GetWiki
ISO 9660
ARTICLE SUBJECTS
being →
database →
ethics →
fiction →
history →
internet →
language →
linux →
logic →
method →
news →
policy →
purpose →
religion →
science →
software →
truth →
unix →
wiki →
ARTICLE TYPES
essay →
feed →
help →
system →
wiki →
ARTICLE ORIGINS
critical →
forked →
imported →
original →
ISO 9660
please note:
- the content below is remote from Wikipedia
- it has been imported raw for GetWiki
{{short description|File system for CD-R and CD-ROM optical discs}}{{Use dmy dates|date=July 2021}}- the content below is remote from Wikipedia
- it has been imported raw for GetWiki
factoids | |
---|---|
History
Compact discs were originally developed for recording musical data, but soon were used for storing additional digital data types because they were equally effective for archival mass data storage. Called CD-ROMs, the lowest level format for these type of compact discs was defined in the Yellow Book specification in 1983. However, this book did not define any format for organizing data on CD-ROMs into logical units such as files, which led to every CD-ROM maker creating its own format. In order to develop a CD-ROM file system standard (Z39.60 - Volume and File Structure of CDROM for Information Interchange), the National Information Standards Organization (NISO) set up Standards Committee SC EE (Compact Disc Data Format) in July 1985. In September/JOURNAL, Premium Reference Tool of the '90s, PC Magazine, 1986-10-14, 150â164, John, Helliwell,weblink 2016-11-18, October 1985 several companies invited experts to participate in the development of a working paper for such a standard.In November 1985, representatives of computer hardware manufacturers gathered at the High Sierra Hotel and Casino (currently called the Golden Nugget Lake Tahoe) in Stateline, Nevada.BOOK, Manes, Stephen, Stephen Manes, Andrews, Paul, 1993, Gates: How Microsoft's Mogul Reinvented an Industryâand Made Himself the Richest Man in America, Doubleday (publisher), Doubleday, 336, 0-385-42075-7, This group became known as the High Sierra Group (HSG). Present at the meeting were representatives from Apple Computer, AT&T,{{citation needed | date=August 2017}} Digital Equipment Corporation (DEC), Hitachi, LaserData, Microware,{{citation needed | date=August 2017}} Microsoft, 3M, Philips, Reference Technology Inc., Sony Corporation, TMS Inc., VideoTools (later MeridianJOURNAL, June 1987, The Future of CD-ROM,weblink Explorer, Atari Explorer Publications, 7, 19, 2016-11-18, Anderson, Gregg, 3, ), Xebec, and Yelick.{{citation needed | date=August 2017}} The meeting report evolved from the Yellow Book CD-ROM standard, which was so open ended it was leading to diversification and creation of many incompatible data storage methods. The High Sierra Group Proposal (HSGP) was released in May 1986, defining a file system for CD-ROMs commonly known as the High Sierra Format.A draft version of this proposal was submitted to the European Computer Manufacturers Association (ECMA) for standardization. With some changes, this led to the issue of the initial edition of the ECMA-119 standard in December 1986.WEB, Standard ECMA-119: Volume and File Structure of CDROM for Information Interchange, 1st, December 1986,weblink The ECMA submitted their standard to the International Standards Organization (ISO) for fast tracking, where it was further refined into the ISO 9660 standard. For compatibility the second edition of ECMA-119 was revised to be equivalent to ISO 9660 in December 1987.WEB, Standard ECMA-119: Volume and File Structure of CDROM for Information Interchange,weblink 2022-12-30, reprinted 2nd, September 1998, December 1987, BOOK, The Invention of Compact Discs,weblink WEB, Chip's CD Media Resource Center: CD-ROM page 6,weblink 24 November 2020, 26 July 2019,weblink" title="web.archive.org/web/20190726064954weblink">weblink dead, ISO 9660:1988 was published in 1988. The main changes from the High Sierra Format in the ECMA-119 and ISO 9660 standards were international extensions to allow the format to work better on non-US markets.In order not to create incompatibilities, NISO suspended further work on Z39.60, which had been adopted by NISO members on 28 May 1987. It was withdrawn before final approval, in favour of ISO 9660.JOURNAL, Peters, Paul Evan, Paul Evan Peters, CD-ROM Standards: The Fate of Z39.60, Information Standards Quarterly, National Information Standards Organization (NISO), July 1989, 1, 3, 1â3, 1041-0031,weblink 2016-11-18, live,weblink" title="web.archive.org/web/20161118095423weblink">weblink 2016-11-18, JIS X 0606:1998 was passed in Japan in 1998 with much-relaxed file name rules using a new "enhanced volume descriptor" data structure. The standard was submitted for ISO 9660:1999 and supposedly fast-tracked, but nothing came out of it.WEB,weblink