Editing Disk image (section)

{{Short description|Computer file consisting of the contents of a storage device}}

A '''disk image''' is a snapshot of a [[computer storage|storage]] device's content {{endash}} typically stored in a [[computer file|file]] on another storage device.<ref name=":0">{{Cite book |date=2022-11-02 |chapter=Disk Imaging as a Backup Tool for Digital Objects |chapter-url=https://www.taylorfrancis.com/chapters/edit/10.4324/9781003034865-17/disk-imaging-backup-tool-digital-objects-eddy-colloton-jonathan-farbowitz-caroline-gil-rodr%C3%ADguez |title=Conservation of Time-Based Media Art |language=en |pages=204–222 |doi=10.4324/9781003034865-17|last1=Colloton |first1=Eddy |last2=Farbowitz |first2=Jonathan |last3=Rodríguez |first3=Caroline Gil |isbn=9781003034865 }}</ref><ref name=":3" /> 

Traditionally, a disk image was relatively large because it was a bit-by-bit copy of every storage location of a device (i.e. every sector of a [[hard disk drive]]), but it is now common to only store allocated data to reduce storage space.<ref name=":1">{{cite conference |url=https://www.sigops.org/s/conferences/sosp/2011/posters/summaries/sosp11-final15.pdf |last1=Pullakandam |first1=R. |last2=Lin |first2=X. |last3=Hibler |first3=M. |last4=Eide |first4=E. |last5=Ricci |first5=R. |title=High-performance Disk Imaging With Deduplicated Storage |conference=23rd ACM Symposium on Operating Systems Principles |date=October 23–26, 2011 |location=Cascais, Portugal}}</ref><ref>{{Citation |last=Kävrestad |first=Joakim |title=Vocabulary |date=2017 |url=https://doi.org/10.1007/978-3-319-67450-6_12 |work=Guide to Digital Forensics: A Concise and Practical Introduction |series=SpringerBriefs in Computer Science |pages=125–126 |editor-last=Kävrestad |editor-first=Joakim |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-67450-6_12 |isbn=978-3-319-67450-6 |access-date=2023-01-12|url-access=subscription }}</ref> [[Data compression|Compression]] and [[data deduplication|deduplication]] are commonly used to further reduce the size of image files.<ref name=":1" /><ref>{{Cite conference |last1=Lee |first1=Sang Su |last2=Kyong |first2=Un Sung |last3=Hong |first3=Do Won |date=2008 |title=A high speed disk imaging system |url=https://ieeexplore.ieee.org/document/4559553 |conference=2008 IEEE International Symposium on Consumer Electronics |pages=1–3 |doi=10.1109/ISCE.2008.4559553|s2cid=5932241 |url-access=subscription }}</ref> 

