Disk image emulator

A disk image emulator is computer software designed to mount a disk image, usually of a CD or DVD, from a local hard drive or USB flash drive. The mounting is usually done by creating a virtual drive on the system, that to the operating system looks like an ordinary disk drive, in other words disc reading hardware is substituted with disc images.

Some operating systems such as Linuxcite web |url= http://www.linuxhelp.net/linux_downloads/ |title= Linux ISO Images |publisher= LinuxHelp.net |accessdate= 2007-03-23 ] and Mac OS XAlthough OS X's built-in DiskImageMounter software does not emulate a physical drive] have this functionality built-in (see loop device), while others such as Microsoft Windows require additional software.

Uses

* Enables users to avoid constantly switching out discs
* Helps prevent scratching, which can cause permanent damage to a disc
* Speeds up access times as hard drives are faster than optical drives
* Provides a backup copy of a disc, in case the original becomes damaged, lost, or stolen
* Enables users to carry large disc libraries without the physical burden of the discs
* Emulates multiple disks, which is useful for installing or using software that shipped on multiple disks
* Can make a disc accessible to users on a network, which is very practical when it is impossible to distribute the discs to all of the users on a network
* Allows programs that can normally only work with optical discs (like some DVD-Video applications) to access data on a hard drive
* For often-used CD and DVD discs, where simply copying the disc to a hard drive won't work
* A CD/DVD master used to burn physical discs
* Make disc accessible to machines without disc drive
* Save power by turning off disc drive, for instance on laptops
* Makes the computer quieter, many removable disc drives are noisier than hard disks
* Security; disk images can be encrypted, and decrypted only when accessed

Encryption

Some emulator software, such as FreeOTFE and Sentry 2020 are designed to emulate a hard drive, and encrypt the disk image stored. This provides an easy to use, and secure, means of encrypting files in bulk by simply storing files on the virtual drive which is created when the disk image is mounted.

This form of disk emulation is often referred to as "OTFE" (on-the-fly encryption)

oftware distribution

After the spread of broadband, CD and DVD disk images became a common medium for Linux distributionscite web |url= http://www.linuxhelp.net/linux_downloads/ |title= Linux ISO Images |publisher= LinuxHelp.net |accessdate= 2007-03-23 ] . Online data and bootable recovery CD images are provided for customers of certain commercial software companies.cite web |url= http://www.drive-backup.com/glossary/recovery_cd.htm |title= Drive Backup 7.0 |publisher= Paragon Software GmbH |accessdate= 2007-03-23 |quote= Recovery CD self-burning ISO image is available for download online to all registered customers of Paragon products. ]

Disk image emulator software

*CD/DVD
** AcetoneISO (Linux)
** Alcohol 120%
** CDemu (Linux)
** Daemon Tools (freeware/adware, ads are opt-out)
** DiskImageMounter (Mac OS only)
** Furius ISO Mount (Linux)
** GameDrive
** ImageMapper
** MagicISO and freeware MagicDisc
** Microsoft Virtual CD-ROM Control Panelcite web |url= http://support.microsoft.com/kb/916902 |title= How to customize Windows PE by using the source files that are included with the Microsoft SMS 2003 Operating System Deployment (OSD) Feature Pack |work= Microsoft Knowledge Base |publisher= Microsoft |date= 2006-10-30 |accessdate= 2007-03-23 ]
** Nero ImageDrive
** PowerISO
** Toast Titanium
** UltraISO
** VCDMount - A simple command-line CD emulator for all Unix-like systems
** Virtual CloneDrive (freeware)
** VirtualCD
** WinMount

*Hard drive
** FreeOTFE (opensource, encrypted disk image)
** Sentry 2020 (commercial, encrypted disk image)
** BestCrypt (commercial, encrypted disk image)
** TrueCrypt (opensource, encrypted disk image)

ee also

* Copy protection
** CD/DVD copy protection
* Read-only memory
* Loopback device
* Virtual CloneDrive
* Virtual drive

Footnotes