srs5694 | 91544e1 | 2010-01-28 21:10:36 -0500 | [diff] [blame] | 1 | GPT fdisk (aka gdisk)
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| 2 |
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| 3 | by Roderick W. Smith, rodsmith@rodsbooks.com
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| 4 |
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| 5 | ******************************** IMPORTANT ********************************
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| 6 | Most versions of Windows cannot boot from a GPT disk, and most varieties
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| 7 | prior to Vista cannot read GPT disks. GPT fdisk is a partition editor for
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| 8 | GPT disks, and it will *AUTOMATICALLY CONVERT* MBR disks to GPT form.
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| 9 | Therefore, you should **NOT** use GPT fdisk on a Windows system unless you
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| 10 | fully understand what you're doing! If you accidentally use GPT fdisk on
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| 11 | your boot disk, or perhaps even on a data disk, you may find recovery to be
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| 12 | very difficult!
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| 13 | ***************************************************************************
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| 14 |
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| 15 | Read the main README file for general information on the program, and read
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| 16 | the gdisk.html document (the Linux man page converted to HTML format) for
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| 17 | detailed use information. My GPT fdisk Web page,
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| 18 | http://www.rodsbooks.com/gdisk/, provides a more tutorial introduction to
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srs5694 | 55d9261 | 2010-03-07 22:16:07 -0500 | [diff] [blame] | 19 | the software. I originally wrote GPT fdisk on Linux, and some Linux- and
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| 20 | Unix-centric language remains in the documentation.
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srs5694 | 91544e1 | 2010-01-28 21:10:36 -0500 | [diff] [blame] | 21 |
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| 22 | Windows Use Notes
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| 23 | -----------------
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| 24 |
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| 25 | The Windows version of GPT fdisk was added with version 0.6.2 of the
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| 26 | package. The Windows binary package includes the gdisk.exe interactive
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| 27 | text-mode program file but no equivalent to the sgdisk program that's
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| 28 | available with Linux, FreeBSD, and OS X builds. In theory, an sgdisk.exe
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| 29 | for Windows could be built if the popt library were installed. I've not
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| 30 | attempted to do this myself, though. If you care to try, check
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| 31 | http://gnuwin32.sourceforge.net/packages/popt.htm for information on popt
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| 32 | for Windows.
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| 33 |
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| 34 | To install the program, copy the gdisk.exe program file to any directory on
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| 35 | your path, such as C:\Windows. Alternatively, you can change to the
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| 36 | program's directory or type its complete path whenever you use it.
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| 37 |
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| 38 | To use the program, first launch a Command Prompt as the Administrator. To
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| 39 | do this, locate the Command Prompt program icon, right-click it, and select
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| 40 | "Run as Administrator." If you use a non-Administrator Command Prompt, you
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| 41 | won't be able to edit hard disk partition tables, although you will be able
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| 42 | to edit raw disk image files.
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| 43 |
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| 44 | The program requires a hard disk identifier as an option. You can specify
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| 45 | this in either of two forms. The first way is as a number followed by a
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| 46 | colon, as in:
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| 47 |
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| 48 | gdisk 0:
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| 49 |
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| 50 | Disks are numbered starting from 0, so the preceding command launches gdisk
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| 51 | on the first disk. The second way to specify a disk device is via a
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| 52 | harder-to-remember name:
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| 53 |
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| 54 | gdisk \\.\physicaldrive0
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| 55 |
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| 56 | This command is equivalent to the earlier one -- it edits the partition
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| 57 | table on the first physical disk. Change the number at the end of the
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| 58 | device name to change the disk edited.
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| 59 |
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| 60 | If you pass the "-l" option in addition to the disk identifier, the program
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| 61 | displays the current partition table information and then exits. This use
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| 62 | entails no risk to MBR disks, since the program never writes data back to
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| 63 | the disk when used in this way.