JIS X 0606:1998 / ISO 9660:1999 Draft Specification, Nevertheless, several operating systems and disc authoring tools (such as Nero Burning ROM, mkisofs and ImgBurn) now support the addition, under such names as "ISO 9660:1999", "ISO 9660 v2", or "ISO 9660 Level 4". In 2013, the proposal was finally formalized in the form of ISO 9660/Amendment 1, intended to "bring harmonization between ISO 9660 and widely used 'Joliet Specification'."ISO 9660, Amendment 1 (ISO 9660:1988/Amd.1:2013(E)) In December 2017, a 3rd Edition of ECMA-119 was published that is technically identical with ISO 9660, Amendment 1.WEB, Standard ECMA-119,weblink Ecma International, Ecma, 16 August 2018, vii, In 2019, ECMA published a 4th version of ECMA-119, integrating the Joliet text as "Annex C".In 2020, ISO published Amendment 2, which adds some minor clarifying matter, but does not add or correct any technical information of the standard.ISO 9660, Amendment 2 (ISO 9660:1988/Amd.2:2020(E))Specifications
The following is the rough overall structure of the ISO 9660 file system.Multi-byte values can be stored in three different formats: little-endian, big-endian, and in a concatenation of both types in what the specification calls "both-byte" order. Both-byte order is required in several fields in the volume descriptors and directory records, while path tables can be either little-endian or big-endian.Top level
{| class="wikitable"|+ ISO 9660 file systemVolume descriptor set
The data area begins with the volume descriptor set, a set of one or more volume descriptors terminated with a volume descriptor set terminator. These collectively act as a header for the data area, describing its content (similar to the BIOS parameter block used by FAT, HPFS and NTFS formatted disks).{| class="wikitable"|+ Volume descriptor set- Supplementary volume descriptors describe the same volume as the primary volume descriptor does, and are normally used for providing additional code page support when the standard code tables are insufficient. The standard specifies that ISO 2022 is used for managing code sets that are wider than 8 bytes, and that ISO 2375 escape sequences are used to identify each particular code page used. Consequently, ISO 9660 supports international single-byte and multi-byte character sets, provided they fit into the framework of the referenced standards. However, ISO 9660 does not specify any code pages that are guaranteed to be supported: all use of code tables other than those defined in the standard itself are subject to agreement between the originator and the recipient of the volume.
- Enhanced volume descriptors were introduced in ISO 9660, Amendment 1. They relax some of the requirements of the other volume descriptors and the directory records referenced by them: for example, the directory depth can exceed eight, file identifiers need not contain '.' or file version number, the length of a file and directory identifier is maximized to 207.
Path tables
Path tables summarize the directory structure of the relevant directory hierarchy. For each directory in the image, the path table provides the directory identifier, the location of the extent in which the directory is recorded, the length of any extended attributes associated with the directory, and the index of its parent directory path table entry. The parent directory number is a 16-bit number, limiting its range from 1 to 65,535.ISO9660 sections 6.9 and 9.4.4Directories and files
(File:Iso9660directoryTree.png|thumb|Overview of the ISO 9660 directory structure)Directory entries are stored following the location of the root directory entry, where evaluation of filenames is begun. Both directories and files are stored as extents, which are sequential series of sectors. Files and directories are differentiated only by a file attribute that indicates its nature (similar to Unix). The attributes of a file are stored in the directory entry that describes the file, and optionally in the extended attribute record. To locate a file, the directory names in the file's path can be checked sequentially, going to the location of each directory to obtain the location of the subsequent subdirectory. However, a file can also be located through the path table provided by the file system. This path table stores information about each directory, its parent, and its location on disc. Since the path table is stored in a contiguous region, it can be searched much faster than jumping to the particular locations of each directory in the file's path, thus reducing seek time.The standard specifies three nested levels of interchange (paraphrased from section 10):- Level 1: File names are limited to eight characters with a three-character extension. Directory names are limited to eight characters. Files may contain one single file section.
