector (bits 0-5) + 07h BYTE partition end track (bits 8,9 in bits 6,7 of sector) + 08h DWORD sectors preceding partition + 0Ch DWORD length of partition in sectors +SeeAlso: #00650 + +(Table 00652) +Values for operating system indicator: + 00h empty partition-table entry + 01h DOS 12-bit FAT + 02h XENIX root file system + 03h XENIX /usr file system (obsolete) + 04h DOS 16-bit FAT (up to 32M) + 05h DOS 3.3+ extended partition + 06h DOS 3.31+ Large File System (16-bit FAT, over 32M) + 07h QNX + 07h OS/2 HPFS + 07h Windows NT NTFS + 07h Advanced Unix + 07h see partition boot record; could be any of the above or others + 08h OS/2 (v1.0-1.3 only) + 08h AIX bootable partition, SplitDrive + 08h Commodore DOS + 08h DELL partition spanning multiple drives + 09h AIX data partition + 09h Coherent filesystem + 0Ah OS/2 Boot Manager + 0Ah OPUS + 0Ah Coherent swap partition + 0Bh Windows95 with 32-bit FAT + 0Ch Windows95 with 32-bit FAT (using LBA-mode INT 13 extensions) + 0Eh logical-block-addressable VFAT (same as 06h but using LBA-mode INT 13) + 0Fh logical-block-addressable VFAT (same as 05h but using LBA-mode INT 13) + 10h OPUS + 11h OS/2 Boot Manager hidden 12-bit FAT partition + 12h Compaq Diagnostics partition + 14h (resulted from using Novell DOS 7.0 FDISK to delete Linux Native part) + 14h OS/2 Boot Manager hidden sub-32M 16-bit FAT partition + 16h OS/2 Boot Manager hidden over-32M 16-bit FAT partition + 17h OS/2 Boot Manager hidden HPFS partition + 17h hidden NTFS partition + 18h AST special Windows swap file ("Zero-Volt Suspend" partition) + 19h Willowtech Photon coS + 1Bh hidden Windows95 FAT32 partition + 1Ch hidden Windows95 FAT32 partition (using LBA-mode INT 13 extensions) + 1Eh hidden LBA VFAT partition + 20h Willowsoft Overture File System (OFS1) + 21h officially listed as reserved + 21h FSo2 + 23h officially listed as reserved + 24h NEC MS-DOS 3.x + 26h officially listed as reserved + 31h officially listed as reserved + 33h officially listed as reserved + 34h officially listed as reserved + 36h officially listed as reserved + 38h Theos + 3Ch PowerQuest PartitionMagic recovery partition + 40h VENIX 80286 + 41h Personal RISC Boot + 41h PowerPC boot partition + 42h SFS (Secure File System) by Peter Gutmann + 45h EUMEL/Elan + 46h EUMEL/Elan + 47h EUMEL/Elan + 48h EUMEL/Elan + 4Fh Oberon boot/data partition + 50h OnTrack Disk Manager, read-only partition + 51h OnTrack Disk Manager, read/write partition + 51h NOVELL + 52h CP/M + 52h Microport System V/386 + 53h OnTrack Disk Manager, write-only partition??? + 54h OnTrack Disk Manager (DDO) + 55h EZ-Drive (see also INT 13/AH=FFh"EZ-Drive") + 56h GoldenBow VFeature + 5Ch Priam EDISK + 61h SpeedStor + 63h Unix SysV/386, 386/ix + 63h Mach, MtXinu BSD 4.3 on Mach + 63h GNU HURD + 64h Novell NetWare 286 + 64h SpeedStore + 65h Novell NetWare (3.11) + 67h Novell + 68h Novell + 69h Novell + 70h DiskSecure Multi-Boot + 71h officially listed as reserved + 73h officially listed as reserved + 74h officially listed as reserved + 75h PC/IX + 76h officially listed as reserved + 7Eh F.I.X. + 80h Minix v1.1 - 1.4a + 81h Minix v1.4b+ + 81h Linux + 81h Mitac Advanced Disk Manager + 82h Linux Swap partition + 82h Prime + 82h Solaris (Unix) + 83h Linux native file system (ext2fs/xiafs) + 84h OS/2-renumbered type 04h partition (related to hiding DOS C: drive) + 85h Linux EXT + 86h FAT16 volume/stripe set (Windows NT) + 87h HPFS Fault-Tolerant mirrored partition + 87h NTFS volume/stripe set + 93h Amoeba file system + 94h Amoeba bad block table + 98h Datalight ROM-DOS SuperBoot + 99h Mylex EISA SCSI + A0h Phoenix NoteBIOS Power Management "Save-to-Disk" partition + A1h officially listed as reserved + A3h officially listed as reserved + A4h officially listed as reserved + A5h FreeBSD, BSD/386 + A6h OpenBSD + A9h NetBSD (http://www.netbsd.org/) + B1h officially listed as reserved + B3h officially listed as reserved + B4h officially listed as reserved + B6h officially listed as reserved + B6h Windows NT mirror set (master), FAT16 file system + B7h BSDI file system (secondarily swap) + B7h Windows NT mirror set (master), NTFS file system + B8h BSDI swap partition (secondarily file system) + BEh Solaris boot partition + C0h DR DOS/DR-DOS/Novell DOS secured partition + C0h CTOS + C1h DR DOS 6.0 LOGIN.EXE-secured 12-bit FAT partition + C4h DR DOS 6.0 LOGIN.EXE-secured 16-bit FAT partition + C6h DR DOS 6.0 LOGIN.EXE-secured Huge partition + C6h corrupted FAT16 volume/stripe set (Windows NT) + C6h Windows NT mirror set (slave), FAT16 file system + C7h Syrinx Boot + C7h corrupted NTFS volume/stripe set + C7h Windows NT mirror set (slave), NTFS file system + CBh Reserved for DR DOS/DR-DOS/OpenDOS secured FAT32 + CCh Reserved for DR DOS/DR-DOS secured FAT32 (LBA) + CEh Reserved for DR DOS/DR-DOS secured FAT16 (LBA) + D0h Multiuser DOS secured FAT12 + D1h Old Multiuser DOS secured FAT12 + D4h Old Multiuser DOS secured FAT16 (<= 32M) + D5h Old Multiuser DOS secured extended partition + D6h Old Multiuser DOS secured FAT16 (> 32M) + D8h CP/M-86 + DBh CP/M, Concurrent CP/M, Concurrent DOS + DBh CTOS (Convergent Technologies OS) + E1h SpeedStor 12-bit FAT extended partition + E2h DOS read-only (Florian Painke's XFDISK 1.0.4) + E3h DOS read-only + E3h Storage Dimensions + E4h SpeedStor 16-bit FAT extended partition + E5h officially listed as reserved + E6h officially listed as reserved + EBh BeOS BFS (BFS1) + F1h Storage Dimensions + F2h DOS 3.3+ secondary partition + F3h officially listed as reserved + F4h SpeedStor + F4h Storage Dimensions + F5h Prologue + F6h officially listed as reserved + FEh LANstep + FEh IBM PS/2 IML (Initial Microcode Load) partition + FFh Xenix bad block table +Note: for partition type 07h, one should inspect the partition boot record + for the actual file system type +SeeAlso: #00651 diff --git a/specs/partitions/index.html b/specs/partitions/index.html new file mode 100644 index 0000000..cb20a5e --- /dev/null +++ b/specs/partitions/index.html @@ -0,0 +1,45 @@ + + + + + Partition types + + + + + +Next +Previous +Contents +
+

Partition types

+ +

Andries Brouwer, aeb@cwi.nl

2004-12-12 +

+

1. List of partition identifiers for PCs

+ +

+

2. Properties of partition tables.

+ + +
+Next +Previous +Contents + + diff --git a/specs/partitions/partition_types-1.html b/specs/partitions/partition_types-1.html new file mode 100644 index 0000000..179f07e --- /dev/null +++ b/specs/partitions/partition_types-1.html @@ -0,0 +1,1085 @@ + + + + + Partition types: List of partition identifiers for PCs + + + + + +Next +Previous +Contents +
+

1. List of partition identifiers for PCs

+ +

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 +Powerquest table +and the +specification for DOS-type partition tables. +

Copyright (C) Andries E. Brouwer 1995-2004. +Link to this list - do not copy it. +It is being updated regularly. +Additions, corrections, explanations are welcome. +(Mail to +aeb@cwi.nl.) +

+

+

+

ID Name

+

+

00 Empty

To be precise: this is not used to designate unused area +on the disk, but marks an unused partition table entry. +(All other fields should be zero as well.) +Unused area is not designated. +Plan9 +assumes that it can use everything not claimed for other systems +in the partition table. +

+

01 DOS 12-bit FAT

DOS is a family of single-user operating systems for PCs. +86-DOS (`QDOS' - Quick and Dirty OS) was a CP/M-like operating +system written by Tim Paterson of Seattle Computer Products (1979). +Microsoft bought it, renamed it to MS-DOS 1.0 and sold it to IBM (1980) +to be delivered together with the first IBM PCs (1981). +MS-DOS 2.0 (1983) was rather different, and designed to be somewhat +Unix-like. It supported a hard disk (up to 16MB; up to 32MB for version 2.1). +Version 3.3+ added the concept of partitions, where each partition is +at most 32MB. (Compaq DOS 3.31 relaxed this restriction.) +Since version 4.0 partitions can be 512 MB. +Version 5.0 supports partitions up to 2 GB. +Several clones exist: +DR-DOS +(from Digital Research, later part of Novell and called NovellDOS or +NDOS, +then owned by Caldera and called +OpenDOS, +then by its subsidiary Lineo who named it back to DR-DOS. +See +http://www.drdos.com/), +PC-DOS +(from IBM), +FreeDOS, ... +See +Types of DOS. +See comp.os.msdos.* and +MSDOS partitioning summary. +The type 01 is for partitions up to 15 MB. +

+

02 XENIX root

+

+

03 XENIX /usr

Xenix is an old port of Unix V7. +Microsoft Xenix OS was announced August 1980, a portable and commercial +version of the Unix operating system for the Intel 8086, Zilog Z8000, +Motorola M68000 and Digital Equipment PDP-11. +Microsoft introduces XENIX 3.0 in April 1983. +( +Timeline of Microcomputers) +SCO delivered its first Xenix for 8088/8086 in 1983. +See comp.unix.xenix.sco. +

