• QR code (abbreviated from -Quick Response code-) is the trademark for a type of matrix barcode (or two-dimensional barcode) first designed in 1994 for the automotive industry in Japan. A barcode is a machine-readable optical label that contains information about the item to which it is attached.
• ↑ Sion's profile page at LeagueOfLegends.com. Sion's current stats doesn't need any buffs. As a Sion main 'Hetsugane' in PH, I can confidently say that Sion can overwh.

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.

% max hp true dmg is dumb. There was already a type of champion made to kill tanks: they are called adc. They don't need true dmg to kill tanks they only need some buffs Then they start killing everything else too and start thinking they're good players. You don't want to give ADC players reasons to think they're good, they're annoying enough.

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]

What Is Sions Default Dmg Type 10

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. Even as the use of resource forks declined with Mac OS X, disk images remained the standard software distribution format. 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:

Utilities[edit]

There are few options available to extract files or mount the proprietary Apple Disk Image format. Some cross-platform conversion utilities are:

• dmg2img was originally written in Perl; however, the Perl version is no longer maintained, and the project was rewritten in C. Currently, without additional tools, the resulting images may be mounted only under Mac OS X and under Linux (provided hfsplus support has been enabled). UDIF ADC-compressed images have been supported since version 1.5.^[11]
• DMGEXtractor is written in Java with GUI, and it supports more advanced features of dmg including AES-128 encrypted images but not UDCO images.^[12]
• 7-Zip, including the free cross-platform port of its command-line interface, p7zip.

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]

1. ^ ^abcdefg'hdiutil(1) Mac OS X Manual Page'. Archived from the original on 2016-05-14. Retrieved 2016-05-14.
2. ^ ^ab'Mac OS X: Using Disk Copy disk image files'. Archived from the original on 2013-12-19. Retrieved 2013-04-25.
3. ^hdiutil(1) – Darwin and macOS General Commands Manual
4. ^'Re: Some apps refuse to launch in 10.2.8! (OT, but very important)'. Archived from the original on 2014-01-17.
5. ^'Guides'. Apple. Archived from the original on 2009-03-06. Retrieved 2010-10-27.
6. ^'DART 1.5.3: Version Change History'. Archived from the original on 2013-12-19. Retrieved 2013-04-25.
7. ^'Software Downloads: Formats and Common Error Messages'. Archived from the original on 2010-12-24. Retrieved 2009-05-06.
8. ^'VileFault'. 2006-12-29. Archived from the original on 2007-01-09. Retrieved 2010-10-27.
9. ^Michael Tsai (2015-10-07). 'LZFSE Disk Images in El Capitan'. Archived from the original on 2017-04-09. Retrieved 2017-04-09.
10. ^'Demystifying the DMG File Format'. Archived from the original on 2013-03-17.
11. ^'dmg2img'. Archived from the original on 29 November 2010. Retrieved 2010-10-27.
12. ^'DMGExtractor'. Archived from the original on 2011-01-02. Retrieved 2011-01-03.
13. ^MacDrive Features / Boot Camp / System Requirements /. 'MacDrive Home page'. Mediafour. Archived from the original on 4 October 2010. Retrieved 2010-10-27.
14. ^Olivia Dehaviland (2015-03-03). 'Apple DMG Disk Image Viewer'. DataForensics.org. Archived from the original on 2015-04-02. Retrieved 2015-03-10.
15. ^'How To Convert DMG To ISO in Windows, Linux & Mac'. Archived from the original on 2010-03-07.
16. ^'Convert DMG To ISO using PowerISO'. Archived from the original on 2009-05-02. Retrieved 2009-02-15.
17. ^'darling-dmg'. darling-dmg. Retrieved 29 March 2015.

External links[edit]

• Apple Developer Connection A Quick Look at PackageMaker and Installer
• O'Reilly Mac DevCenter Tip 16-5. Create a Disk Image from a Directory in the Terminal

What Is Sions Default Dmg Type 2

Manipulate disk images (attach, verify, burn, etc).