- Level 2: Files may contain one single file section.
- Level 3: No additional restrictions than those stipulated in the main body of the standard. That is, directory identifiers may not exceed 31 characters in length, and file name + '.' + file name extension may not exceed 30 characters in length (sections 7.5 and 7.6). Files are also allowed to consist of multiple non-contiguous sections (with some restrictions as to order).
- All levels restrict file names in the mandatory file hierarchy to upper case letters, digits, underscores ("_"), and a dot. (See also section 7.4.4 and Annex A.)
- If no characters are specified for the File Name then the File Name Extension shall consist of at least one character.
- If no characters are specified for the File Name Extension then the File Name shall consist of at least one character.
- File names shall not have more than one dot.
- Directory names shall not use dots at all.
Extensions and improvements
There are several extensions to ISO 9660 that relax some of its limitations. Notable examples include Rock Ridge (Unix-style permissions and longer names), Joliet (Unicode, allowing non-Latin scripts to be used), El Torito (enables CDs to be bootable) and the Apple ISO 9660 Extensions (file characteristics specific to the classic Mac OS and macOS, such as resource forks, file backup date and more).SUSP
System Use Sharing Protocol (SUSP, IEEE P1281) provides a generic way of including additional properties for any directory entry reachable from the primary volume descriptor (PVD). In an ISO 9660 volume, every directory entry has an optional system use area whose contents are undefined and left to be interpreted by the system. SUSP defines a method to subdivide that area into multiple system use fields, each identified by a two-character signature tag. The idea behind SUSP was that it would enable any number of independent extensions to ISO 9660 to be created and included on a volume without conflicting. It also allows for the inclusion of property data that would otherwise be too large to fit within the limits of the system use area.SUSP defines several common tags and system use fields:- CE: Continuation area
- PD: Padding field
- SP: System use sharing protocol indicator
- ST: System use sharing protocol terminator
- ER: Extensions reference
- ES: Extension selector
- AA: Apple extension, preferred
- BA: Apple extension, old (length attribute is missing)
- AS: Amiga file properties
- ZF: zisofs compressed file, usually produced by program mkzftree or by libisofs. Transparently decompressed by Linux kernel if built with CONFIG_ZISOFS.WEB, linux/fs/isofs/Kconfig, GitHub, 23 January 2022,weblink
- AL: records Extended File Attributes, including ACLs. Proposed by libburnia, supported by libisofs.WEB, Arbitrary Attribute Interchange Protocol,weblink
Rock Ridge
The Rock Ridge Interchange Protocol (RRIP, IEEE P1282) is an extension which adds POSIX file system semantics. The availability of these extension properties allows for better integration with Unix and Unix-like operating systems.WEB,weblink RRIP (IEEE P1282) Draft Standard 1.12, 8 July 1994,weblink" title="web.archive.org/web/20170404043745weblink">weblink 2017-04-04, dead, The standard takes its name from the fictional town Rock Ridge in Mel Brooks' film Blazing Saddles.WEB, CDFS The Rock Ridge Interchange Protocol (RRIP, IEEE P1282),weblink The RRIP extensions are, briefly:- Longer file names (up to 255 bytes) and fewer restrictions on allowed characters (support for lowercase, etc.)
