| GPT fdisk (aka gdisk) |
| by Roderick W. Smith, rodsmith@rodsbooks.com |
| |
| Introduction |
| ------------ |
| |
| This software is intended as a (somewhat) fdisk-workalike program for |
| GPT-partitioned disks. Although libparted and programs that use it (GNU |
| Parted, gparted, etc.) provide the ability to handle GPT disks, they have |
| certain limitations that gdisk overcomes. Specific advantages of gdisk |
| include: |
| |
| * The ability to convert MBR-partitioned disks in-place to GPT format, |
| without losing data |
| |
| * The ability to convert BSD disklabels in-place to create GPT |
| partitions, without losing data |
| |
| * The ability to specify sector-exact partition sizes |
| |
| * More flexible specification of filesystem type code GUIDs, which |
| GNU Parted tends to corrupt (particularly for FAT partitions) |
| |
| * Clear identification of the number of unallocated sectors on a |
| disk |
| |
| * A user interface that's familiar to long-time users of Linux |
| fdisk |
| |
| * The MBR boot loader code is left alone (GNU Parted tends to |
| wipe it out with every change) |
| |
| * The ability to create a hybrid MBR, which permits GPT-unaware |
| OSes to access up to three GPT partitions on the disk |
| |
| Of course, gdisk isn't without its limitations. Most notably, it lacks the |
| filesystem awareness and filesystem-related features of GNU Parted. You |
| can't resize a partition's filesystem or create a partition with a |
| filesystem already in place with gdisk, for instance. There's no GUI |
| version of gdisk. |
| |
| Installing |
| ---------- |
| |
| To compile gdisk, you must have appropriate development tools installed, |
| most notably the GNU Compiler Collection (GCC) and its g++ compiler for |
| C++. The sgdisk program also requires the popt library and its development |
| files (headers). Most Linux distributions install popt by default, but you |
| may need to install a package called popt-dev, popt-devel, or something |
| similar to obtain the development libraries. Mac OS users can find a version |
| of popt for Mac OS from http://popt.darwinports.com; however, you'll first |
| need to install DarwinPorts (instructions exist on the preceding page). |
| Alternatively, you can compile gdisk alone, without sgdisk; gdisk doesn't |
| require popt. |
| |
| When all the necessary development tools and libraries are installed, you |
| can uncompress the package and type "make" at the command prompt in the |
| resulting directory. The result should be program files called gdisk and |
| sgdisk. Typing "make gdisk" or "make sgdisk" will compile only the requested |
| programs. You can use these programs in place or copy the files to a |
| suitable directory, such as /usr/local/sbin. You can copy the man pages |
| (gdisk.8 and sgdisk.8) to /usr/local/man/man8 to make them available. |
| |
| Caveats |
| ------- |
| |
| THIS SOFTWARE IS BETA SOFTWARE! IF IT WIPES OUT YOUR HARD DISK OR EATS YOUR |
| CAT, DON'T BLAME ME! To date, I've tested the software on several USB flash |
| drives, a handful of PATA and SATA hard disks, and several virtual disks in |
| a QEMU environment. I believe all data-corruption bugs to be squashed, but |
| I know full well that the odds of my missing something are high. This is |
| particularly true for large drives; my only direct testing with such disks |
| is with virtual QEMU disks. I've received user reports of success with |
| RAID arrays over 2TiB in size, though. |
| |
| My main development platform is a system running the 64-bit version of |
| Ubuntu 8.04. I've also tested on 64-bit OpenSuSE, 32-bit Fedora 10, 32-bit |
| Fedora 11, 32-bit Ubuntu 6.10, 64-bit Ubunut 9.10, 64-bit Gentoo, 32-bit |
| PowerPC Debian Linux, 32-bit Intel-based Mac OS X 10.5 and 10.6, and 64-bit |
| FreeBSD 7.1. Problems relating to 64-bit integers on the 32-bit Linux have |
| been common during development and may crop up in the future. The Mac OS X, |
| FreeBSD, and big-endian (PowerPC) support are new. |
| |
| Redistribution |
| -------------- |
| |
| This program is licensed under terms of the GNU GPL (see the file COPYING). |
| |
| Acknowledgements |
| ---------------- |
| |
| This code is mostly my own; however, I've used three functions from two |
| other GPLed programs: |
| |
| - The code used to generate CRCs is taken from the efone program by |
| Krzysztof Dabrowski and ElysiuM deeZine. (See the crc32.h and |
| crc32.cc source code files.) |
| |
| - A function to find the disk size is taken from Linux fdisk by |
| A. V. Le Blanc. |
| |
| Additional code contributors include: |
| |
| - Yves Blusseau (1otnwmz02@sneakemail.com) |
| |
| - David Hubbard (david.c.hubbard@gmail.com) |