+

04 DOS 3.0+ 16-bit FAT (up to 32M)

Matthias Paul writes: Some old DOS versions have had a bug which requires this +partition to be located in the 1st physical 32 MB of the hard disk, hence +for compatibility with these old issues, partitions located elsewhere +should better be assigned the ID FAT16B (06h). +

+

05 DOS 3.3+ Extended Partition

Supports at most 8.4 GB disks: with type 05 DOS/Windows will not use +the extended BIOS call, even if it is available. See type 0f below. +Using type 05 for extended partitions beyond 8 GB may lead +to data corruption with MSDOS. +

An extended partition is a box containing a linked list of logical +partitions. This chain (linked list) can have arbitrary length, but +some FDISK versions refuse to make more logical partitions than there +are drive letters available (e.g. MS-DOS LASTDRIVE=26 is good for at +most 24 disk partitions; Novell DOS 7+ allows LASTDRIVE=32). +

+

06 DOS 3.31+ 16-bit FAT (over 32M)

Partitions, or at least the FAT16 filesystems created on them, +are at most 2 GB for DOS and Windows 95/98 (at most 65536 clusters, +each at most 32 KB). +Windows NT can create up to 4 GB FAT16 filesystems (using 64 KB clusters), +but these cause problems for DOS and Windows 95/98. +Note that VFAT is 16-bit FAT with long filenames; FAT32 is a different +filesystem. +

+

07 OS/2 IFS (e.g., HPFS)

IFS = Installable File System. The best known example is HPFS. +OS/2 will only look at partitions with ID 7 for any installed +IFS (that's why the EXT2.IFS packet includes a special "Linux +partition filter" device driver to fool OS/2 into thinking Linux +partitions have ID 07). (Kai Henningsen (kai@khms.westfalen.de)) +

+

07 Windows NT NTFS

It is rumoured that the Windows NT boot partition must be primary, +and within the first 2 GB of the disk. +

+

07 Advanced Unix

+

+

07 QNX2.x pre-1988 (see below under IDs 4d-4f)

+

+

08 OS/2 (v1.0-1.3 only)

+

+

08 AIX boot partition

+

+

08 SplitDrive

+

+

08 Commodore DOS

Matthias Paul writes: "This indicates a Commodore MS-DOS 3.x +logically sectored FAT partition." +

+

08 DELL partition spanning multiple drives

+

+

08 QNX 1.x and 2.x ("qny")

(according to +QNX Partitions) +

+

09 AIX data partition

Some reports interchange AIX boot & data. +AIX is IBM's version of Unix. See comp.unix.aix. +

+

09 Coherent filesystem

Coherent was a UNIX-type OS for the 286-386-486, marketed by +Mark Williams Company led by Bob Swartz, renowned for its good +documentation. It was introduced in 1980 and died 1 Feb 1995. +The last versions are V3.2 for 286-386-486 and V4.0 +(May 1992, using protected mode) for 386-486 only. +It sold for $99 a copy, and the FAQ says that 40000 copies have been sold. +See comp.os.coherent and +this page. +A Coherent partition has to be primary. +

+

09 QNX 1.x and 2.x ("qnz")

(according to +QNX Partitions) +

+

0a OS/2 Boot Manager

OS/2 is the operating system designed by Microsoft and IBM to be +the successor of MS-DOS. Dropped by Microsoft. See comp.os.os2. +Windows 2000 actively tries to destroy OS/2 Boot Manager. +See +below. +

+

0a Coherent swap partition

+

+

0a OPUS

Open Parallel Unisys Server. +See +Unisys. +

+

0b WIN95 OSR2 FAT32

Partitions up to 2047GB. See +Partition Types

+

0c WIN95 OSR2 FAT32, LBA-mapped

Extended-INT13 equivalent of 0b. +

+

0e WIN95: DOS 16-bit FAT, LBA-mapped

+

+

0f WIN95: Extended partition, LBA-mapped

Windows 95 uses 0e and 0f as the extended-INT13 equivalents +of 06 and 05. +For the problems this causes, see +Windows 95 fdisk problems and +Possible data loss with LBA and INT13 extensions. +(Especially when going back and forth between MSDOS and Windows 95, +strange things may happen with a type 0e or 0f partition.) +Windows NT does not recognize the four W95 types 0b, 0c, +0e, 0f +( +Win95 Partition Types Not Recognized by Windows NT). +DRDOS 7.03 does not support this type (but DRDOS 7.04 does). +

+

10 OPUS (?)

Maybe decimal, for type 0a. +

+

11 Hidden DOS 12-bit FAT

When it boots a DOS partition, OS/2 Boot Manager will hide +all primary DOS partitions except the one that is booted, +by changing its ID: 01, 04, 06 becomes +11, 14, 16. Also 07 becomes 17. +

+

11 Leading Edge DOS 3.x +logically sectored FAT

(According to Matthias Paul.) +

+

12 Configuration/diagnostics partition

ID 12 (decimal 18) is used by Compaq for their configuration utility +partition. It is a FAT-compatible partition (about 6 MB) that boots +into their utilities, and can be added to a LILO menu as if it were MS-DOS. +(David C. Niemi) +Stephen Collins reports a 12 MB partition with ID 12 on a Compaq 7330T. +Tigran A. Aivazian reports a 40 MB partition with ID 12 on a +64 MB Compaq Proliant 1600. +ID 12 is used by the Compaq Contura to denote its hibernation partition. +(dan@fch.wimsey.bc.ca) +

NCR has used ID 0x12 MS-DOS partitions for diagnostics and +firmware support on their WorldMark systems since the mid-90s. +DataLight's ROM-DOS has replaced MS-DOS on more recent systems. +Partition sizes were once 72M (MS-DOS) but are now 40M (ROM-DOS). +

Intel has begun offering ROM-DOS based "Service Partition" support +on many OEM systems. This support initially used ID 0x98 but has +recently changed to ID 0x12. Intel provides their own support for +this partition in the form of a System Resource CD. Partition size +has remained constant at 40M. See e.g. +sds2.pdf. +(Chuck Rouillard) +

+

14 Hidden DOS 16-bit FAT <32M

(Ralf Brown's interrupt list adds: `ID 14 resulted from using Novell +DOS 7.0 FDISK to delete Linux Native partition') +

+

14 AST DOS with +logically sectored FAT

AST MS-DOS 3.x was an OEM version supporting 8 instead of the usual 4 +partition entries in the MBR. These special MBRs can be detected +by another signature in the MBR stored in front of the partition table. +

+

16 Hidden DOS 16-bit FAT >=32M

+

+

17 Hidden IFS (e.g., HPFS)

+

+

18 AST SmartSleep Partition

Ascentia laptops have a `Zero Volt Suspend Partition' +or `SmartSleep Partition' of size 2MB+memory size. +See +AST. +Ralf Brown calls this the "AST Windows swapfile". +

+

19 Unused

Claimed for Willowtech Photon coS (completely optimized system) +by Willow Schlanger willow@dezine.net. See dejanews. +

+

1b Hidden WIN95 OSR2 FAT32

+

+

1c Hidden WIN95 OSR2 FAT32, LBA-mapped

+

+

1e Hidden WIN95 16-bit FAT, LBA-mapped

+

+

20 Unused

Rumoured to be used by Willowsoft Overture File System (OFS1), +if there is such a thing. +

+

21 Reserved

(according to +delorie). And +Powerquest +writes `Officially listed as reserved (HP Volume Expansion, +SpeedStor variant)'. See also ID a1.) +

+

21 Unused

Claimed for FSo2 (Oxygen File System) by Dave Poirier +(ekstazya@sprint.ca). +See dejanews. +

+

22 Unused

Claimed for Oxygen Extended Partition Table by ekstazya@sprint.ca. +See dejanews. +

+

23 Reserved

+

+

24 NEC DOS 3.x

This is NEC MS-DOS 3.30 +logically sectored FAT. +Similar to type 14 above, the MBR could have up to 8 +partition entries. +

+

26 Reserved

+

+

2a AtheOS File System (AFS)

AtheOS is an open source operating system written by Kurt Skauen. +It is dead now - for a single page, see +www.atheos.cx or +sourceforge. +For the history, see +wikipedia. +When progress seemed to stop, the project forked and the +Syllable OS +was started by Kristian van der Vliet (2002). See also +wikipedia. +It uses the same filesystem, AthFS or AFS, an extension of BeFS, the +filesystem of BeOS. There is an attempt at a Linux driver at +sourceforge. +

+

2b SyllableSecure (SylStor)

A variation on AthFS is +Sylstor, +with added security. +

+

31 Reserved

+

+

32 NOS

Simon Butcher (simonb@alien.net.au) writes: +This type is being used by an operating system being developed +by Alien Internet Services in Melbourne Australia called NOS. +The id '32' was chosen not only because it's one of the few +that are left available, but 32k is the size of the +EEPROM the OS was originally targetted for. +

+

33 Reserved

+

+

34 Reserved

+

+

35 JFS on OS/2 or eCS

David van Enckevort (david@mensys.nl) writes: +Type 0x35 is used by OS/2 Warp Server for e-Business, +OS/2 Convenience Pack (aka version 4.5) and +eComStation +(eCS, an OEM version of OS/2 Convenience Pack) for the OS/2 implementation +of JFS (IBM AIX Journaling Filesystem). +Since JFS is a non-bootable file system, you cannot install eCS +to a JFS partition. +

+

36 Reserved

+

+

38 THEOS ver 3.2 2gb partition

+

+

39 Plan 9 partition

+Plan 9 +is an operating system developed at Bell Labs for many architectures. +Source is available. See comp.os.plan9. +Originally Plan 9 used an unallocated portion at the end of the disk. +Plan 9 3rd edition uses partitions of +type 0x39, subdivided into subpartitions described in +the Plan 9 partition table in the second sector of the partition. +