- UNIX-style file modes, user ids and group ids, and file timestamps
- Support for Symbolic links and device files
- Deeper directory hierarchy (more than 8 levels)
- Efficient storage of sparse files
- RR: Rock Ridge extensions in-use indicator (note: dropped from standard after version 1.09)
- PX: POSIX file attributes
- PN: POSIX device numbers
- SL: symbolic link
- NM: alternate name
- CL: child link
- PL: parent link
- RE: relocated directory
- TF: time stamp
- SF: sparse file data
El Torito
{{missing information|section|relationship to FAT filesystem, operation under UEFI|date=September 2023}}El Torito is an extension designed to allow booting a computer from a CD-ROM. It was announced in November 1994PRESS RELEASE, Phoenix announces bootable CD-ROM specification; Specification developed jointly by Phoenix and IBM, Phoenix Technologies Ltd., 1994-11-11,weblink 2008-01-31, 10 August 2017,weblink dead, and first issued in January 1995 as a joint proposal by IBM and BIOS manufacturer Phoenix Technologies. According to legend, the El Torito CD/DVD extension to ISO 9660 got its name because its design originated in an El Torito restaurant in Irvine, California ({{CoordDec|33.684722|-117.852547}}). The initial two authors were Curtis Stevens, of Phoenix Technologies, and Stan Merkin, of IBM.A 32-bit PC BIOS will search for boot code on an ISO 9660 CD-ROM. The standard allows for booting in two different modes. Either in hard disk emulation when the boot information can be accessed directly from the CD media, or in floppy emulation mode where the boot information is stored in an image file of a floppy disk, which is loaded from the CD and then behaves as a virtual floppy disk. This is useful for computers that were designed to boot only from a floppy drive. For modern computers the "no emulation" mode is generally the more reliable method. The BIOS will assign a BIOS drive number to the CD drive. The drive number (for INT 13H) assigned is any of 80hex (hard disk emulation), 00hex (floppy disk emulation) or an arbitrary number if the BIOS should not provide emulation. Emulation is useful for booting older operating systems from a CD, by making it appear to them as if they were booted from a hard or floppy disk.El Torito can also be used to produce CDs which can boot up Linux operating systems, by including the GRUB bootloader on the CD and following the Multiboot Specification. While the El Torito spec alludes to a "Mac" platform ID, PowerPC-based Apple Macintosh computers don't use it.WEB,weblink Bootable hybrid (ISO/HFS) CD-ROMs, 2014-01-03,Joliet
Joliet is an extension specified and endorsed by Microsoft and has been supported by all versions of its Windows operating system since Windows 95WEB, Joliet Specification for CD-ROM, MSKB 125630, Microsoft Knowledge Base, Microsoft, 2005-07-11,weblink 2012-05-29, and Windows NT 4.0.WEB, Windows NT Support For Long File Names Under CDFS File System, MSKB 142372, Microsoft Knowledge Base, Microsoft, 1 November 2006,weblink 2012-05-29, Its primary focus is the relaxation of the filename restrictions inherent with full ISO 9660 compliance. Joliet accomplishes this by supplying an additional set of filenames that are encoded in UCS-2BE (UTF-16BE in practice since Windows 2000). These filenames are stored in a special supplementary volume descriptor, that is safely ignored by ISO 9660-compliant software, thus preserving backward compatibility. The specification only allows filenames to be up to 64 Unicode characters in length. However, the documentation for mkisofs states filenames up to 103 characters in length do not appear to cause problems.{{man|8|mkisofs|FreeBSD}} Microsoft has documented it "can use up to 110 characters."WEB, 5 Appendix A: Product Behavior,weblink 13 April 2014, The difference lies in whether CDXA extension space is used.Joliet allows Unicode characters to be used for all text fields, which includes file names and the volume name. A "Secondary" volume descriptor with type 2 contains the same information as the Primary one (sector 16 offset 40 bytes), but in UCS-2BE in sector 17, offset 40 bytes. As a result of this, the volume name is limited to 16 characters.Many current PC operating systems are able to read Joliet-formatted media, thus allowing exchange of files between those operating systems even if non-Roman characters are involved (such as Arabic, Japanese or Cyrillic), which was formerly not possible with plain ISO 9660-formatted media. Operating systems which can read Joliet media include:- Microsoft Windows; Microsoft recommends the use of the Joliet extension for developers targeting Windows.