Disk imaging is performed for a variety of purposes including [[digital forensic]]s,<ref name=":2">{{Cite conference |last=Garfinkel |first=Simson L. |date=2009 |title=Automating Disk Forensic Processing with SleuthKit, XML and Python |url=https://ieeexplore.ieee.org/document/5341559 |conference=2009 Fourth International IEEE Workshop on Systematic Approaches to Digital Forensic Engineering |pages=73–84 |doi=10.1109/SADFE.2009.12|isbn=978-0-7695-3792-4 |s2cid=1624033 |hdl=10945/44249 |hdl-access=free }}</ref><ref name=":3">{{Cite conference |last1=Woods |first1=Kam |last2=Lee |first2=Christopher A. |last3=Garfinkel |first3=Simson |date=2011-06-13 |title=Extending digital repository architectures to support disk image preservation and access |url=https://doi.org/10.1145/1998076.1998088 |conference=Proceedings of the 11th Annual International ACM/IEEE Joint Conference on Digital Libraries |location=New York, NY, USA |publisher=Association for Computing Machinery |pages=57–66 |doi=10.1145/1998076.1998088 |isbn=978-1-4503-0744-4|s2cid=2628912 |hdl=10945/44252 |hdl-access=free }}</ref> [[cloud computing]],<ref>{{Cite conference |last1=Kazim |first1=Muhammad |last2=Masood |first2=Rahat |last3=Shibli |first3=Muhammad Awais |date=2013-11-26 |title=Securing the virtual machine images in cloud computing |url=https://doi.org/10.1145/2523514.2523576 |conference=Proceedings of the 6th International Conference on Security of Information and Networks |location=New York, NY, USA |publisher=Association for Computing Machinery |pages=425–428 |doi=10.1145/2523514.2523576 |isbn=978-1-4503-2498-4|s2cid=2474546 |url-access=subscription }}</ref> [[System administrator|system administration]],<ref name=":7">{{cite conference |last1=Blackham |first1=N. |last2=Higby |first2=C. |last3=Bailey |first3=M. |date=June 2004 |url=https://peer.asee.org/re-imaging-computers-for-multipurpose-labs |title=Re-Imaging Computers For Multipurpose Labs |conference=2004 American Society for Engineering Education Annual Conference |location=Salt Lake City, Utah |doi=10.18260/1-2--14125|doi-access=free }}</ref> [[backup]],<ref name=":0" /> and emulation for [[digital preservation]] strategy.<ref name=":4">{{Cite journal |last1=Day |first1=Michael |last2=Pennock |first2=Maureen |last3=May |first3=Peter |last4=Davies |first4=Kevin |last5=Whibley |first5=Simon |last6=Kimura |first6=Akiko |last7=Halvarsson |first7=Edith |date=2016 |title=The preservation of disk-based content at the British Library: Lessons from the Flashback project |url=http://journals.sagepub.com/doi/10.1177/0955749016669775 |journal=Alexandria: The Journal of National and International Library and Information Issues |language=en |volume=26 |issue=3 |pages=216–234 |doi=10.1177/0955749016669775 |s2cid=63617004 |issn=0955-7490|url-access=subscription }}</ref> 
Despite the benefits, storage costs can be high,<ref name=":1" /> management can be difficult<ref name=":2" /> and imaging can be time consuming.<ref name=":5">{{Cite book |last1=Stewart |first1=Dawid |url=http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-47045 |title=Need for speed : A study of the speed of forensic disk imaging tools |last2=Arvidsson |first2=Alex |date=2022}}</ref><ref name=":4" />

Disk images can be made in a variety of formats depending on the purpose. [[Virtual disk]] images (such as VHD and VMDK) are intended to be used for cloud computing,<ref>{{Cite journal |last1=Arunkumar |first1=G. |last2=Venkataraman. |first2=Neelanarayanan |date=2015-01-01 |title=A Novel Approach to Address Interoperability Concern in Cloud Computing |journal=Procedia Computer Science |series=Big Data, Cloud and Computing Challenges |language=en |volume=50 |pages=554–559 |doi=10.1016/j.procs.2015.04.083 |issn=1877-0509|doi-access=free }}</ref><ref>{{Cite journal |last1=Barrowclough |first1=John Patrick |last2=Asif |first2=Rameez |date=2018-06-11 |title=Securing Cloud Hypervisors: A Survey of the Threats, Vulnerabilities, and Countermeasures |journal=Security and Communication Networks |language=en |volume=2018 |pages=e1681908 |doi=10.1155/2018/1681908 |issn=1939-0114|doi-access=free }}</ref> [[ISO image]]s are intended to emulate optical media, such as a [[CD-ROM]].<ref name=":10">{{cite journal |last1=Colloton |first1=E. |last2=Farbowitz |first2=J. |last3=Fortunato |first3=F. |last4=Gil |first4=C. |date=2019 |url=https://resources.culturalheritage.org/emg-review/volume-6-2019-2020/colloton/ |title=Towards Best Practices In Disk Imaging: A Cross-Institutional Approach |journal=Electronic Media Review |volume=6}}</ref> [[IMG (file format)|Raw disk images]] are used for forensic purposes.<ref name=":3" /> Proprietary formats are typically used by disk imaging software.