+

39 THEOS ver 4 spanned partition

+

+

3a THEOS ver 4 4gb partition

+

+

3b THEOS ver 4 extended partition

THEOS is a multiuser multitasking OS for PCs founded by Timothy Williams +in 1983. Current release 4.0, previous release 3.2. They say about +themselves: `THEOS with over 150,000 customers and over 1,000,000 users +around the world brings a mainframe look and feel to computers +without the complexity and high maintenance costs. +Hundreds of applications exist with networking and Windows integration.' +See +the Theos home page

+

3c PartitionMagic recovery partition

Cody Batt (codyb@powerquest.com) writes: +When a +PowerQuest +product like +PartitionMagic or +Drive Image makes changes to the disk, +it first changes the type flag to 0x3C so that the OS won't try to +modify it etc. At the end of the process, it gets changed back to +what it was at first. So, the only time you should see a 0x3C type flag +is if the process was interrupted somehow (power outage, user reboot etc). +If you change it back manually with a partition table editor or something +then most of the time everything is okay. +

+

3d Hidden NetWare

According to +Powerquest. +

+

40 Venix 80286

A very old Unix-like operating system for PCs. +

+

41 Linux/MINIX (sharing disk with DRDOS)

Very old FAQs recommended to use 41 etc instead of 81 etc +on a disk shared with DRDOS because DRDOS allegedly disregards +the high order bit of the partition type. +These types are not used anymore today. +Roger Wolff (R.E.Wolff@BitWizard.nl) confirms: +I remember installing DRDOS, and getting a few extra drive letters +that I didn't expect. Turns out those are my Minix partitions. +It is looking at them as a FAT filesystem. Looks like a big mess. +After finding no other possibility than to just "not touch those drive +letters" I continue with the install. After a few minutes DRDOS +automatically decides to write a copy of the FAT into a file on one +of my MINIX partitions. Bye bye Minix partition. +

+

41 Personal RISC Boot

+

+

41 PPC PReP (Power PC Reference Platform) Boot

+

+

42 Linux swap (sharing disk with DRDOS)

+

+

42 SFS (Secure Filesystem)

SFS is an encrypted filesystem driver for DOS on 386+ PCs, written +by Peter Gutmann. +

+

42 Windows 2000 dynamic extended partition marker

If a partition table entry of type 0x42 is present in the legacy +partition table, then W2K ignores the legacy partition table +and uses a proprietary partition table and a proprietary partitioning +scheme (LDM or DDM). As the Microsoft KnowledgeBase writes: +Pure dynamic disks (those not containing any +hard-linked partitions) have only a single +partition table entry (type 42) to define the +entire disk. Dynamic disks store their volume +configuration in a database located in a 1-MB +private region at the end of each dynamic disk. +

+

43 Linux native (sharing disk with DRDOS)

+

+

44 GoBack partition

+GoBack +is a utility that records changes made to the disk, +allowing you to view or go back to some earlier state. +It takes over disk I/O like a Disk Manager would, +and stores its logs in its own partition. +

+

45 Boot-US boot manager

Ulrich Straub (ustraub@boot-us.de) writes: +The boot manager can be installed to MBR, a separate primary partition or +diskette. When installed to a primary partition this partition gets +the ID 45h. This partition does not contain a file system, it contains +only the boot manager and occupies a single cylinder (below 8 GB). +See +www.boot-us.com. +

+

45 Priam

According to +Powerquest. +See also ID 5c. +

+

45 EUMEL/Elan

+

+

46 EUMEL/Elan

+

+

47 EUMEL/Elan

+

+

48 EUMEL/Elan

Eumel, and later Ergos L3, are multiuser multitasking systems +developed by Jochen Liedtke at GMD. +It was used at German schools for the computer science education. +( +Elan was the programming language used.) +

+

4a Mark Aitchison's ALFS/THIN lightweight filesystem for DOS

According to +Powerquest. +

+

4a AdaOS Aquila (Withdrawn)

Nick Roberts at some point in time announced that he would use 4a +for Aquila, but now plans to use the AODPS 7f. +

+

4c Oberon partition

See +http://www.oberon.ethz.ch/betadocu.html. +This partition type (decimal 76) is used for the Aos filesystem. +Type 4f is used for the Nat filesystem. +One may have several partitions of this type. +

+

4d QNX4.x

+

+

4e QNX4.x 2nd part

+

+

4f QNX4.x 3rd part

QNX is a POSIX-certified, microkernel, distributed, fault-tolerant +OS for the 386 and up, including support for the 386EX in embedded +applications. For info see +http://www.qnx.com/ or +ftp.qnx.com. +See also comp.os.qnx. +ID 7 is outdated - QNX2 used 07, QNX4.x uses 77, +and optionally 78 and 79 for additional QNX partitions +on a single drive. +These values 77, 78, 79 seem to be the decimal values in view of +QNX Partitions and +Neutrino filesystems. +

+

4f Oberon partition

See +http://www.oberon.ethz.ch/native/. +(The partition ID is given in +this posting in comp.lang.oberon. The +install instructions say that at most one partition +can have this type (decimal 79), and that one needs a different type, +like 50 (decimal 80) for a second Oberon system. Moreover, that users +of System Commander must avoid types containing the 0x10 bit.) +See also type 4c (decimal 76) above. +

+

50 OnTrack Disk Manager (older versions) RO

Disk Manager is a program of OnTrack, to enable people to use +IDE disks that are larger than 504MB under DOS. +For info see +http://www.ontrack.com. +Linux kernel versions older than 1.3.14 do not coexist with DM. +

+

50 Lynx RTOS

"Beginning with version 3.0, LynxOS gives users the ability to +place up to 14 partitions of 2 GB each on both SCSI and IDE drives, +for a total of up to 28 GB of file system space." +See +www.lynuxworks.com. +

+

50 Native Oberon (alt)

+

+

51 OnTrack Disk Manager RW (DM6 Aux1)

+

+

51 Novell

+

+

52 CP/M

+

+

52 Microport SysV/AT

+

+

53 Disk Manager 6.0 Aux3

+

+

54 Disk Manager 6.0 Dynamic Drive Overlay (DDO)

+

+

55 EZ-Drive

EZ-Drive is another disk manager (by MicroHouse, 1992). +Linux kernel versions older than 1.3.29 do not coexist with EZD. +(On 990323 MicroHouse International was acquired by EarthWeb; +MicroHouse Solutions split off and changed its name into +StorageSoft. +MicroHouse Development split off and changed its name into +ImageCast. +It is StorageSoft that now markets EZDrive and DrivePro.) +

+

56 Golden Bow VFeature Partitioned Volume.

This is a Non-Standard DOS Volume. +(Disk Manager type utility software) +

+

56 DM converted to EZ-BIOS

+

56 AT&T MS-DOS 3.x +logically sectored FAT.

+

57 DrivePro

Doug Anderson (DougA@ImageCast.com), with his brother Steve cofounder +of MicroHouse (1989), writes: We actually use three different partition types: +$55: `StorageSoft EZ-BIOS' - EZ-Drive, Maxtor, MaxBlast, and DriveGuide install +this type if the drive needs to be handled by our INT13 redirector. +$56: `StorageSoft EZ-BIOS DM Conversion' - Same as $55 but used +when a DiskManager "skewed" partition has been converted to EZ-BIOS. +$57: `StorageSoft DrivePro' - Used by our DrivePro product. +

+

57 VNDI Partition

(According to disk.c in the Netware source. +Not in actual use.) +

+

5c Priam EDisk

Priam EDisk Partitioned Volume. +This is a Non-Standard DOS Volume. +(Disk Manager type utility software) +

+

61 SpeedStor

Storage Dimensions SpeedStor Volume. +This is a Non-Standard DOS Volume. +(Disk Manager type utility software) +

+

63 Unix System V (SCO, ISC Unix, UnixWare, ...), Mach, GNU Hurd

A Unixware 7.1 partition must start below the 4GB limit. +(If the /stand/stage3.blm is located past this limit, booting +will fail with "FATAL BOOT ERROR: Can't load stage3".) +

+

64 PC-ARMOUR protected partition

Used by PC-ARMOUR, a disk protection by Dr. A.Solomon, +intended to keep the disk inaccessible until the right +password was given (and then an int13 hook was loaded +above top-of-memory that showed c/h/s 0/0/2, with a copy +of the real partition table, when 0/0/1 was requested). +(loekw@worldonline.nl) +

+

64 Novell Netware 286, 2.xx

+

+

65 Novell Netware 386, 3.xx or 4.xx

(Novell Netware used to be the main Network Operating System available. +Netware 68 or S-Net (1983) was for a Motorola 68000, +Netware 86 for an Intel 8086 or 8088. +Netware 286 was for an Intel 80286 and existed in various +versions that were later merged to Netware 2.2. +Netware 386 was a rewrite in C for the Intel 386, +later renamed 3.x - it existed at least in versions +3.0, 3.1, 3.10, 3.11, 3.12. Its successor Netware 4.xx had +versions 4.00, 4.01, 4.02, 4.10, 4.11. Then came Intranetware.) +Netware >= 3.0 uses one partition per drive. It allocates +logical Volumes inside these partitions. The volumes can be +split over several drives. The filesystem used is called +"Turbo FAT"; it only very vaguely resembles the DOS FAT file system. +(Kai Henningsen (kai@khms.westfalen.de)) +

+

66 Novell Netware SMS Partition

According to disk.c in the Netware source. +SMS: Storage Management Services. No longer used. +

+

67 Novell

Roman Gruber reports: this code has frozen my version of norton disk-editor +(so I think it has to be something special). +Jeff Merkey says: 67 is for Wolf Mountain. +

+

68 Novell

+

+

69 Novell Netware 5+, Novell Netware NSS Partition

According to disk.c in the Netware source. +NSS = Novell Storage Services. +

+

6e ??

+Reported once.