Disk images are containers that emulate disks. Like disks, they can be partitioned and formatted. Many uses of disk images blur the distinction between the disk image container and its content, but this distinction is critical to understanding disk images. The terms 'attach' and 'detach' are used to distinguish the way disk images are connected to and disconnected from the system.
For example, when you double-click a disk image in the macOS Finder, two separate things happen. First, the image is 'attached' to the system just like an external drive. Then, the kernel and Disk Arbitration probe the new device for recognized file structures. If any file structures are understood, the associated volumes will mount and appear in the
Finder.
Always consider whether a 'disk image' operation applies to the blocks of the disk image device or to the (often file-oriented) content of the image. For example, verify verifies that the blocks stored in a read- only disk image have not changed since it was created. On the other hand, create -srcfolder creates a disk image container, puts a filesystem
in it, and then copies the specified files to the new filesystem.

As of macOS 10.5, a more reliable, efficient, and scalable sparse format, UDSB (SPARSEBUNDLE), is recommended for persistent sparse images as long as a backing bundle (directory) is acceptable. macOS 10.5 also introduced
F_FULLFSYNC over AFP (on client and server), allowing proper journal flushes for HFS+J-bearing images. Critical data should never be stored in sparse disk images on file servers that don't support F_FULLFSYNC.
SPARSE (UDSP) images and shadow files were designed for intermediate use when creating other images (e.g. UDZO) when final image sizes are unknown. As of macOS 10.3.2, partially-updated SPARSE images are properly handled and are thus safe for persistent storage. SPARSE images are not recommended for persistent storage on versions of macOS earlier than 10.3.2 and should be avoided in favor of SPARSEBUNDLE images or UDRW
images and resize.
If more space is needed than is referenced by the hosted filesystem, hdiutil resize or diskutil(8) resize can help to grow or shrink the filesystem in an image. compact reclaims unused space in sparse images. Though they request that hosted HFS+ filesystems use a special 'front first' allocation policy, beware that sparse images can enhance the
effects of any fragmentation in the hosted filesystem.
To prevent errors when a filesystem inside of a sparse image has more free space than the volume holding the sparse image, HFS volumes inside sparse images will report an amount of free space slightly less than the amount of free space on the volume on which image resides. The image filesystem currently only behaves this way as a result of a direct attach action and will not behave this way if, for example, the filesystem is unmounted and remounted.

/dev Entry Access

Since any /dev entry can be treated as a raw disk image, it is worth noting which devices can be accessed when and how. /dev/rdisk nodes are character-special devices, but are 'raw' in the BSD sense and force block-aligned I/O. They are closer to the physical disk than the buffer cache. /dev/disk nodes, on the other hand, are buffered block-special
devices and are used primarily by the kernel's filesystem code.
It is not possible to read from a /dev/disk node while a filesystem is mounted from it, but anyone with read access to the appropriate /dev/rdisk node can use hdiutil verbs such as fsid or pmap with it. The DiskImages framework will attempt to use authopen(1) to open any device which it can't open (due to EACCES) for reading with open(2). This might cause apparent hangs while trying to access /dev entries while logged in remotely (an authorization panel is waiting on console).
Generally, the /dev/disk node is preferred for imaging devices (e.g. convert or create -srcdevice operations), while /dev/rdisk is usable for the quick pmap or fsid. In particular, converting the blocks of a mounted journaled filesystem to a read-only image will prevent the volume in the image from mounting (the journal will be permanently dirty).

