Disk Utility

Disk Utility

Developer(s)	Apple Inc.
Stable release	12 (346) / July 20, 2011
Operating system	Mac OS X
Type	Utility
License	Proprietary

Disk Utility is the name of a utility created by Apple for performing disk-related tasks in Mac OS X. These tasks include:^[1]

• the creation, conversion, compression and encryption of disk images from a wide range of formats read by Disk Utility to .dmg or—for CD/DVD images—.cdr, which is identical to the .iso format^{[citation needed]}; (in HFS+ format, not Windows compatible)
• mounting, unmounting, and ejecting disks (including both hard disks, removable media and disk images);
• enabling or disabling journaling;
• verifying a disk's integrity, and repairing it if the disk is damaged (this will work for both Mac compatible format partitions, and FAT-32 partitions with Microsoft Windows installed);
• verifying and repairing permissions^[2];
• disk erasing, formatting, partitioning^[3] and cloning;
• secure deletion of free space or disk using a "zero out" data, a 7-pass DOD 5220-22 M standard, or a 35-pass Gutmann algorithm
• adding or changing partition table between Apple Partition Table, GUID Partition Table, and master boot record (MBR);
• creating, destroying, merging^[4], and repairing RAID sets;
• restoring volumes from Apple Software Restore (ASR) images;
• burning disk images to CD or DVD in HFS+ format^[5];
• erasing CD-RWs and DVD-RWs;
• checking the S.M.A.R.T status of a hard disk.

Disk Utility functions may also be accessed from the Mac OS X command line with the diskutil and hdiutil commands.

Disk Utility was updated with Mac OS X v10.3. Prior to v10.3, the functionality of Disk Utility was spread across two applications: Disk Copy and Disk Utility. Disk Copy was used for creating and mounting disk image files, and Disk Utility was used for formatting, partitioning, verifying and repairing file structures. The ability to "zero" all data on a disk was not added until Mac OS X 10.2.3^[6]

Further changes introduced in 10.4.3 allowed Disk Utility to be used to verify the file structure of the current boot drive. However as Apple notes in their public knowledge base ^[7] doing so can sometimes yield false error messages.

Mac OS X v10.5 Leopard added the ability to create, resize, and delete disk partitions without erasing them, a feature known as live partitioning.

In versions of the Mac OS prior to Mac OS X, similar functionality to the verification features of Disk Utility could be found in the Disk First Aid application. Another application called Drive Setup was used for drive formatting and partitioning, and the application Disk Copy was used for working with disk images.

See also

• Logical Disk Manager
• Palimpsest Disk Utility
• GNU Parted
• diskpart
• fdisk
• cfdisk

References

1. ^ Disk Utility 10.5 Help: Testing and repairing a disk or volume
2. ^ About Disk Utility's Repair Disk Permissions feature
3. ^ Mac OS X 10.5: About resizing disk partitions
4. ^ Mac OS X: How to combine RAID sets in Disk Utility
5. ^ Burning a disk image file on a CD or DVD in Mac OS X
6. ^ Mac OS X: About the Mac OS X 10.2.3 Update
7. ^ Using Disk Utility in Mac OS X 10.4.3 or later to verify or repair disks