+

70 DiskSecure Multi-Boot

+

+

71 Reserved

+

+

73 Reserved

+

+

74 Reserved

+

+

74 Scramdisk partition

+Scramdisk +is freeware and shareware disk encryption software. +It supports container files, dedicated partitions (type 0x74) and +disks hidden in WAV audio files. +(Shaun Hollingworth (moatlane@btconnect.com)) +

+

75 IBM PC/IX

+

+

76 Reserved

+

+

77 M2FS/M2CS partition

Jeff Merkey writes: 77 is one we are using internally for M2FS/M2CS partitions. +

+

77 VNDI Partition

(According to disk.c in the Netware source. Not in actual use.) +

+

78 XOSL FS

XOSL Bootloader filesystem, see +www.xosl.org. +

+

7e Unused

Claimed for F.I.X. by gruberr@kapsch.net. See dejanews. +

+

7f Unused

Proposed for the +Alt-OS-Development Partition Standard. +

+

80 MINIX until 1.4a

+

+

81 MINIX since 1.4b, early Linux

Minix is a Unix-like operating system written by Andy Tanenbaum +and students at the Vrije Universiteit, Amsterdam, around 1989-1991. +It runs on PCs (8086 and up), MacIntosh, Atari, Amiga, Sparc. +Ref: Operating Systems: Design and Implementation, Andrew S. Tanenbaum, +Prentice-Hall, ISBN 0-13-637406-9 +Since 950601 Minix is freely available - site: +ftp.cs.vu.nl. +See also comp.os.minix. +

+

81 Mitac disk manager

+

+

82 Prime

+

+

82 Solaris x86

Solaris creates a single partition with id 0x82, then uses Sun disk labels +within the partition to split it further. +(Brandon S. Allbery (allbery@kf8nh.apk.net)) +Starting from 2005, newly installed systems will use 0xbf. +

+

82 Linux swap

+

+

83 Linux native partition

Linux is a Unix-like operating system written by Linus Torvalds +and many others on the internet since Fall 1991. +It runs on PCs (386 and up) and a variety of other hardware. +It is distributed under GPL. +Software can be found numerous places, like ftp.funet.fi, +metalab.unc.edu and tsx-11.mit.edu. +See also comp.os.linux.* and +http://www.linux.org/. +Various filesystem types like xiafs, ext2, ext3, reiserfs, etc. +all use ID 83. Some systems mistakenly assume that 83 must mean ext2. +

+

84 OS/2 hidden C: drive

OS/2-renumbered type 04 partition. +

+

84 Hibernation partition

(following Appendix E of the Microsoft APM 1.1f specification). +Reported for various laptop models. +E.g., used on Dell Latitudes (with Dell BIOS) that use the MKS2D utility. +APM 1.2 hibernation partitions can be used by Windows 98 or higher. +

+

85 Linux extended partition

+

+

86 Old Linux RAID partition superblock

See fd. +

+

86 NTFS volume set

Legacy Fault Tolerant FAT16 volume. +Windows NT 4.0 or earlier will add 0x80 to the partition type +for partitions that are part of a Fault Tolerant set (mirrored +or in a RAID-5 volume). Thus, one gets types 86, 87, +8b, 8c. See also +Windows NT Boot Process and Hard Disk Constraints. +

+

87 NTFS volume set

Legacy Fault Tolerant NTFS volume. +HPFS Fault-Tolerant mirrored partition. +

+

88 Linux plaintext partition table

+

+

8a Linux Kernel Partition (used by AiR-BOOT)

Martin Kiewitz (KiWi@vision.fido.de) writes: +I'm currently writing a pretty nice boot-loader. +For this I'm using Linux Boot Loader ID A0h, and partitition +type 8Ah for the partition holding the kernel image. +

+

8b Legacy Fault Tolerant FAT32 volume

+

+

8c Legacy Fault Tolerant FAT32 volume using BIOS extd INT 13h

+

+

8d Free FDISK hidden Primary DOS FAT12 partitition

+Free FDISK is the +FDISK used by +FreeDOS. +It hides types 01, 04, 05, 06, +0b, 0c, 0e, 0f by adding +decimal 140 (0x8c). +

+

8e Linux Logical Volume Manager partition

See +pvcreate(8) as found under +http://linux.msede.com/lvm. +(For a while this was 0xfe.) +

+

90 Free FDISK hidden Primary DOS FAT16 partitition

+

+

91 Free FDISK hidden DOS extended partitition

+

+

92 Free FDISK hidden Primary DOS large FAT16 partitition

+

+

93 Hidden Linux native partition

+

+

93 Amoeba

+

+

94 Amoeba bad block table

Amoeba is a distributed operating system written by Andy Tanenbaum, +together with Frans Kaashoek, Sape Mullender, Robert van Renesse +and others since 1981. +It runs on PCs (386 and up), Sun3, Sparc, 68030. +It is free for universities for research/teaching purposes. +For information, see +ftp.cs.vu.nl. +

+

95 MIT EXOPC native partitions

+http://www.pdos.lcs.mit.edu/exo/ +(Andrew Purtell, Andrew_Purtell@NAI.com) +

+

97 Free FDISK hidden Primary DOS FAT32 partitition

+

+

98 Free FDISK hidden Primary DOS FAT32 partitition (LBA)

+

+

98 Datalight ROM-DOS Super-Boot Partition

See +www.datalight.com, and type 12 above. +

+

99 DCE376 logical drive

No, it's not a hibernation partition; it's closest to a DOS extended +partition. It's used by the Mylex DCE376 EISA SCSI adaptor for partitions +which are beyond the 1024th cylinder of a drive. I've only seen references +to type 99 with the DCE376. +(Christian Carey, ccarey@CapAccess.ORG) +

+

9a Free FDISK hidden Primary DOS FAT16 partitition (LBA)

+

+

9b Free FDISK hidden DOS extended partitition (LBA)

+

+

9f BSD/OS

Current sysid for BSDI. The types b7 and b8 given below +are for an older version of the filesystem used in pre-v3.0 versions of the OS. +These days the system is v4.1 BSD/OS. +BSDI reports 2.1 million installed servers and 12 million licenses sold. +See +http://www.bsdi.com/. +

+

a0 Laptop hibernation partition

Reported for various laptops like IBM Thinkpad, Phoenix NoteBIOS, Toshiba +under names like zero-volt suspend partition, suspend-to-disk partition, +save-to-disk partition, power-management partition, hibernation partition. +Usually at the start or end of the disk area. +(This is also the number used by Sony on the VAIO. Recent VAIOs +can also hibernate to a file in the filesystem, +the choice being made from the BIOS setup screen.) +

+

a1 Laptop hibernation partition

Reportedly used as "Save-to-Disk" partition on a NEC 6000H notebook. +Types a0 and a1 are used on systems with Phoenix BIOS; +the Phoenix PHDISK utility is used with these. +

+

a1 HP Volume Expansion (SpeedStor variant)

IDs 21, a1, a3, a4, a6, b1, b3, b4, b6 are for HP Volume Expansion +(SpeedStor variant). +

+

a3 HP Volume Expansion (SpeedStor variant)

+

+

a4 HP Volume Expansion (SpeedStor variant)

+

+

a5 BSD/386, 386BSD, NetBSD, FreeBSD

386BSD is a Unix-like operating system, a port of 4.3BSD Net/2 +to the PC done by Bill Jolitz around 1991. When Jolitz seemed to +stop development, an updated version was called FreeBSD (1992). +The outcome of a Novell vs. UCB law suit was that Net/2 contained +AT&T code, and hence was not free, but that 4.4BSD-Lite was free. +After that, FreeBSD and NetBSD were restructured, and FreeBSD 2.0 +and NetBSD 1.0 are based on 4.4BSD-Lite. +FreeBSD runs on PCs. See +http://www.freebsd.org/FreeBSD.html. +For NetBSD, see below - it changed partition type to a9. +386BSD seems to be dead now. The kernel source is being published - see +Operating System Source Code Secrets by Bill and Lynne Jolitz. +See comp.os.386bsd.*. +See +http://www.paranoia.com/~vax/boot.html for NetBSD +boot and partitioning info. +

+

a6 OpenBSD

OpenBSD, led by Theo de Raadt, split off from NetBSD. +It tries to emphasize on security. See +http://www.openbsd.org/. +

+

a6 HP Volume Expansion (SpeedStor variant)

+

+

a7 NeXTStep

Based on Mach 2.6 and features of Mach 3.0, is a true +object-oriented operating system and user environment. +See +http://www.next.com/. +

+

a8 Mac OS-X

Apple's OS-X ( +Darwin Intel) uses this type for its filesystem partition +(a UFS file system, in NeXT flavour, only differing from the *BSD formats +in the first 8 KB). See also type ab. +

+

a9 NetBSD

NetBSD is one of the children of *BSD (see above). +It runs on PCs and a variety of other hardware. +Since 19-Feb-98 NetBSD uses a9 instead of a5. +See +http://www.netbsd.org/. +It is freely obtainable - see +http://www.netbsd.org/Sites/net.html. +

+

aa Olivetti Fat 12 1.44MB Service Partition

Contains a bare DOS 6.22 and a utility to exchange types +06 and aa in the partition table. (loekw@worldonline.nl) +

+

ab Mac OS-X Boot partition

Apple's OS-X (Darwin Intel) uses this type for its boot partition. +The image (/usr/standalone/i386/boot) starts at sector 1. +See also type a8. +

+

ab GO! partition

Unused. Claimed by Stanislav Karchebny for his +GO! OS. +

+

ae ShagOS filesystem

+

af ShagOS swap partition

Unused. Claimed by Frank Barrus for his +ShagOS. +

+

b0 BootStar Dummy

The boot manager BootStar manages its own partition table, +with up to 15 primary partitions. It fills unused entries in the +MBR with BootStar Dummy values. +See +www.star-tools.com. +If you use this, don't use a disk manager, do not put LILO in the MBR +and do not use fdisk. +

+

b1 HP Volume Expansion (SpeedStor variant)

+

+

b3 HP Volume Expansion (SpeedStor variant)

+

+

b4 HP Volume Expansion (SpeedStor variant)

+

+

b6 HP Volume Expansion (SpeedStor variant)

+

+

b6 Corrupted Windows NT mirror set (master), FAT16 file system

+

b7 Corrupted Windows NT mirror set (master), NTFS file system

+

b7 BSDI BSD/386 filesystem

+

+

b8 BSDI BSD/386 swap partition

BSDI (Berkeley Software Design, Inc.) was founded by former CSRG +(UCB Computer Systems Research Group) members. +Their operating system, based on Net/2, was called BSD/386. +After the USL (Unix System Laboratories, Inc./Novell Corp.) vs. BSDI +lawsuit, new releases were based on BSD4.4-Lite. +Now they are announcing BSD/OS V2.0.1. This is an operating for PCs +(386 and up), boasting 3000 customers. (That was long ago. The current +partition id is 9f, see above.) +

