Editing Disk image (section)

==Background==

Disk images were originally (in the late 1960s) used for [[backup]] and [[disk cloning]] of mainframe disk media. Early ones were as small as 5 [[megabyte]]s and as large as 330 megabytes, and the copy medium was [[magnetic tape]], which ran as large as 200 megabytes per reel.<ref>{{cite web|title=IBM Mainframe Operating Systems|url=http://www.demorton.com/Tech/$OSTL.pdf|access-date=2014-06-17|url-status=dead|archive-url=https://web.archive.org/web/20140701185435/http://www.demorton.com/Tech/$OSTL.pdf|archive-date=2014-07-01}}</ref> Disk images became much more popular when floppy disk media became popular, where replication or storage of an exact structure was necessary and efficient, especially in the case of [[copy protected]] floppy disks.

Disk image creation is called disk imaging and is often time consuming, even with a fast computer, because the entire disk must be copied.<ref name=":5" /> Typically, disk imaging requires a third party disk imaging program or backup software. The software required varies according to the type of disk image that needs to be created. For example, RawWrite and WinImage create [[IMG (file format)|floppy disk image]] files for [[MS-DOS]] and [[Microsoft Windows]].<ref>{{Cite book |last=McCune |first=Mike |url=https://books.google.com/books?id=0SM3PEH9gagC&q=rawwrite&pg=PR1 |title=Integrating Linux and Windows |date=2000 |publisher=Prentice Hall Professional |isbn=978-0-13-030670-8 |language=en}}</ref><ref>{{Cite conference |last1=Li |first1=Hongwei |last2=Yin |first2=Changhong |last3=Xu |first3=Yaping |last4=Guo |first4=Qingjun |date=2010 |title=Construction of the Practical Teaching System on Operating Systems Course |url=https://ieeexplore.ieee.org/document/5458788 |conference=2010 Second International Workshop on Education Technology and Computer Science |volume=1 |pages=405–408 |doi=10.1109/ETCS.2010.184|isbn=978-1-4244-6388-6 |s2cid=15706012 }}</ref> In [[Unix]] or [[Unix-like|similar systems]] the [[dd (Unix)|dd]] program can be used to create raw disk images.<ref name=":3" /> [[Apple Disk Copy]] can be used on [[Classic Mac OS]] and [[macOS]] systems to create and write disk image files.

Authoring software for CDs/DVDs such as [[Nero Burning ROM]] can generate and load disk images for optical media. A ''virtual disk writer'' or ''virtual burner'' is a computer program that emulates an actual disc authoring device such as a CD writer or DVD writer. Instead of writing data to an actual disc, it creates a virtual disk image.<ref>{{cite web |title=Phantom Burner Overview |url=http://www.phantombility.com/en/prod/phantomburner/ |url-status=dead |archive-url=https://web.archive.org/web/20110819141722/http://phantombility.com/en/prod/phantomburner |archive-date=19 August 2011 |access-date=19 July 2011 |publisher=Phantombility, Inc}}</ref><ref>{{cite web |title=Virtual CD - The original for your PC |url=http://www.virtualcd.de/vcd/apps/overview/original.cfm?lg=0 |url-status=live |archive-url=https://web.archive.org/web/20110924022331/http://www.virtualcd.de/vcd/apps/overview/original.cfm?lg=0 |archive-date=24 September 2011 |access-date=19 July 2011 |work=Virtual CD website |publisher=H+H Software GmbH}}</ref> A virtual burner, by definition, appears as a disc drive in the system with writing capabilities (as opposed to conventional disc authoring programs that can create virtual disk images), thus allowing software that can burn discs to create virtual discs.<ref>{{cite web |title=Virtual CD/DVD-Writer Device |url=http://sourceforge.net/projects/virtualmedia/ |url-status=live |archive-url=https://web.archive.org/web/20110217075400/http://sourceforge.net/projects/virtualmedia/ |archive-date=17 February 2011 |access-date=19 July 2011 |work=[[SourceForge]] |publisher=Geeknet, Inc.}}</ref>