Optical disc image
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|
Filename extensions |
.iso, .udf |
---|---|
Internet media type |
application/vnd.efi.iso[1] |
Uniform Type Identifier (UTI) | public.iso-image |
Magic number | Volume descriptor: CD001 at 32769. NSR0 at 38913 or 32769 for UDF.[2] |
Type of format | Disk image |
Standard | ISO 9660, UDF |
An optical disc image (or ISO image, from the ISO 9660 file system used with CD-ROM media) 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.[3] ISO images contain the binary image of an optical media file system (usually ISO 9660 and its extensions or UDF), 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.
ISO images can be created from optical discs by
Description
Optical-disc images are uncompressed and do not use a particular container format; they are a
The .iso
ISO files store only the user data from each sector on an optical disc, ignoring the control headers and error correction data, and are therefore slightly smaller than a raw disc image of optical media. Since the size of the user-data portion of a sector (logical sector) in data optical discs is 2,048 bytes, the size of an ISO image will be a multiple of 2,048.
Any single-
With a suitable driver software, an ISO can be "mounted" – allowing the operating system to interface with it, just as if the ISO were a physical optical disc. Most Unix-based operating systems, including Linux and macOS, have this built-in capability to mount an ISO. Versions of Windows, beginning with Windows 8, also have such a capability.[4] For other operating systems, separately available software drivers can be installed to achieve the same objective.
Multiple-track images
A CD can have multiple
This also means that
Video CDs and Super Video CDs require at least two tracks on a CD, so it is also not possible to store an image of one of these discs inside an ISO image file, however an .IMG file can achieve this.
Formats such as
Most software that is capable of writing from ISO images to hard disks or recordable media (CD / DVD / BD) is generally not able to write from ISO disk images to flash drives. This limitation is more related to the availability of software tools able to perform this task, than to problems in the format itself. However, since 2011, various software has existed to write raw image files to USB flash drives.[5][6]
Uses
.ISO files are commonly used in
See also
References
- IANA. Retrieved 18 July 2023.
- ^ "File Signatures". www.garykessler.net. Archived from the original on 2020-07-03. Retrieved 2020-07-01.
- ^ Fisher, Tim (24 April 2018). "What Is an ISO File?". Lifewire. Archived from the original on 23 June 2018. Retrieved 23 June 2018.
- ^ "Windows 8 Explorer will support native mounting of ISO and VHD". ExtremeTech. Archived from the original on 2012-05-31. Retrieved 2012-05-21.
- ^ "ISO image to USB conversion". ISO to USB burning tool. Archived from the original on 15 February 2015. Retrieved 15 February 2015.
- ^ "How to Setup Windows 7 or Windows 8 from USB drive?". PowerISO. Archived from the original on 20 June 2016. Retrieved 15 February 2015.
- ^ "What dump formats are supported by Dolphin?". Dolphin Emulator Project. Archived from the original on 4 March 2017. Retrieved 11 March 2021.
- ^ "So how do I use it? - PCSX2". PCSX2 Team. Archived from the original on 9 March 2021. Retrieved 11 March 2021.