+

bb Boot Wizard hidden

(PTS) BootWizard 4.0 and its new version Acronis OS Selector 5.0 +use this id (i) when hiding partitions with types other than +01, 04, 06, 07, 0b, +0c, 0e, and (ii) when creating a partition +without file system. +See +www.PhysTechSoft.com. The boot software was purchased +on 2001-01-05 by SWsoft. See +www.acronis.com. +

+

be Solaris 8 boot partition

+

+

bf New Solaris x86 partition

The old 0x82 id conflicted with Linux swap. New Solaris installations +will use the id 0xbf. (Larry Lee <lclee@west.sun.com>) +

+

c0 CTOS

+

+

c0 REAL/32 secure small partition

See d0 below. +

+

c0 NTFT Partition

According to disk.c in the Netware source. +

+

c0 DR-DOS/Novell DOS secured partition

DR-DOS 7.02+ / OpenDOS 7.01 / Novell DOS 7 secured partition. +

+

c1 DRDOS/secured (FAT-12)

+

+

c2 Unused

According to +Powerquest +IDs c2, c3, c8, c9, ca, +cd are reserved for DR-DOS 7+. +According to Matthias Paul c2, c3, cd +are no longer reserved for DR-DOS. +

+

c2 Hidden Linux

+

+

c3 Hidden Linux swap

Benedict Chong (bchong@blueskyinnovations.com) writes: +BlueSky Innovations LLC does a boot manager product +called Power Boot and we use, in addition, +0C2h and 0C3h for hidden Linux partitions (swap and ext2fs). +See also ID c2. +

+

c4 DRDOS/secured (FAT-16, < 32M)

+

+

c5 DRDOS/secured (extended)

This ID may also be used in obscure trickery: +on a shared MS-DOS / DR-DOS machine with DR-DOS 6.0-7.03 (so that +the DR_DOS does not understand type 0f and the MS-DOS +does not understand type c5) one may have two extended +partitions, where each operating system sees only one. +

+

c6 DRDOS/secured (FAT-16, >= 32M)

DR-DOS 6.0 and higher (NetWare PalmDOS 1.0, Novell DOS 7, OpenDOS 7.01, +DR-DOS 7.02+) will add 0xc0 to the partition type for +a LOGIN.EXE-secured partition (so that people cannot avoid +the password check by booting from an MS-DOS floppy). +Otherwise it seems that the types c1, c4, c5, +c6 and d1, d4, d5, d6 +are used precisely like 01, 04, 05, 06 +(but are accepted only when booting from disk). +

+

c6 Windows NT corrupted FAT16 volume/stripe set

NTFS will add 0xc0 to the partition type for disabled parts +of a Fault Tolerant set. Thus, one gets types c6, c7. +See also +Windows NT Boot Process and Hard Disk Constraints and +Switching from DR-DOS 6.0 to MS-DOS 5.0. +

+

c7 Windows NT corrupted NTFS volume/stripe set

+

+

c7 Syrinx boot

Primary partition only. +

+

c8 Reserved for DR-DOS 8.0+

+

c9 Reserved for DR-DOS 8.0+

+

ca Reserved for DR-DOS 8.0+

+

cb DR-DOS 7.04+ secured FAT32 (CHS)/

+

cc DR-DOS 7.04+ secured FAT32 (LBA)/

+

cd CTOS Memdump?

+

+

ce DR-DOS 7.04+ FAT16X (LBA)/

+

cf DR-DOS 7.04+ secured EXT DOS (LBA)/

+

d0 REAL/32 secure big partition

REAL/32 is a continuation of DR Multiuser DOS. +It supports FAT12, FAT16 and REAL/32 7.90 also supports FAT32. +Andrew Freeman (afreeman@imsltd.com) writes: +For partitions which have been marked as secure we use +0xC0 and 0xD0 as partition markers (C0 < 32mb, D0 >= 32mb). +REAL/32 is an advanced 32-bit multitasking & multi-user +MS-DOS & Windows compatible operating system. +Home page is +www.imsltd.com. +

+

d0 Multiuser DOS secured partition

This applies to the whole MDOS family range, Digital Research +DR Multiuser DOS and Novell DR Multiuser DOS, as well as to +Concurrent Controls Multiuser DOS, Datapaq Australasia System Manager 7, +and IMS Multiuser DOS. +

+

d1 Old Multiuser DOS secured FAT12

+

+

d4 Old Multiuser DOS secured FAT16 <32M

+

+

d5 Old Multiuser DOS secured extended partition

+

+

d6 Old Multiuser DOS secured FAT16 >=32M

+

d8 CP/M-86

+

+

da Non-FS Data

Added on request of John Hardin (johnh@aproposretail.com). +

+

db Digital Research CP/M, Concurrent CP/M, Concurrent DOS

+

+

db CTOS (Convergent Technologies OS -Unisys)

+

+

db KDG Telemetry SCPU boot

Mark Morgan Lloyd (markMLl.in@telemetry.co.uk) writes: +KDG Telemetry +uses type 0xdb to store a protected-mode binary image of the code +to be run on a 'x86-based SCPU (Supervisory CPU) module from the DT800 range. +

+

dd Hidden CTOS Memdump?

+

+

de Dell PowerEdge Server utilities (FAT fs)

+

+

df DG/UX virtual disk manager partition

Glenn Steen (glenn.steen@ap1.se) writes: +When I made an old Aviion 2000 triple-boot (DOS, DG/UX and Linux) +I saw that Linux fdisk reported the DG/UX virtual disk manager +partition as type 0xdf. +

+

df BootIt EMBRM

The boot manager BootIt manages its own partition table, +with up to 255 primary partitions. See +www.terabyteunlimited.com. +If you use this, don't use a disk manager, do not put LILO in the MBR +and do not use fdisk. Reference for the ID: BOOTIT.TXT. +

+

e0 Reserved by +STMicroelectronics for a filesystem called ST AVFS.

+

+

e1 DOS access or SpeedStor 12-bit FAT extended partition

Kevin Cummings reports in alt.os.linux: +it's a SSTOR partition on cylinders > 1023. +

+

e3 DOS R/O or SpeedStor

+

+

e4 SpeedStor 16-bit FAT extended partition < 1024 cyl.

+

+

e5 Tandy MSDOS with +logically sectored FAT

+

e6 Storage Dimensions SpeedStor

+

+

eb BeOS BFS

BeOS is an operating system that runs on Power PCs and on Intel PCs. +Version 5 +(the last version) is distributed freely to individuals. +The system was sold to Palm and is not developed any more. +OpenBeOS +tries to create an open source version. +

+

ec SkyOS SkyFS

+SkyOS +is an operating system written by Robert Szeleney. +Its filesystem SkyFS is based on OpenBeFS. +

+

ed Unused

Matthias Paul plans to use this for an OS called Sprytix. +

+

ee Indication that this legacy MBR is followed by an EFI header

+

+

ef Partition that contains an EFI file system

Bob Griswold (rogris@Exchange.Microsoft.com) writes: +MS plans on using EE and EF in the future for support of +non-legacy BIOS booting. +Mark Doran (mark.doran@intel.com) adds: these types are used to +support the Extensible Firmware Interface specification (EFI); go to +developer.intel.com +and search for EFI. +(For the types ee and ef, see Tables 16-6 and 16-7 of +the EFI specification, EFISpec_091.pdf.) +

+

f0 Linux/PA-RISC boot loader

Paul Bame (bame@debian.org) writes: the F0 partition will be +located in the first 2GB of a drive and used to store the +Linux/PA-RISC +boot loader and boot command line, optionally including a kernel and ramdisk. +

+

f1 Storage Dimensions SpeedStor

+

+

f2 DOS 3.3+ secondary partition

Matthias Paul writes: +"This ID was originally used by Sperry IT MS-DOS 3.xx for a +logically sectored variant of FAT. +When Sperry IT became part of Unisys, the operating system was called +Unisys MS-DOS 3.3. Digital Research's DOS Plus 2.1 (for OEM machines +such as the Amstrad/Schneider PC1512, the T.R.A.N. Jasmin Turbo (Speed 8M), +or the Acorn BBC Master 512 also supports this ID and logs it in, as +if this would be either a type 01h FAT12 or a type 04h FAT16 partition." +

+

f3 Reserved

+Powerquest +writes: Storage Dimensions SpeedStor. +

+

f4 SpeedStor large partition

+

+

f4 Prologue single-volume partition

+

+

f5 Prologue multi-volume partition

The type F4 partition contains one volume, and is not used anymore. +The type F5 partition contains 1 to 10 volumes (called MD0 to MD9). +It supports one or more systems (Prologue 3, 4, 5, Twin Server). +Each volume can have as file system the NGF file system or TwinFS file system. +NGF (old): volume size at most 512 MB, at most 895 files per directory, +at most 256 directories per volume. +TwinFS (new): volume size up to 4 GB. +No limit in number of files and directories. +See +Prologue. +

+

f6 Storage Dimensions SpeedStor

+

+

f7 Unused

Maybe Natalia Portillo plans to use this for O.S.G. EFAT +("Enhanced File Allocation Techniques"). +

+

f9 pCache

Ed Sawicki writes: "We propose using the F9 partition type as +a pCache partition, which is our name for an "ext2/ext3 persistent +cache partition". See +www.alcpress.com. +

+

fa Bochs

Rob Judd writes: MandrakeSoft's +Bochs x86 emulator +(similar to VMWare) uses fa as a partition identifier. +

+

fb VMware File System partition

+

+

fc VMware Swap partition

+VMware +offers virtual machines in which one can run Linux, Windows, FreeBSD. +These partition IDs announced by Dan Scales +(scales@vmware.com). +

+

fd Linux raid partition with autodetect using persistent superblock

See the +HOWTO +and the +kernel patches. +Earlier, 86 was used instead of fd. +

+

+Powerquest +writes: Reserved for FreeDOS +( +www.freedos.org), +but it seems FreeDOS never used this ID. +

+

fe SpeedStor > 1024 cyl.

