Fdisk For Mac Os X

by Rod Smith, [email protected]

  1. Gpt Fdisk For Mac Os X
  2. Fdisk Mac Os X
  3. Fdisk For Mac Os X 10 13 Download
  4. Mac Os X Update
  5. Fdisk For Mac Os X 10 11 Download Free

Disk Drill makes data recovery in Mac OS X super easy. With just one click of a button, it will run through all of its scanning functions and display a list of files that can be potentially recovered. You can even preview these files so that you can determine which ones can be successfully recovered. For Mac OS X: diskutil is a command-line tool for everything Mac OS X can handle, i.e. It will provide as much or more than Disk Utility can do graphically. For MS-DOS MBR (Master Boot Record) partitioned drives, use fdisk. For Apple APM (Apple Partition Map) partitioned drives, use pdisk. Mac OS X in a Nutshell by Get Mac OS X in a Nutshell now with O’Reilly online learning. O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.

Last Web page update: 2/17/2020, referencing GPT fdisk version 1.0.5

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GPT fdisk (consisting of the gdisk, cgdisk,sgdisk, and fixparts programs) is a set of text-modepartitioning tools for Linux, FreeBSD, Mac OS X, and Windows. Thegdisk, cgdisk, and sgdisk programs work onGlobally Unique Identifier (GUID) Partition Table (GPT) disks, rather thanon the older (and once more common) Master Boot Record (MBR)partition tables. The fixparts program repairs certain types ofdamage to MBR disks and enables changing partition types from primary tological and vice-versa. You can learn more about fixparts on its dedicated Web page. Ifgdisk, cgdisk, and sgdisk sound interesting toyou, then read on (or skip straight to the 'Obtaining GPT fdisk' link ifyou don't need the GPT pep talk). If you don't know what a GPT is, be sureto read the first section!

FreeBSD users: The FreeBSD version of GPT fdisk can'tnormally save changes to your partition table if any partition from thedisk is mounted. If you want to modify your FreeBSD boot disk, the safestway to do so is from an emergency system or from a dual boot to another OS.Alternatively, you can type sysctl kern.geom.debugflags=16at a shell prompt to enable FreeBSD to write to active disks. Thislimitation is shared by at least some other FreeBSD partitioning tools,such as gpt and FreeBSD's fdisk. This limitation doesnot exist in the Linux, Mac OS X, or Windows versions of thesoftware.

OS X 10.11 ('El Capitan') and later users: This versionof OS X adds a feature called System Integrity Protection (SIP), or lessformally, 'rootless.' This system blocks access to certain critical aspectsof the OS and hardware by third-party programs, including GPT fdisk. Thus,GPT fdisk's capabilities are limited under OS X 10.11 or later unless SIP isdisabled. Specifically, low-level access to the system disk is forbidden, soyou cannot repartition it. Access to USB flash drives remains possible,though. Disabling SIP is covered on several Web sites, including hereand here.My rEFInd boot manager candisable SIP, as described here. Alternatively, youcan run GPT fdisk from a Linux emergency disk.

Windows users: BIOS-mode version of Windows cannot bootfrom a GPT disk; Windows can boot from such disks only if the computer usesUnified Extensible Firmware Interface (UEFI) firmware. Versions prior toVista may not be able to read GPT disks at all. Since GPT fdiskautomatically turns MBR disks into GPT disks, you should use GPT fdisk onlyif you're positive your system can handle them. The vast majority ofcomputers sold with Windows 8 and later have UEFI firmware and so also useGPT. Consult Microsoft'sGPT FAQ for more information on Windows GPT support. If you have aBIOS-based computer and desperately need to boot from a GPT disk, consult myBIOS to UEFITransformation Web page.


  • What's a GPT?—A summary of basics about GPT
  • Working Around MBR's Limitations—A couple of ways to eek a bit more life out of MBR
  • Legacy BIOS Issues with GPT—Information on obscure issues related to BIOS/GPT coexistence
  • Why Use GPT fdisk?—Advice on when to use GPT fdisk vs. its alternatives
  • A gdisk Walkthrough—A demonstration of how to use GPT fdisk's interactive gdisk tool, which is a powerful tool for experts.
  • An cgdisk Walkthrough—A demonstration of how to use GPT fdisk's command-line cgdisk tool, which is easier to use for partitioning novices.
  • An sgdisk Walkthrough—A demonstration of how to use GPT fdisk's command-line gdisk tool, which is intended for use in scripts or by experts to do quick tasks.
  • Partitioning Advice—General suggestions on how to lay out your GPT partitions
  • Converting to or from GPT—If you want to convert an existing MBR or BSD disklabel disk to use GPT, or convert GPT to MBR, read this!
  • Wiping Out GPT Data—If you need to re-partition a GPT disk using MBR, read this first!
  • Booting from GPT—Advice on booting Linux, FreeBSD, Windows, and Mac OS X from GPT disks
  • Hybrid MBRs—Information on this non-standard, ugly, flaky, dangerous, but occasionally useful GPT variant.
  • Repairing GPT Disks—When a GPT disk's data structures are damaged, GPT fdisk can help you recover your data.
  • Obtaining GPT fdisk—How to get the program.
  • Revisions—GPT fdisk's revision history.

