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Format

Apple Disk Image

Summary

Name
Apple Disk Image
Identifiers
  • MIME: application/x-apple-diskimage
  • Apple Uniform Type Identifier: com.apple.disk-image
  • PUID: fmt/1071
Format type
Aggregate
Description
The Apple Disk Image is a disk image format commonly used by the macOS operating system, and is distinct from the earlier Apple Disk Copy Image 4.2. Please contact the PRONOM team if you are able to provide a more thorough description of this format.
File extensions
dmg
Source
Datable / Datable
Developed by
Apple Computer, Inc.
Supported by
Apple Computer, Inc.

Relationships

Has priority over

Internal signatures

Apple Disk Image

Note
EOF, 512 offset - 'koly' block header, 4 byte version (0x00000004), 4 byte size of header (0x00000200)

Byte sequences

Min Frag Length
Absolute from EOF
Offset
500
Max offset
0
Byte Sequence
6B6F6C790000000400000200
Endianness
None

Changelog

  • Updated in V115

    Release date
    15 November 2023

    Apple Disk Image: Max-offset of 0 bytes added for EOF signature. Submitted by Digital Preservation Department, The National Archives (UK).

  • Updated in V108

    Release date
    5 September 2022

    Apple Disk Image: Given priority over fmt/1740 and x-fmt/268. Submitted by The Church of Jesus Christ of Latter-day Saints and The Royal Danish Library.

  • Added in V91

    Release date
    25 July 2017

    Apple Disk Image: Signature developed with Henk Vanstappen, Datable.

    Apple Disk Image: Full entry added. Submitted by Henk Vanstappen, Datable.