+

fe LANstep

+

+

fe IBM PS/2 IML (Initial Microcode Load) partition, +located at the end of the disk.

+

+

fe Windows NT Disk Administrator hidden partition

Mark Morgan Lloyd (markMLl.in@telemetry.co.uk) writes: +Windows NT Disk Administrator marks hidden partitions (i.e. present but +not to be accessed) as type 0xfe. A primary partition of this type is also +used by IBM to hold an image of the "Reference Diskettes" on many of their +machines, particularly newer PS/2 systems (at a rough guess, anything built +after about 1994). This clash can cause major confusion and grief +if running NT on IBM kit. +When this Reference Partition is activated, it changes its type into 1 +(FAT12) and hides all other partitions by adding 0x10 to the type. +

+

fe Linux Logical Volume Manager partition (old)

This has been in use since the early LVM days back in 1997, +and has now (Sept. 1999) been renamed 0x8e. +

+

ff Xenix Bad Block Table

+

+

+

+

+Next +Previous +Contents + + diff --git a/specs/partitions/partition_types-2.html b/specs/partitions/partition_types-2.html new file mode 100644 index 0000000..5688e5d --- /dev/null +++ b/specs/partitions/partition_types-2.html @@ -0,0 +1,644 @@ + + + + + Partition types: Properties of partition tables. + + + + +Next +Previous +Contents +
+

2. Properties of partition tables.

+ +

+

2.1 Why partitions? +

+ +

+

The partition table of a disk cuts it into 'logical disks'. +There are several reasons for wanting to do this. +DOS does not support filesystems larger than 2 GB, so +partitioning is required to break this '2 GB barrier'. +Different partitions may carry different operating systems +or different filesystems (FAT, HPFS, NTFS, ext2, ...) to be used by one +operating system. Sometimes small partitions are used for special purposes +(OS/2 Boot Manager uses a small partition for itself, various laptops +have a 'hibernation' partition where the state of the system is stored +when it goes asleep). Some 'reliable' systems have backup partitions. +For backup purposes, say to tape, it is often convenient to have +partitions of a size such that the entire partition can be written +to a single tape. +

It is a good idea to keep your own things (say under /home) +and privately installed packages (say under /usr/local) +separate from the software installed from a distribution. +In case these are on a different partition, it is easier +to do a complete reinstall (or switch to a different distribution) +without losing your own stuff. +

For well-designed systems it is often possible to have all basic +system software on a read-only partition, thus diminishing the probability +of corruption and saving backup time. +There is also a security aspect; for example on a Unix system one +might mount all filesystems other than the root filesystem 'nosuid,nodev', +and have /tmp, /home, /var not on the root filesystem, to minimize the +possibility that some suid program is tricked into overwriting a +vital system file via a hard link to it. +

Finally there is the old BIOS problem that can make it impossible to boot +a system that lives past cylinder 1024. This may mean that one has to +have a partition that ends before the 1024 cylinder limit where the +stuff needed at boot time is stored. +

Some reasons why you want to avoid Disk Managers are given on +The Invircible Anti-virus Manual, Appendix C. +

+

2.2 What does a partition table look like? +

+ +

+

One may have an arbitrary number of partitions on a disk. +However, the Master Boot Record (MBR, sector 0 of the disk) +only holds descriptors for 4 partitions, called the primary +partitions. Usually the BIOS can boot only from a primary partition. +(Of course it can boot a boot loader that itself is able to access +nonprimary partitions or other disks.) +The descriptors for the remaining partitions, called logical partitions, +are scattered along the disk in a linked list of partition table sectors, +starting with the MBR. +

Each partition table sector contains 4 partition descriptors. +A partition descriptor may be of type 05 (DOS extended partition), +0f (W95 extended partition), 85 (Linux extended partition), +or c5 (DRDOS/secured extended partition), +in which case it points to another partition table sector. +In this way, we obtain a quaternary tree of partitions. +Linux accepts 85 as a synonym for 05 - this is useful if one +wants to have extended partitions past the 1024 cylinder limit +(to prevent DOS fdisk from crashing or hanging). +Windows 95 uses 0f for LBA mapped extended partitions. +Thus, an extended partition is not a partition containing data, +but is a box containing other partitions. +Nevertheless, the partition table sector that starts an extended partition +has enough room left to contain a boot loader like LILO, so that it is +possible to boot an extended partition. +

Most operating systems severely restrict the accepted trees. +Usually branching is not allowed, and one gets a linear chain of +partition table sectors. +Linux will accept several extended primary partitions. +

+

+

2.3 Partition descriptors +

+ +

+

A partition table entry is 16 bytes long and contains 6 items +(not listed in order). +1. A byte that is 0x80 or 0 denoting 'bootable' or not. +The standard DOS MBR will not boot a partition unless it is the unique +bootable primary partition. For nonprimary partitions this byte is +unused. +2. A byte that gives the type. +3. A 4-byte starting sector number. +4. A 4-byte length (in sectors). +5. A 3-byte starting sector given in C/H/S (cylinder/head/sector) format. +6. A 3-byte final sector given in C/H/S format. +Linux only uses items 2-4, and hence is not interested in the 'geometry' +of the disk, and can use disks with up to 2^32 sectors (4 TB). +DOS uses 5-6 instead of 3-4, and this leads to the well-known problems +with geometry, with the 1024 cylinder limit, the 500 MB limit, the 8 GB +limit. For some details, see the +large disk HOWTO. +

For an extended partition, only the first sector is important - +it contains the descriptors for its logical partitions. +There are various conventions about how the descriptor of an +extended partition (different from the outer one) should look like. +There is the paradigm of 'nested boxes', where each extended partition +covers a disk area containing all the logical partitions inside. +There is also the paradigm of 'chained boxes', where each extended +partition (except possibly the outer one) just contains the next +logical partition. +I don't know which systems follow which paradigms. +(David A. Burton <dburton@burtonsys.com> reports +that System Commander uses the nested style.) +However, for the outer (primary) extended partition it is common +to contain all logical partitions inside (i.e., have a start and length +field that describes a piece of the disk that contains all logical +partitions). +Of course the 'chained boxes' paradigm is more flexible since it +allows logical partitions with a primary partition in between. +

+

+

2.4 Partition hiding +

+ +

+

The OS/2 Boot Manager does not want you to have more than one +primary DOS partition (MS-DOS itself does not mind), and will +change the type from 01, 04, 06, 07 +to 11, 14, 16, 17. +

Also other programs or systems use this 'partition hiding'. +For example, +System Commander will OR the type with 0x10, +changing the Linux 83 into the Amoeba 93. +

+

2.5 CHS vs LBA +

+ +

Some partition IDs imply a particular method of disk access. +In particular, IDs 0c, 0e, 0f +(the LBA versions of 0b, 06, 05) +go with partition table entries that have C/H/S = 1023/255/63 +and expect access via the extended INT-13 functions (AH=4x) +of the BIOS. +

+

2.6 Logically sectored FAT +

+ +

Some systems use a filesystem that is fully compatible with +a standard FAT12 or FAT16 partition, except for using a +sector size larger than the usual 512 bytes, up to 8192 bytes. +This is what is meant by "logically sectored FAT" in the above. +

Logically sectored FATs have been a way to circumvent the dreaded 32 MB +partition size limit before the introduction of DOS 3.31. Since the +count of sectors was restricted to 16-bit on FAT16 (type 04h) the only +way to grow the partition above the 32 MB limit in a reasonably compatible +fashion was to increase the sector size instead. Physical sectors at +ROM BIOS INT 13h level are always 512 bytes in size, but other devices +may require support for other sector sizes in the operating system. +Hence, when DOS logs in drives during bootstrap it will record the +sector size values indicated in each partition it finds and if it +is larger than the previously recorded value, it will slide up the +maximum supported sector size to the found value. Very old DOS versions +seem to have started with an initial value of 128 (showing some +CP/M heritance here), but recent DOS versions use an initial value +of 512 bytes. Once DOS has logged in all drives (including those +not represented on INT 13h level, for example, SCSI disk, RAM disk +or such), it will set up its internal buffering logic to use the +maximum sector size found. This mechanism is present in all +DOS versions (although it was partially broken in DOS 5.0 - 6.22). +

(Matthias Paul) +

+

+

2.7 What does FDISK /MBR do? +

+ +

+

People often recommend the undocumented DOS command FDISK /MBR +to solve problems with the MBR. This command however does not +rewrite the entire MBR - it just rewrites the boot code, the first +446 bytes of the MBR, but leaves the 64-byte partition information +alone. Thus, it won't help when the partition table has problems. +Moreover, it can be dangerous to restore the boot code to its +original state: +if the cause of the problems was a boot sector virus, then +vital information may have been stored elsewhere by the virus, +and killing the virus may mean killing access to this information. +(For example, the stoned.empire.monkey virus encrypts the original +MBR to sector 0/0/3.) +However, people who want to uninstall LILO, and do not know that +LILO has a -u option, can use FDISK /MBR for this purpose. +

In a Linux environment, one can wipe all of the MBR with a command +like "dd if=/dev/zero of=/dev/hda count=1 bs=512". +If only the boot code must be removed, but not the partition table, +then "dd if=/dev/zero of=/dev/hda count=1 bs=446" will do. +Be very careful with such commands. Usually one regrets them later. +

+

2.8 Structure of the MBR - OS additions +

+ +

As we saw, the structure of the MBR (Master Boot Record, sector 0) +is as follows: +First 446 bytes boot loader code, then 64 bytes partition table +(starting at offset 0x1be = 446), finally 2 bytes signature 0xaa55. +

Just before the partition table some operating systems save some +interesting stuff. For example, DRDOS stores a password starting +at offset 0x1b6. +

Windows NT stores a 4-byte "disk signature" or "volume ID" +starting at offset 0x1b8. It is used to map drive letters to disks: +in the HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices registry item +the drive letter is coupled with this disk signature. +It is used as a disk label to map disk info to disks +in the HKEY_LOCAL_MACHINE\SYSTEM\DISK registry item. +This signature is generated by the Disk Administrator when it +initializes the disk, unless there already was a nonzero value there. +