Compatibility

macOS 10.0 supported the disk images of Disk Copy 6 on Mac OS 9. macOS 10.1 added sparse, encrypted, and zlib-compressed images. These images will not be recognized on macOS 10.0 (or will attach read/write, possibly allowing for their destruction). As the sparse, shadow, and encrypted formats have evolved, switches have been added to facilitate the creation of images that are compatible with older OS versions (at the expense of the performance and reliability improvements offered by the format enhancements). In particular, sparse images should not be expected to attach on versions of macOS older than that which created them.
With macOS 10.2, the most common image formats went 'in-kernel' (i.e. the DiskImages kernel extension served them without a helper process), image meta-data began being stored both as XML and in the embedded resource fork, and the default Disk Copy.app 'compressed' format became UDZO (breaking compatibility with 10.0). macOS 10.4 introduced bzip2 compression in the UDBZ format which provides smaller images (especially when combined with makehybrid) at the expense of backwards compatibility.
In macOS 10.4.7, the resource forks previously embedded in UDIF images were abandoned entirely to avoid metadata length limitations imposed by resource fork structures. As a result, UDIF images created on 10.4.7 and later will not, by default, be recognized by either macOS 10.1 or macOS 10.0. flatten can be used to customize the type of metadata stored in the image.
macOS 10.5 introduced sparse bundle images which compact quickly but are not recognized by previous OS versions. macOS 10.6 removed support for attaching SPARSEBUNDLE images from network file servers that don't support F_FULLFSYNC.
macOS 10.7 removed double-click support for images using legacy metadata; these can be rehabilitated using flatten and unflatten, or convert.

History

Disk images were first invented to electronically store and transmit representations of floppy disks for manufacturing replication. These images of floppies are typically referred to as 'Disk Copy 4.2' images, in reference to the application that created and restored them to floppy disks. Disk Copy 4.2 images were block-for-block representations of a floppy
disk, with no notion of compression. DART is a variant of the Disk Copy 4.2 format that supported compression.
NDIF (New Disk Image Format) images were developed to replace the Disk Copy 4.2 and DART image formats and to support images larger than a floppy disk. With NDIF and Disk Copy version 6, images could be'attached' as mass storage devices under Mac OS 9. Apple Data Compression (ADC) -- which carefully optimizes for fast decompression -- was
used to compress images that were typically created once and restored many times during manufacturing.
UDIF (Universal Disk Image Format) device images picked up where NDIF left off, allowing images to represent entire block devices and all the data therein: DDM, partition map, disk-based drivers, etc. For example, it can represent bootable CDs which can then be replicated from an image.
To ensure single-fork files (NDIF was dual-fork), it began embedding its resource fork in the data fork. UDIF is the native image format for OS X.
Raw disk images from other operating systems (e.g. .iso files) will be recognized as disk images and can be attached and mounted if macOS recognizes the filesystems. They can also be burned with hdiutil burn.

What's New

In macOS 10.12 Apple will provide an updated hdutil command able to work with the new file system.

macOS 10.7 added the ability to quickly render encrypted images inaccessible using the new erasekeys verb, which saves time versus securely overwriting the entire image.
In macOS 10.6, pmap was rewritten to use MediaKit's latest reporting routines so that it can properly support GPT partition maps. Also -debug now implies -verbose for all verbs.
macOS 10.5 changed the behavior of attach when run on an existing image or /dev node: if the image was attached but no volume was mounted, the volume would be mounted. Prior systems would return the /dev without mounting the volume. This change effectively removes the ability to create a second /dev node from an existing one.

Examples

Mount a Disk Image:
$ hdiutil attach /path/to/diskimage.dmg

Unmount a Disk Image:
$ hdiutil detach /dev/disk2s1

What Is Sions Default Dmg Type 5

Create a Disk Image from a folders contents:
$ hdiutil create -volname 'Volume Name' -srcfolder /path/to/folder -ov diskimage.dmg

Create an encrypted Disk Image from a folders contents:
$ hdiutil create -encryption -stdinpass -volname 'Volume Name' -srcfolder /path/to/folder -ov encrypted.dmg

The required password can be piped into the hdiutil command:
echo -n SEcurePa$$w0rd | hdiutil...

What Is Sions Default Dmg Types

Burn a Disk Image file (.iso, .img or .dmg) to a DVD:
$ hdiutil burn /path/to/image_file

“The beginning of wisdom is to call things by their right names” - Chinese Proverb

Related macOS commands:

What Is Sions Default Dmg Type 1

asr - Apple Software Restore.
dd - Convert and copy a file, clone disks.
diskutil - Disk utilities - Format, Verify, Repair.
ditto - Copy files and folders.
authopen(1), hdid(8), ioreg(8), drutil(1), msdos.util(8), hfs.util(8), diskarbitrationd(8), /System/Library/CoreServices/DiskImageMounter.app.

What Is Sions Default Dmg Type 8