Man Pages

The Linux man pages for all of the GPT fdisk programs are availablehere:

Using GPT fdisk on Any Computer

At least three Linux emergency systems ship with GPT fdisk. You cancreate a bootable CD-R, boot it, and use GPT fdisk (and many other usefulLinux utilities) even on systems on which GPT fdisk doesn't compile. Thesetools are also very useful for Linux, FreeBSD, Mac OS X, Windows, and othersystems when things go wrong or when performing certain types of offlinemaintenance.

The emergency disks I know of that include GPT fdisk are:

Note that GPT fdisk is a Linux text-mode tool, so you'll need to knowat least a minimal amount about using a Linux text-mode shell. Many basicintroductions are available on the Web.You'll need to learn only enough to do very basic tasks; I've got a GPT fdisk walkthrough that describes GPT fdiskitself. Depending on your rescue CD and how you launched it, you may findyourself at a text-mode shell when you first boot, or you may need tolocate an item called 'Terminal,' 'Shell,' 'xterm,' or something similar tostart your text-mode shell.

Additional Resources

Fdisk For Mac Os X
  • GPT fdisk's Sourceforge page—The preferred download method for source code and non-Linux binaries. (For Linux binaries, see the 'Obtaining GPT fdisk' page.)
  • Intel's EFI page includes links to various EFI resources, including the EFI specifications, which include the official GPT 1.x specification. (In version 1.10, section describes GPT.) Note, however, that most PCs with EFI support use the newer UEFI 2.x (see next bullet point).
  • The UEFI 2.x specifications and tools detail UEFI 2.x, as implemented on some modern PC motherboards. The GPT structure is described in Section 5 (and especially Section 5.3) of the UEFI 2.7 specification. Note that UEFI 2.x uses the same GPT format (1.0) as described in version 1.x of the EFI specification, although the description has been clarified or expanded in a few areas. The GPT version number is unrelated to the EFI/UEFI version number.
  • 'Make the Most of Large Drives with GPT and Linux'—An informational piece on GPT I wrote for IBM developerWorks.
  • The Wikipedia entry on GPT—This has lots of useful technical information, including the most complete set of GUID partition codes I've seen in one place. (I implemented them all in gdisk, but there may be more by the time you read this.)
  • The Wikipedia entry on MBR—This has lots of useful technical information on MBR, should you want to compare it to the GPT information.
  • Apple's Technical Note TN2166—A document that provides technical details on GPT.
  • Microsoft's GPT FAQ—Go here to learn Windows-specific GPT information.
  • Microsoft's Recommended UEFI-Based Disk-Partition Configurations page provides details on how to partition a UEFI-based computer on which you want to install Windows.
  • Microsoft's MBR2GPT tool will convert a disk from MBR to GPT form, just as gdisk does. It also converts the Windows installation on the disk to boot in EFI/UEFI mode rather than the BIOS/CSM/legacy mode it had presumably been using.
  • A piece on Anandtech concerning the transition to 4096-byte sectors in hard disks.
  • Another of my IBM developerWorks articles, this time on using disks with 4096-byte sectors in Linux.
  • A page on repairing damage to GPT done by MacDrive under Windows. This page includes a simple Python utility to repair the damage, but of you can do the same thing with GPT fdisk.
  • A Web page I've written on recovering MBR disks that GNU Parted, GParted, and other libparted-based tools can't handle because of an improper extended partition definition.
  • Google's Chromium project Web page includes a page on disk formats, including information on how ChromeOS uses GPT disks.
  • My Web page on rEFInd, a boot loader project derived from the earlier rEFIt, covers this boot loader for EFI systems.
  • My Linux on UEFI: A Quick Installation Guide page provides helpful tips on how to install Linux on EFI-based systems.

If you have problems with or comments about this web page, pleasee-mail me at [email protected] Thanks.

Return to my main web page.


Partition table manipulator for Darwin UFS/HFS/DOS.

In order for the BIOS to boot the kernel, certain conventions must be adhered to. Sector 0 of a bootable hard disk must contain boot code, an MBR partition table, and a magic number (0xAA55). These MBR partitions (also known as BIOS partitions) can be used to break the disk up into several pieces. The BIOS loads sector 0 of the boot disk into memory, verifies the magic number, and begins executing the code at the first byte. The normal DOS MBR boot code searches the MBR partition table for an ``active' partition (indicated by a `*' in the first column), and if one is found, the boot block from that partition is loaded and executed in place of the original (MBR) boot block.

The automatic calculation of starting cylinder etc. uses a set of figures that represent what the BIOS thinks is the geometry of the drive. These figures are by default taken from the in-core disklabel, or values that /boot has passed to the kernel, but fdisk gives you an opportunity to change them if there is a need to. This allows the user to create a bootblock that can work with drives that use geometry translation under a potentially different BIOS.

If you hand craft your disk layout, please make sure that the OpenBSD partition starts on a cylinder boundary. (This restriction might be changed in the future.)

Editing an existing partition is risky, and can cause you to lose all the data in that partition.

You should run this program interactively once or twice to see how it works. This is completely safe as long as you answer the `write' questions in the negative.

There are subtleties fdisk detects that are not explained in this manual page. As well, chances are that some of the subtleties it should detect are being steamrolled. Caveat Emptor.


Gpt Fdisk For Mac Os X

List the current partitions:

$ sudo fdisk /dev/rdisk0

Fdisk Mac Os X

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Fdisk For Mac Os X 10 13 Download

Related macOS commands:

Mac Os X Update


Fdisk For Mac Os X 10 11 Download Free

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