Grub had a 4-byte stage2 start address at 0x1b8, and a 2-byte +version at 0x1bc, but recent versions preserve 0x1b8-0x1bd. +Also LILO v20 and later preserves this area. +

Some operating systems are reported to have 8 instead of 4 +partition descriptors in the MBR. Cf. AST DOS under 14 +and NEC DOS under 24 above. +

+

2.9 The Advanced Active Partition of PTS +

+ +

As mentioned above, the DOS MBR boot code will boot the +(unique) primary partition that has been marked active. +Usually, in a multi-boot situation, the boot manager toggles +the active bit of the partition that is to be booted. +PTS chose a different solution. +

Matthias Paul writes: +"So far the only DOS being able to boot out of a logical drive +in an extended partition is PTS-DOS by use of so called +"Advanced Active Partition" entries in the MBR. In order to +remain as compatible as possible with existing DOS standards, +this works a little bit different and requires a special 5th +partition entry in front of the other four entries in the MBR +and corresponding AAP-aware MBR bootstrap code. If the MBR +contains a special AAP signature and this special entry exists +and is flagged bootable, the MBR will use this instead of one +of the other four entries. The entry may either point to the +bootsector of a logical drive or to a 512 bytes long file +(with system-attribute, so it won't be moved around during +disk defragmentation) somewhere inside the filesystem, which +makes up a boot sector (same "IBM" signature, same load address, +same register interface). In contrast to the usual MBR code, +this MBR code interprets the boot flag byte as physical drive +unit (80h..FEh), instead of using it only as a active flag +(80h or 00h in older DOS issues or bit 7 set or cleared in +newer DOS issues). This way, the AAP MBR could even load a +boot sector from other than the first harddisk." +

+

2.10 Naming +

+ +

+

DOS uses drive letters A: and B: for floppy disk drives, and +assigns drive letters C: ... Z: in the order: first all primary +DOS partitions on the first disk, then all primary DOS partitions +on the second disk, ..., then all logical DOS partitions on first +disk, etc. DOS will stop investigating logical partitions in a given +extended partition as soon as a non-DOS partition is encountered. +(DOS recognizes partition types 1, 4, 6 and 5 for extended.) +

Systems like Windows 95, Windows 98, Windows NT, Windows 2000 and OS/2 +follow a similar convention, but recognize different partition types. +Thus, a drive can have a different drive letter for each of these +operating systems. For details, see the Microsoft KnowledgeBase, e.g. +Drive letters in Windows NT, +Drive letters in Windows 2000 for unsupported partition types. +

+

2.11 Limits +

+ +

The partition table describes the location of partitions both +in 1-dimensional ('LBA') and in 3-dimensional (CHS) form. +The former is easy enough, but for the latter one needs to +know the disk geometry. Note that these days this geometry +is entirely fake, and different systems use different faked +geometries for the same disk, giving lots of problems. +(For example, a modern disk may have 2 or 4 heads, but will +probably report 15 or 16 heads to the BIOS, which in turn may +report 255 heads to DOS or Windows.) +

+

+

+

ATA Specification (for IDE disks) - the 137 GB limit

At most 65536 cylinders (numbered 0-65535), 16 heads (numbered 0-15), +255 sectors/track (numbered 1-255), for a maximum total capacity of +267386880 sectors (of 512 bytes each), that is, 136902082560 bytes (137 GB). +

+

BIOS Int 13 - the 8.4 GB limit

At most 1024 cylinders (numbered 0-1023), 256 heads (numbered 0-255), +63 sectors/track (numbered 1-63) for a maximum total capacity of +8455716864 bytes (8.4 GB). This is a serious limitation today. +It means that DOS cannot use present day large disks. +

+

The DOS 528 MB limit

If the same values for c,h,s are used for the BIOS Int 13 call and +for the IDE disk I/O, then both limitations combine, and one can +use at most 1024 cylinders, 16 heads, 63 sectors/track, for a +maximum total capacity of 528482304 bytes (528MB), the infamous +504 MB limit (if one takes M=2^20). +This was already a problem many years ago, and all kinds of software, +firmware and hardware solutions were invented. On the software side, +there are Disk Managers, that circumvent the BIOS and go directly to +the hardware. On the firmware side there are translating BIOSes, +that use one geometry when talking to the disk, and another one +when talking to the user program. (At best, this again allows access +to 8.4 GB.) On the hardware side, there is LBA disk access, +that no longer uses (c,h,s). +

+

The 2.1 GB limit

Some older BIOSes only allocate 12 bits for the field in CMOS RAM that +gives the number of cylinders. Consequently, this number can be at most +4095, and only 4095*16*63*512=2113413120 bytes are accessible. +See +over2gb.htm. +

+

The 3.2 GB limit

There was a bug in the Phoenix 4.03 and 4.04 BIOS firmware that would +cause the system to lock up in the CMOS setup for drives with a capacity +over 3277 MB. See +over3gb.htm. +

+

The 4.2 GB limit

Simple BIOS translation (ECHS=Extended CHS, sometimes called 'Large +disk support' or just 'Large') +works by repeatedly doubling the number of heads and halving the number +of cylinders shown to DOS, until the number of cylinders is at most 1024. +Now DOS and Windows 95 cannot handle 256 heads or more, +and in the common case that the disk reports 16 heads, this means that +this simple mechanism only works up to 8192*16*63*512=4227858432 bytes +(with a fake geometry with 1024 cylinders, 128 heads, 63 sectors/track). +Note that ECHS does not change the number of sectors per track, so if +that is not 63, the limit will be lower. +See +over4gb.htm. +

+

The 7.9 GB limit

Slightly smarter BIOSes avoid the previous problem by first adjusting the +number of heads to 15 ('revised ECHS'), so that a fake geometry with +240 heads can be obtained, good for 1024*240*63*512=7927234560 bytes. +

+

The 8.4 GB limit

Finally, if the BIOS does all it can to make this translation a success, +and uses 255 heads and 63 sectors/track ('assisted LBA' or just 'LBA') +it may reach 1024*255*63*512=8422686720 bytes, slightly less than the +earlier 8.4 GB limit because the geometries with 256 heads must be avoided. +(This translation will use for the number of heads the first value H +in the sequence 16, 32, 64, 128, 255 for which the total disk capacity +fits in 1024*H*63*512, and then computes the number of cylinders C as +total capacity divided by (H*63*512).) +

+

The 33.8 GB limit

Large disks report 16 heads, 63 sectors/track and 16383 cylinders. +Many BIOSes compute an actual number of cylinders by dividing +the total capacity by 16*63. For disks larger than 33.8 GB this +leads to a number of cylinders larger than 65535. Now the BIOS +crashes or hangs. The solution is to upgrade the BIOS. If that is +impossible, it sometimes helps to take the disk out of the BIOS, +but that won't work if one has to boot from the disk, and may also +fail because the BIOS already hangs during initial probing. +Usually one can use a jumper to make the disk appear smaller. +Also many operating systems have problems - only the most recent +versions work with these disks. +

+

The 137 GB limit

As already noted, the old ATA specification does not allow access +to all of a disk that is larger than 137 GB. Indeed, it uses only +28 bits to specify a sector number. However, ATA-6 defines an extension +with 48-bit sector number. The first disks needing the extension were +Maxtor 160 GB disks, that came to market in Fall 2001. +

+

For another discussion of this topic, see +Breaking the Barriers, and, with more details, +IDE Hard Drive Capacity Barriers. +

Hard drives over 8.4 GB are supposed to report their geometry as 16383/16/63. +This in effect means that the 'geometry' is obsolete, and the total disk +size can no longer be computed from the geometry. +

+

2.12 Details for various operating systems +

+ +

+

Early MSDOS filled the partition table starting at the end. +In particular, in the case of only one partition, the descriptor +was stored in the fourth primary slot. These days DOS FDISK +starts at the beginning, but other systems, like Unixware, still +start at the end. +Also Iomega writes the single partition of a ZIP disk +in the last entry (so that it has to be mounted as /dev/sda4 or +/dev/hdc4 or so). +

MSDOS 6.22 FDISK creates the four entries in the partition table sector +that starts an extended partition as 1. a data partition (or empty), +2. the next extended partition, 3. and 4. empty. +(But old versions of MS-DOS start at the end, and first fill entry 4.) +If the first logical partition (that is not the last one) is removed, +only the link in position 2 remains. +An extended partition table sector can describe only a single +data partition (the first one encountered). When reading a table, +FDISK accepts the entries in any order and position, but it will +write the sector normalized as described. +

DRDOS on the other hand expects zero to four entries in an extended +partition table sector. Data partitions, +possibly followed by the link to the next extended partition. +Thus, this link is always the last significant entry, and will +be the first entry if there is no data partition (because +it has been deleted). +

Many systems are willing to accept more than two nonempty parts +in an extended partition, but will not create such themselves. +

It is rumoured that the outer extended partition should be the 4th +in the MBR, but I don't know any systems that have this restriction. +DRDOS FDISK always puts the extended partition in the fourth entry +no matter how many other entries you may have. +

MSDOS fdisk shows 4 primary partitions, and of the logical partitions +only those that have a DOS type (1, 4 or 6). It will list the type of +a logical partition as 'Unknown' if the partition is not formatted. +

It is rumoured that DRDOS ignores the high-order bit of the ID +(and that is the reason for the additional Linux IDs 41, 42, 43), +but I don't know whether that is true (and for which versions of DRDOS). +It is also rumoured that DRDOS will write 1 sector past the end +of a partition - I have never seen this either. Confirmation? +It is however true, that DRDOS fdisk only looks at the last 4 bits +when printing a type, so that types 11, 21, etc are printed as DOS 2.0, +but such types are not acceptable for DRDOS itself. +

The OS/2 Warp fdisk is very instable, and hangs or crashes with +general protection fault as soon as the partition table is somewhat +unusual, cf. +Cannot set an installable partition with FDISK. +

The Windows NT Disk Administrator will corrupt your disk +when it writes a signature on a disk with two or more +logical partitions. See +Disk Administrator Corrupts Partitions. +

The use of Win95/Win98 FDISK in a mixed system is dangerous. +It will delete a non-FAT logical partition when you had actually +told it to delete a FAT partition somewhere farther down the chain +of logical partitions. See +Cannot View NTFS Logical Drive After Using FDISK. +