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| 64 |
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| 65 | As noted above, editing the first disk with GPT fdisk is usually a Bad
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| 66 | Idea. An exception would be if your system uses an Extensible Firmware
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| 67 | Interface (EFI) and already boots from a GPT disk. It's safer to edit
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| 68 | non-boot disks, which usually have numbers of 1 and above, but only if you
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| 69 | run a version of Windows with GPT support. For more information on Windows'
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| 70 | support of GPT, see Microsoft's Web page on the topic:
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| 71 |
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| 72 | http://www.microsoft.com/whdc/device/storage/GPT_FAQ.mspx
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| 73 |
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srs5694 | 6699b01 | 2010-02-04 00:55:30 -0500 | [diff] [blame] | 74 | The GUIDs generated by the program to uniquely identify disks and
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| 75 | partitions aren't "proper" GUIDs; they're purely random numbers. In
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| 76 | practice, this has caused me no problems; however, it's conceivable that
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| 77 | some disk utility will complain. The Unix versions of GPT fdisk generate
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| 78 | proper GUIDs, as of version 0.6.3. Note that this limitation applies ONLY
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| 79 | to the unique GUIDs for disks and partitions, not to the GUIDs used to
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| 80 | identify partition type codes; those are standardized and are handled
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| 81 | correctly by all versions of GPT fdisk.
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| 82 |
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srs5694 | 91544e1 | 2010-01-28 21:10:36 -0500 | [diff] [blame] | 83 | Source Code and Compilation Issues
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| 84 | ----------------------------------
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| 85 |
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srs5694 | 55d9261 | 2010-03-07 22:16:07 -0500 | [diff] [blame] | 86 | I have successfully compiled GPT fdisk using two different Windows
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| 87 | compilers:
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srs5694 | 91544e1 | 2010-01-28 21:10:36 -0500 | [diff] [blame] | 88 |
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srs5694 | 55d9261 | 2010-03-07 22:16:07 -0500 | [diff] [blame] | 89 | - MinGW (http://www.mingw.org), and in particular its Linux-hosted
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| 90 | cross-compiler -- Under Fedora Linux, the Makefile.mingw file enables
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| 91 | compilation of the software via MinGW. (Type "make -f Makefile.mingw" to
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| 92 | compile the software.) If you try to compile using another compiler or
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| 93 | even using MinGW under Windows or another Linux variety, you may need to
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| 94 | adjust the Makefile.mingw options.
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srs5694 | 91544e1 | 2010-01-28 21:10:36 -0500 | [diff] [blame] | 95 |
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srs5694 | 55d9261 | 2010-03-07 22:16:07 -0500 | [diff] [blame] | 96 | - Microsoft Visual C++ 2008 Express
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| 97 | (http://www.microsoft.com/express/Windows/) -- This compiler requires a
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| 98 | third-party stdint.h file (I used the one from
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| 99 | http://msinttypes.googlecode.com/svn/trunk/stdint.h), but it otherwise
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| 100 | works fine. A project is easily created by adding all the *.h files and
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| 101 | all the *.cc files except diskio-unix.cc and sgdisk.cc.
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srs5694 | 08bb0da | 2010-02-19 17:19:55 -0500 | [diff] [blame] | 102 |
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srs5694 | 55d9261 | 2010-03-07 22:16:07 -0500 | [diff] [blame] | 103 | The MinGW compiler produces much larger executables than does the MS
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| 104 | compiler. The resulting binaries seem to work equally well, but my testing
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| 105 | has been minimal.
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| 106 |
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| 107 | I've also attempted to compile the code with OpenWatcom 1.8, but this
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| 108 | attempt failed, mostly because the compiler can't yet handle iostream
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| 109 | output on standard C++ strings. OpenWatcom also seems to have incorrectly
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| 110 | set the value of UINT32_MAX as if uint32_t values were 64-bit integers.
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| 111 | This alone won't cause the compile to fail, but it would create bugs.
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srs5694 | 91544e1 | 2010-01-28 21:10:36 -0500 | [diff] [blame] | 112 |
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| 113 | If you modify GPT fdisk to get it to compile under another compiler, I
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| 114 | welcome submission of patches.
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