ISO 9660 is a file system for optical disc media. The file system is an international standard available from the International Organization for Standardization (ISO). Since the specification is available for anybody to purchase, implementations have been written for many operating systems.
JPEG 2000 (JP2) is an image compression standard and coding system. It was developed from 1997 to 2000 by a Joint Photographic Experts Group committee chaired by Touradj Ebrahimi, with the intention of superseding their original JPEG standard, which is based on a discrete cosine transform (DCT), with a newly designed, wavelet-based method. The standardized filename extension is .jp2 for ISO/IEC 15444-1 conforming files and .jpx for the extended part-2 specifications, published as ISO/IEC 15444-2. The registered MIME types are defined in RFC 3745. For ISO/IEC 15444-1 it is image/jp2.
A disk image is a snapshot of a storage device's structure and data typically stored in one or more computer files on another storage device. Traditionally, disk images were bit-by-bit copies of every sector on a hard disk often created for digital forensic purposes, but it is now common to only copy allocated data to reduce storage space. Compression and deduplication are commonly used to reduce the size of the image file set. Disk imaging is done for a variety of purposes including digital forensics, cloud computing, system administration, as part of a backup strategy, and legacy emulation as part of a digital preservation strategy. Disk images can be made in a variety of formats depending on the purpose. Virtual disk images are intended to be used for cloud computing, ISO images are intended to emulate optical media and raw disk images are used for forensic purposes. Proprietary formats are typically used by disk imaging software. Despite the benefits of disk imaging the storage costs can be high, management can be difficult and they can be time consuming to create.
A live CD is a complete bootable computer installation including operating system which runs directly from a CD-ROM or similar storage device into a computer's memory, rather than loading from a hard disk drive. A live CD allows users to run an operating system for any purpose without installing it or making any changes to the computer's configuration. Live CDs can run on a computer without secondary storage, such as a hard disk drive, or with a corrupted hard disk drive or file system, allowing data recovery.
An optical disc image is a disk image that contains everything that would be written to an optical disc, disk sector by disc sector, including the optical disc file system. ISO images are expected to contain the binary image of an optical media file system, including the data in its files in binary format, copied exactly as they were stored on the disc. The data inside the ISO image will be structured according to the file system that was used on the optical disc from which it was created.
Optical disc authoring, including CD, DVD, and Blu-ray Disc authoring, is the process of assembling source material—video, audio or other data—into the proper logical volume format to then be recorded ("burned") onto an optical disc. This act is usually done illegally, by pirating copyrighted material without permission from the original artists.
A cue sheet, or cue file, is a metadata file which describes how the tracks of a CD or DVD are laid out. Cue sheets are stored as plain text files and commonly have a .cue filename extension. CDRWIN first introduced cue sheets, which are now supported by many optical disc authoring applications and media players.
IMG, in computing, refers to binary files with the .img filename extension that store raw disk images of floppy disks, hard drives, and optical discs or a bitmap image – .img.
A CloneCD Control File is a text descriptor with the extension .ccd used by CloneCD to mark the properties of a CD/DVD image. These files need to be combined with an image file to be burned. It may also come with a subchannel file.
In Unix-like operating systems, a loop device, vnd, or lofi is a pseudo-device that makes a computer file accessible as a block device.
An NRG file is a proprietary optical disc image file format originally created by Nero AG for the Nero Burning ROM utility. It is used to store disc images. Other than Nero Burning ROM, however, a variety of software titles can use these image files. For example, Alcohol 120%, or Daemon Tools can mount NRG files onto virtual drives for reading.
Brasero is a free and open-source disc-burning program for Unix-like operating systems, it serves as a graphical front-end to cdrtools, cdrskin, growisofs, and (optionally) libburn. Licensed under the terms of the GNU General Public License.
Media Descriptor File (MDF) is a proprietary disc image file format developed for Alcohol 120%, an optical disc authoring program. Daemon Tools, CDemu, MagicISO, PowerDVD, and WinCDEmu can also read the MDF format. A disc image is a computer file replica of the computer files and file system of an optical disc.
MagicISO is a CD/DVD image shareware utility that can extract, edit, create, and burn disc image files. It offers the possibility of converting between ISO and CUE/BIN and their proprietary Universal Image Format disc image format.
A CD-ROM is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both computer data and audio with the latter capable of being played on a CD player, while data is only usable on a computer.
Notable software applications that can access or manipulate disk image files are as follows, comparing their disk image handling features.
AcetoneISO is a free and open-source virtual drive software to mount and manage image files. Its goals are to be simple, intuitive and stable. Written in Qt, this software is meant for all those people looking for a "Daemon Tools for Linux". However, AcetoneISO does not emulate any copy protection while mounting.
Chasys Draw IES is a suite of applications including a layer-based raster graphics editor with adjustment layers, linked layers, timeline and frame-based animation, icon editing, image stacking and comprehensive plug-in support, a fast multi-threaded image file converter and a fast image viewer, with RAW image support in all components. It supports the native file formats of several competitors including Adobe Photoshop, Affinity Photo, Corel Photo-Paint, GIMP, Krita, Paint.NET and PaintShop Pro, and the whole suite is designed to make effective use of multi-core processors, touch-screens and pen-input devices.
DAEMON Tools is a virtual drive and optical disc authoring program for Microsoft Windows and Mac OS.