The system partition in Windows NT 4 must be contained in the first +7.8 GB of the disk (or less, in case the BIOS geometry does not have +255 heads and 63 sectors/track; the actual restriction is that all of it +must be accessible using BIOS Int 13). +It must not be larger than 4 GB because Windows NT 4 first installs +into a FAT16 partition and then converts it into NTFS during +the second phase of the installation. +It must start before the 4 GB mark (bug fixed in Service Pack 5). +See +Windows NT 4.0 Supports Maximum of 7.8-GB System Partition +and +Windows NT Partitioning Rules During Setup +and +Boot Partition Created During Setup Limited to 4 Gigabytes +and +Windows NT Does Not Boot to a Partition That Starts More Than 4 GB into Disk. +

Windows NT and Windows 2000 use for SCSI disks whatever the BIOS says +(usually C/H/S=C/255/63) for the boot drive, and C/64/32 +for all other SCSI drives. See +How Windows NT Handles Drive Translation. +

Windows 2000 seems to require that the partition order agrees +with the disk order. +

The OS/2 fdisk writes some strange length in the descriptor of the +last extended partition. This is probably a bug. +OS/2 fdisk fails to update the length of the (outer) extended partition +when a primary partition is created in the free space (space not used +by a logical partition) at the end of this extended partition. +This can lead to overlapping partitions. +

OS/2 FDISK does not know about type f, but accepts DOS Extended Partitions +extending beyond cylinder 1023. When some other partition handler, +like Partition Magic 4.0, changes the type of a large extended +partition from 05 to 0f, OS/2 loses access. +

OS/2 Boot Manager keeps a private copy of the partition table data. +This leads to problems when changing the partition table +with 3rd party tools. +

+ +Windows 2000 tries to destroy OS/2 Boot Manager. Upon boot it ignores +the 0a partition ID, and sees something resembling a FAT boot sector +describing 2 FAT copies. When FASTFAT.SYS marks this partition as clean +in the first reserved FAT entry, the mirror (2nd) FAT sector is also updated. +However, there is no mirror FAT, and FASTFAT.SYS writes into the middle of +the OS/2 Boot Manager code. This aggression was built into FASTFAT.SYS +at a fairly late stage, and prerelease versions work without problems. +See also +kb/q265003. +Update both \WINNT\SYSTEM\DRIVERS\FASTFAT.SYS and +\WINNT\SYSTEM\DLLCACHE\FASTFAT.SYS . +

+ +Then there is the problem of what to write in +(c,h,s) if the numbers +do not fit. The main strategies seem to be +

1. Mark (c,h,s) as invalid by writing +some fixed value. +

1a. Write (1023,255,63) for any nonrepresentable CHS. +

1b. Write (1022,254,63) for any nonrepresentable CHS. +

1c. Write (1023,0,1) for the begin CHS of a partition that +starts at or past cylinder 1024, and write (1023,255,63) for the end. +

2. Leave h, s but do something to c. +Of course, these fail if h or s does not fit. +

2a. Truncate c to 1023, writing +(1023, #heads-1, #sectors). +

2b. Truncate c to 1022, writing +(1022, #heads-1, #sectors). +

2c. Reduce c mod 1024, writing only its last 10 bits. +

Solaris 8 follows 1b or 2b. +Andreas Jellinghaus reports that Partition Magic follows 1c +and detects a problem if start CHS is set to (1023,255,63). +Jeff Merkey reports that Novell Netware follows 2b. +He writes: If you do not use their methods on NetWare +partitions, NetWare will not recognize the partition entries correctly, +and will attempt to reinitialize the entire partition table on a system +if they are wrong (Ouch!). +Some versions of Linux fdisk used 2a or 2c, and this confuses OS/2 fdisk - cf. +Linux, OS/2 and >1024 Cylinder HDDs. +David A. Burton <dburton@burtonsys.com> reports +that System Commander Deluxe (from +V Communications) uses +

1c. Mark (c,h,s) as invalid by writing +c=1022. +(Maybe this is really 2b?) +

+

+

2.13 Partition Magic +

+ +

A very convenient tool for manipulating partitions is Partition Magic, +a commercial program from PowerQuest. Below a description of some of +its error numbers. (The URL that gave this information no longer exists.) +This is of interest also for those who do not have this program: it indicates +what conditions the PowerQuest people think a partition table should satisfy. +

(Not all of these conditions are complied with by DRDOS or OS/2 or Linux +or Windows NT on Alpha, so a partition manipulator should accept a much +wider range of partition tables, but such a program might try to follow +these rules when creating partitions.) +

+

+

+

100 - A forked extended partition

The MBR or some EPBR contains two extended partitions. +(PowerQuest uses the acronym EPBR for a link in the chain of +extended partition table sectors.) +(Linux comment: there are three partition types indicating an +extended partition, namely 0x5, 0xf, 0x85. DOS only recognizes the first. +Recent Windows only recognizes the first two. Linux will accept +two or more extended partitions in the MBR, and often it is useful +to have a 0x5 chain for use by DOS (where this chain +stays below the 1024 cylinder boundary) and a 0x85 chain for use by Linux. +Nothing is wrong with having both 0x85 and one of 0x5, 0xf in the MBR. +However, it is bad to have both 0x5 and 0xf. This is sometimes seen when +people use some fdisk-type program that does not yet know about 0xf on a +disk that already contains such an extended partition.) +

+

104 - Partition contains no sectors

The LBA Number of sectors value in the partition table is 0. +

+

105 - Partition does not start on cylinder boundary

The Head value of CHS begin is not 0 or 1. +PartitionMagic expects all FAT, HPFS and NTFS partitions to start +and end on cylinder boundaries. +(Comment: Windows NT on Alpha does not comply with this rule, and +can create partitions starting on arbitrary sectors. There is no +known operating system that requires this restriction. However, +there exists software that tries to guess the disk geometry by +looking at the CHS start and end values in a partition table. +Note that with large disks CHS values are entirely meaningless.) +

+

106 - Partition does not start with sector 1

The Sector value of CHS begin is not 1. (Same comment.) +

+

107 - Partition begins beyond the end of the disk

The Cylinder value of CHS begin is larger than the number +of cylinders that the BIOS reports. +(Comment: Usually this means that programs or operating systems +that use the BIOS cannot use this partition. It may help to +change the BIOS translation. For Linux it does not matter, +except that the /boot partition containing LILO stuff +should be accessible.) +

+

108 - Partition does not end on cylinder boundary

The Head value of CHS end is not one less than the number of +heads that the BIOS reports, or the Sector value of CHS end +is not equal to the number of sectors per track that the BIOS reports. +(See above under 105.) +

+

109 - Partition ends after end of disk

The Cylinder value of CHS end is larger than the number +of cylinders that the BIOS reports. +

+

110 - Partition has different CHS and LBA lengths

+

+

111 - Logical partition starts outside extended

(Comment: the model here is that the extended partition is one +big box, taking a consecutive piece of disk area, containing +the logical partitions. Linux allows the logical partitions +to be anywhere on the disk, also with primary partitions in between.) +

+

112 - Logical partition ends outside extended

+

+

113 - Partitions overlap

A partition ends past the start of another. If the filesystems +don't actually overlap, which they rarely do, then this can be +fixed by truncating the overlapping partition. +(Sometimes overlapping partitions are created by OS/2 fdisk: +if there is still room in an extended partition it allows the creation +of a primary partition that overlaps the end of the extended partition. +Now if someone afterwards creates a logical partition inside the +extended partition, data loss might occur.) +

+

114 - Logical partition does not start one head away from EPBR

If the EPBR is found at sector N, and there are 63 sectors per track, +then Partition Magic expects the logical partition to start at sector +N+63. +

+

115 - Logical partition does not end where Partition Magic expects

(Comment: Partition Magic expects the extended partition to be +a big box containing a chain of pairwise disjoint boxes. +Here each logical partition except for the first one has the +same ending sector as the surrounding box. +Another model one finds is a big box containing a smaller +box, containing a smaller box ... In that model all EPBR extended +partition entries will show the same end sector. +In reality the end sector of an EPBR does not play a role anywhere.) +

+

116 - Partition has different CHS and LBA begin

+

+

120 - Logical partitions not in ascending order

PowerQuest states: DOS, OS/2, Windows 95 and Windows NT require +that logical partitions occur in the chain in the on-disk order. +(Comment: Linux does not require this. However, reordering the +links in the chain is trivial (for example with sfdisk). Note +that disk names will be different after reordering.) +

+

+

+

2.14 Acknowledgements +

+ +

A lot of useful information was supplied by various people: +Thomas Wolfram (thomas@aeon.in-berlin.de) - the author of os-bs, +Peter Gutmann (pgut01@cs.auckland.ac.nz) - the author of SFS, +Cody Batt (codyb@powerquest.com), +Christian Carey (ccarey@CapAccess.ORG), +Dan Fandrich (dan@fch.wimsey.bc.ca), +David Faulks (david@santana.ca), +Kai Henningsen (kai@khms.westfalen.de), +Dan Hildebrand (danh@qnx.com), +Todd Larason (jtl@molehill.org), +Mark Morgan Lloyd (markMLl.in@telemetry.co.uk). +Marek Michalkiewicz (marekm@i17linuxb.ists.pwr.wroc.pl), +David C. Niemi (niemidc@clark.net), +Matthias Paul (Matthias.Paul@post.rwth-aachen.de), +Loek Weerd (loekw@worldonline.nl), +S. Widlake (s.widlake@rl.ac.uk). +

+Next +Previous +Contents + + diff --git a/specs/partitions/partition_types.html b/specs/partitions/partition_types.html new file mode 100644 index 0000000..cb20a5e --- /dev/null +++ b/specs/partitions/partition_types.html @@ -0,0 +1,45 @@ + + + + + Partition types + + + + + +Next +Previous +Contents +
+

Partition types

+ +

Andries Brouwer, aeb@cwi.nl

2004-12-12 +

+

1. List of partition identifiers for PCs

+ +

+

2. Properties of partition tables.

+ + +
+Next +Previous +Contents + + -- 2.30.2