Apple Disk Image is a disk image format commonly used by the macOS operating system. When opened, an Apple Disk Image is mounted as a volume within the Macintosh Finder.
(Redirected from DMG (file format))
File extension DMG is used by Apple Mac OS X Disk Image files. Mac OS X natively support DMG files with the bundled Apple Disk Utility, and can mount and treat them as though they are physical disk volumes. Mac OS Classic originally used the IMG file format for the same purposes, though this has now been superseded by DMG format.
An Apple Disk Image can be structured according to one of several proprietary disk image formats, including the Universal Disk Image Format (UDIF) and the New Disk Image Format (NDIF). An Apple disk image file's name usually has '.dmg' as its extension.
Features[edit]
Apple Disk Image files are published with a MIME type of application/x-apple-diskimage.
Different file systems can be contained inside these disk images, and there is also support for creating hybrid optical media images that contain multiple file systems.[1] Some of the file systems supported include Hierarchical File System (HFS), HFS Plus, File Allocation Table (FAT), ISO9660 and Universal Disk Format (UDF).[1][2]
Apple Disk Images can be created using utilities bundled with Mac OS X, specifically Disk Copy in Mac OS X v10.2 and earlier and Disk Utility in Mac OS X v10.3 and later. These utilities can also use Apple disk image files as images for burning CDs and DVDs. Disk image files may also be managed via the command line interface using the hdiutil utility.[3]
In Mac OS X v10.2.3, Apple introduced Compressed Disk Images[4] and Internet-Enabled Disk Images for use with the Apple utility Disk Copy, which was later integrated into Disk Utility in 10.3. The Disk Copy application had the ability to display a multi-lingual software license agreement before mounting a disk image. The image will not be mounted unless the user indicates agreement with the license.[5]
An Apple Disk Image allows secure password protection as well as file compression, and hence serves both security and file distribution functions; such a disk image is most commonly used to distribute software over the Internet.
History[edit]
Apple originally created its disk image formats because the resource fork used by Mac applications could not easily be transferred over mixed networks such as those that make up the Internet. Does the flame blade in 5e dmg have bonuses to hit and damage lyrics. Even as the use of resource forks declined with Mac OS X, disk images remained the standard software distribution format. Icloud download mac. Disk images allow the distributor to control the Finder's presentation of the window, which is commonly used to instruct the user to copy the application to the correct folder.
A previous version of the format, intended only for floppy disk images, is usually referred to as 'Disk Copy 4.2' format, after the version of the Disk Copy utility that was used to handle these images.[1] A similar format that supported compression of floppy disk images is called DART.[1][6]
New Disk Image Format (NDIF) was the previous default disk image format in Mac OS 9,[1] and disk images with this format generally have a .img (not to be confused with raw .img disk image files) or .smi file extension. Files with the .smi extension are actually applications that mount an embedded disk image, thus a 'Self Mounting Image', and are intended only for Mac OS 9 and earlier.[7][2]
Universal Disk Image Format (UDIF) is the native disk image format for Mac OS X. Disk images in this format typically have a .dmg extension.[1]
File format[edit]
Apple has not released any documentation on the format, but attempts to reverse engineer parts of the format have been successful. The encrypted layer was reverse engineered in an implementation called VileFault[8] (a spoonerism of FileVault).
Apple disk image files are essentially raw disk images (i.e. contain block data) with some added metadata, optionally with one or two layers applied that provide compression and encryption. In hdiutil these layers are called CUDIFEncoding and CEncryptedEncoding.[1]
UDIF supports ADC (an old proprietary compression format by Apple), zlib, bzip2 (as of Mac OS X v10.4), and LZFSE (as of Mac OS X v10.11)[9] compression internally.
Trailer[edit]
The trailer can be described using the following C structure.[10] All values are big-endian (PowerPC byte ordering)
Here is an explanation: How to download bootcamp on mac.
Utilities[edit]![]()
There are few options available to extract files or mount the proprietary Apple Disk Image format. Some cross-platform conversion utilities are:
In Windows, most dmg images can be opened using several other programs such as UltraISO and IsoBuster. MacDrive can also mount simple dmg files as drives under windows, but not sparse disk or encrypted dmgs.[13] A free Apple DMG Disk Image Viewer also exists.[14]
In Linux and possibly other Unix flavors, most .dmg files can be burned to CD/DVD using any CD-burner program (using cdrecord directly or a front-end such as K3B or Brasero) or directly mounted to a mountpoint (e.g.
mount -o loop,ro -t hfsplus imagefile.dmg /mnt/mountpoint ).[15][16] darling-dmg is a FUSE module enabling easy DMG file mounting on Linux.[17]
See also[edit]References[edit]
External links[edit]
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Apple_Disk_Image&oldid=917998972'
1 extension(s) and 0 alias(es) in our database
Below, you can find answers to the following questions:
Mac OS X Disk Image
DMG file is a Mac OS X disk image. You can burn it or just mount it in a virtual drive.
Category: Disk Image files
Application:Mac OS X Disk Copy
Mime-type: application/octet-stream
Magic string (ASCII): -
-
UltraISO
CDRWIN Binary Data File
WinImage Disk Image
ISO 9660 Cd-Rom Disk Image
Direct Access Archive
CloneCD Sub Channel Data
Other types of files may also use the .dmg file extension. If you have helpful information about .dmg extension, write to us!
What Is Dmg Extension For WindowsIs it possible that the filename extension is misspelled?
We found the following similar extensions in our database:
Chessmaster Saved Game
SAS Stat Studio Metadata
myPM Merge Data
Digital Multimedia Broadcasting File
3DVIA Composer Model
DJGPP Makefile
Digital Negative Image
NBA 2K12 Saved Game
BrainVoyager QX Diffusion-Weighted Project
The .dmg filename extension is often given incorrectly!File Extension Dmg Free Download
According to the searches on our site, these misspellings were the most common in the past year:
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Can't open a .dmg file?
If you want to open a .dmg file on your computer, you just need to have the appropriate program installed. https://zmmnlm.weebly.com/rome-total-war-2-mac-download.html. If the .dmg association isn't set correctly, you may receive the following error message:
Windows can't open this file:
File: example.dmg To open this file, Windows needs to know what program you want to use to open it. Windows can go online to look it up automatically, or you can manually select from a list of programs that are installed on your computer. What Is Dot Dmg File ExtensionTo change file associations:
Supported operating systems
Windows Server 2003/2008/2012/2016, Windows 7, Windows 8, Windows 10, Linux, FreeBSD, NetBSD, OpenBSD, Mac OS X, iOS, Android
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