1 GPT fdisk (aka gdisk) and FixParts 2 3 by Roderick W. Smith, rodsmith (a] rodsbooks.com 4 5 ******************************** IMPORTANT ******************************** 6 Most versions of Windows cannot boot from a GPT disk on BIOS-based 7 computers, and most varieties prior to Vista cannot read GPT disks. GPT 8 fdisk is a partition editor for GPT disks, and it will *AUTOMATICALLY 9 CONVERT* MBR disks to GPT form. Therefore, you should **NOT** use GPT fdisk 10 on a Windows system unless you fully understand what you're doing or are 11 certain that your computer boots in EFI/UEFI mode! If you accidentally use 12 GPT fdisk on a BIOS-mode boot disk, or perhaps even on a data disk, you may 13 find recovery to be very difficult! Pre-installed Windows 8 and later 14 systems almost always use GPT disks and boot in EFI/UEFI mode, but 15 self-installed Windows 8 systems sometimes use BIOS mode. This caveat does 16 not apply to FixParts, though; that tool works only on MBR disks. 17 *************************************************************************** 18 19 Read the main README file for general information on the program, and read 20 the gdisk.html or fixparts.html documents (the Linux man pages converted to 21 HTML format) for detailed use information. My GPT fdisk Web page, 22 http://www.rodsbooks.com/gdisk/, provides a more tutorial introduction to 23 the software. I originally wrote GPT fdisk on Linux, and some Linux- and 24 Unix-centric language remains in the documentation. 25 26 Windows Use Notes 27 ----------------- 28 29 The Windows version of GPT fdisk was added with version 0.6.2 of the 30 package. The Windows binary package includes the gdisk.exe interactive 31 text-mode program file but no equivalent to the sgdisk program that's 32 available with Linux, FreeBSD, and OS X builds. In theory, an sgdisk.exe 33 for Windows could be built if the popt library were installed. I've not 34 attempted to do this myself, though. If you care to try, check 35 http://gnuwin32.sourceforge.net/packages/popt.htm for information on popt 36 for Windows. 37 38 Beginning with version 0.8.10, I'm distributing both 32-bit and 64-bit 39 binaries, which include the strings "32" or "64" in their names. The 32-bit 40 binaries work fine on most versions of Windows, but some 64-bit 41 installations of Windows 8 lack 32-bit support libraries and so may need 42 the 64-bit binaries. 43 44 The FixParts program (fixparts32.exe and fixparts64.exe) is new with GPT 45 fdisk 0.7.0. As described in the main README file, this program fixes 46 certain partition table problems that can be created by buggy partitioning 47 software. Windows seems to be unfazed by most such problems, but I've not 48 done an extensive survey of Windows partitioning tools on this score. 49 50 To install the programs, copy the gdisk32.exe and fixparts32.exe (or 51 gdisk64.exe and fixparts64.exe) program files to any directory on your 52 path, such as C:\Windows. Alternatively, you can change to the program's 53 directory or type its complete path whenever you use it. 54 55 To use the programs, first launch a Command Prompt as the Administrator. To 56 do this, locate the Command Prompt program icon, right-click it, and select 57 "Run as Administrator." If you use a non-Administrator Command Prompt, you 58 won't be able to edit hard disk partition tables, although you will be able 59 to edit raw disk image files. 60 61 The program requires a hard disk identifier as an option. You can specify 62 this in either of two forms. The first way is as a number followed by a 63 colon, as in: 64 65 gdisk 0: 66 67 Disks are numbered starting from 0, so the preceding command launches gdisk 68 on the first disk. The second way to specify a disk device is via a 69 harder-to-remember name: 70 71 gdisk32 \\.\physicaldrive0 72 73 This command is equivalent to the earlier one -- it edits the partition 74 table on the first physical disk. Change the number at the end of the 75 device name to change the disk edited. 76 77 If you pass the "-l" option to gdisk.exe in addition to the disk 78 identifier, the program displays the current partition table information 79 and then exits. This use entails no risk to MBR disks, since the program 80 never writes data back to the disk when used in this way. 81 82 As noted above, editing the first disk with GPT fdisk is usually a Bad 83 Idea. An exception would be if your system uses an Extensible Firmware 84 Interface (EFI) and already boots from a GPT disk. It's safer to edit 85 non-boot disks, which usually have numbers of 1 and above, but only if you 86 run a version of Windows with GPT support. For more information on Windows' 87 support of GPT, see Microsoft's Web page on the topic: 88 89 http://www.microsoft.com/whdc/device/storage/GPT_FAQ.mspx 90 91 The Windows binaries I've compiled do not support Unicode UTF-16LE GPT 92 partition names. This feature was added to version 0.7.1 of the software 93 for Linux, FreeBSD, and OS X, and with changes to some #ifndef lines in the 94 source files, it can be compiled for Windows; however, it seems to do 95 little good in Windows because of Command Prompt window and/or ICU library 96 limitations. Thus, I've omitted this support in the interests of 97 simplifying the binary distribution, since including it would mean 98 distributing the ICU libraries. 99 100 Source Code and Compilation Issues 101 ---------------------------------- 102 103 I have successfully compiled GPT fdisk using three different Windows 104 compilers: 105 106 - MinGW (http://www.mingw.org), and in particular its Linux-hosted 107 cross-compiler -- Under Ubuntu Linux, the Makefile.mingw and 108 Makefile.mingw64 files enable compilation of the software via MinGW. 109 (Type "make -f Makefile.mingw" to compile 32-bit binaries, and "make -f 110 Makefile.mingw64" to compile 64-bit binaries.) If you try to compile 111 using another compiler or even using MinGW under Windows or another Linux 112 variety, you may need to adjust the Makefile.mingw options. 113 114 - Microsoft Visual C++ 2008 Express 115 (http://www.microsoft.com/express/Windows/) -- This compiler requires a 116 third-party stdint.h file (I used the one from 117 http://msinttypes.googlecode.com/svn/trunk/stdint.h), but it otherwise 118 works fine. A project is easily created by adding all the *.h files and 119 all the *.cc files except diskio-unix.cc, sgdisk.cc, and whichever 120 program file you intend to NOT build (gdisk.cc or fixparts.cc). 121 122 - Microsoft Visual C++ 2010 Express -- This compiler works much like the 123 2008 version, although I didn't need to add a third-party stdint.h file. 124 125 The MinGW compiler produces much larger executables than do the MS 126 compilers. The resulting binaries seem to work equally well, but my testing 127 has been minimal. 128 129 I've also attempted to compile the code with OpenWatcom 1.8, but this 130 attempt failed, mostly because the compiler can't yet handle iostream 131 output on standard C++ strings. OpenWatcom also seems to have incorrectly 132 set the value of UINT32_MAX as if uint32_t values were 64-bit integers. 133 This alone won't cause the compile to fail, but it would create bugs. 134 135 If you modify GPT fdisk to get it to compile under another compiler, I 136 welcome submission of patches. 137
