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A .ISO is a digital copy of a cd or dvd. Almost 90% of all digital copys end on ".ISO". Why is this? Was there someone that called it .ISO and everyone just copied it?
Ben
Posted 2013-04-22T09:54:45.023
Reputation: 1
Why is a .ISO called a .ISO?
Answers
Mathieu Westphal
Posted 2013-04-22T09:54:45.023
Reputation: 669
2Thanks its all clear now! It was me failing for not searching it up on Wikipedia. – Ben – 2013-04-22T10:04:10.663
2The people that coined this term must admit that it does not contain much information. ".966" would have been much more meaningful. – Raúl Salinas-Monteagudo – 2013-04-23T21:37:12.490
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The origin is the ISO 9660 file system which is used on CD-ROM. The extension .iso remained also for DVDs and Blu-Rays which use the UDF (ISO/IEC 13346) file system. See here for details.
Simon
Posted 2013-04-22T09:54:45.023
Reputation: 3 831
22+1 for mentioning that it does not necessarily contain an image with the ISO 9660 file system. – robingrindrod – 2013-04-22T12:38:14.757
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The name is derivated from a norm issued by the International Organization for Standardization which specifies the file system on an optical medium [1]. That norm has the abbreviation ISO 9660 [2] and you can guess now why a CD-ROM image (and later on a DVD-ROM image) usually is named .iso.
[1] http://en.wikipedia.org/wiki/ISO_9660
[2] Some confusion can arise why ISO isn't an acronym of International Organization for Standardization. Quoting once again Wikipedia:
Recognizing that its initials would be different in different languages, the organization adopted ISO, based on the Greek word isos (ἴσος, meaning equal), as the universal short form of its name.
mpy
Posted 2013-04-22T09:54:45.023
Reputation: 20 866
2So why isn't the filetype .iofs or .ios? – Izkata – 2013-04-22T13:55:57.400
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@Izkata because the short name of the organization is ISO http://www.iso.org/iso/about/about#2012_aboutiso_iso_name-text-Anchor
– Evan Harper – 2013-04-22T14:02:16.380.iofs is ruled out at once due to DOS's 8.3 convention (also pointed out by @aldric), for the latterhave a look at http://en.wikipedia.org/wiki/International_Organization_for_Standardization why ISO isn't abbreviated as IOS. – mpy – 2013-04-22T14:03:40.620
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The .iso extension is an alternate or a shortened form of .iso9660 or .isoimg, which could stand for "ISO 9660-compliant disk image."
The original ISO 9660 standard appears to have been produced in 1988, when PCs were still using 8.3-character filenames (e.g. names could be only 8 characters long, and extensions only 3), so ISO was likely the first choice for shortening the extension to three characters.
Source: Wikipedia (.isoimg) and Wikipedia (.iso9660)
8I've never seen a file with a .isoimg extension, even on systems that support arbitrarily long extensions, the Wikipedia article you link to doesn't mention it, and a Google search doesn't show anything. Do you have a basis for .iso being short for .isoimg, as opposed to, say, the phrase "ISO image"? – Keith Thompson – 2013-04-23T00:16:28.857
4Note that there are thousands of ISO standards, in diverse categories. You'll often here, eg, of "ISO-9000", a standard for running a business. There are standards for paper, for paint, for railway engineering, etc. – Daniel R Hicks – 2013-04-22T11:17:53.567
35Soon there will be an ISO standard for how to ask and answer questions about the ISO standards. Better get ready! ;-) – Warren P – 2013-04-22T11:38:08.523
3And the three letter extension (.ISO) was used due to that being the standard for DOS/Windows systems many of which could not handle longer filenames or extensions. – adric – 2013-04-22T11:44:28.540
2Great question, considering how large the ISO standards body is, and how many standards they have, why did a CD format get named after it? – MarcusJ – 2013-04-22T13:08:03.357
Just as a trivia,
isois also Greek for "same" (or so I've heard) – CamelBlues – 2013-04-22T16:06:28.593Wanted to point out that some programs used different extensions such as CDR or IMG. But ISO seemed to become the standard eventually. – Zan Lynx – 2013-04-22T16:29:15.030
1@ZanLynx note that some CD images are not uncompressed bitwise-copies of an ISO-9660 or ISO-13346 file system; those should not use an .ISO extension. In your examples, CDR is just the MacOS name for ISO, but IMG could literally be anything (including a floppy disk image). – KutuluMike – 2013-04-22T17:36:07.897
what a question! :) – ruben – 2013-04-22T21:03:37.783
1This has really been bugging me: It's not a .ISO it's an .ISO! Right? – AnnanFay – 2013-04-22T21:42:26.580
2It's "an ISO", but "a dot-ISO". Whether the phrase begins with a vowel depends entirely on whether you pronounce the dot at the beginning. :p – neminem – 2013-04-22T22:20:04.713