- LinuxWEB, Is Microsoft's Joliet filesystem supported?, The Linux CD-ROM HOWTO, Revision 1.17, 18 July 2001, Jeff Tranter,weblink 2012-05-29,
- macOSWEB, hdiutil(1), BSD General Commands Manual, Apple, 18 March 2011, Mac OS X Version 10.7.4,weblink 2012-05-29,
- FreeBSDWEB, FreeBSD 3.2 Release Notes, The FreeBSD Project,weblink 29 May 2012,
- OpenSolarisWEB, hsfs - High Sierra & ISO 9660 CD-ROM file system, OpenSolaris Man Page Set, 1 November 2006, SunOS 5.11 / OpenSolaris 2009.06,weblink 2012-05-29,
- HaikuWEB, Haiku Source Tree, src/add-ons/kernel/file_systems/iso9660/iso9660.cpp,weblink
- AmigaOS
- RISC OSWEB, Add support for Joliet format CD-ROMs hdr/Hashes s/Directory s/EntryFile s/FileMan s/Filer s/Free (999bdda6) · Commits · RiscOS / Sources / FileSys / CDFS / CDFS, 15 August 2013,weblink
Romeo
Romeo was developed by Adaptec and allows the use of long filenames up to 128 characters, written directly into the primary volume descriptor using the current code page. This format is built around the workings of Windows 9x and Windows NT "CDFS" drivers.WEB,weblink CD-ROM Discs: Joliet & Romeo Name Definitions, Apple Inc., 1 June 2007, 2010-07-20, When a Windows installation of a different language opens a Romeo disk, the lack of code page indication will cause non-ASCII characters in file names to become Mojibake. For example, "ü" may become "³". A different OS may encounter a similar problem or refuse to recognize these noncompliant names outright.The same code page problem technically exists in standard ISO 9660, which allows open interpretation of the supplemental and enhanced volume descriptors to any character encoding subject to agreement. However, the primary volume descriptor is guaranteed to be a small subset of ASCII.Apple extensions
Apple Computer authored a set of extensions that add ProDOS or HFS/HFS+ (the primary contemporary file systems for the classic Mac OS) properties to the filesystem. Some of the additional metadata properties include:WEB,weblink Technical Note FL36: Apple Extensions to ISO 9660,weblink" title="web.archive.org/web/20081226015418weblink">weblink 26 December 2008, dead,- Date of last backup
- File type
- Creator code
- Flags and data for display
- Reference to a resource fork
Other extensions
For operating systems which do not support any extensions, a name translation file TRANS.TBL must be used. The TRANS.TBL file is a plain ASCII text file. Each line contains three fields, separated by an arbitrary amount of whitespace:- The file type ("F" for file or "D" for directory);
- The ISO 9660 filename (including the usually hidden ";1" for files); and
- The extended filename, which may contain spaces.
Disc images
Optical disc images are a common way to electronically transfer the contents of CD-ROMs. They often have the filename extension .iso (.iso9660 is less common, but also in use) and are commonly referred to as "ISOs".WEB, Gavin, Brady, What Is An ISO File (And How Do I Use Them)?,weblink 2021-12-23, How-To Geek, 25 June 2018, en-US,Platforms
Most operating systems support reading of ISO 9660 formatted discs, and most new versions support the extensions such as Rock Ridge and Joliet. Operating systems that do not support the extensions usually show the basic (non-extended) features of a plain ISO 9660 disc.Operating systems that support ISO 9660 and its extensions include the following:- DOS: access with extensions, such as MSCDEX.EXE (Microsoft CDROM Extension), NWCDEX.EXE or CORELCDX.EXE
- Microsoft Windows 95, Windows 98, Windows ME: can read ISO 9660 Level 1, 2, 3, and Joliet
- Microsoft Windows NT 4.0, Windows 2000, Windows XP, and newer Windows versions, can read ISO 9660 Level 1, 2, 3, Joliet, and ISO 9660:1999. Windows 7 may also mistake UDF format for CDFS. for more information see UDF.
- Linux and BSD: ISO 9660 Level 1, 2, 3, Joliet, Rock Ridge, and ISO 9660:1999
- Apple GS/OS: ISO Level 1 and 2 support via the HS.FST File System Translator.WEB,weblink The Virtual GS: Using ISO disk images in Apple II emulators, Juiced.GS Volume 9, Issue 2, May 2004,
- Classic Mac OS 7 to 9: ISO Level 1, 2. Optional free software supports Rock Ridge and Joliet (including ISO Level 3): Joke Ridge and Joliet Volume Access.
- macOS (all versions): ISO Level 1, 2, Joliet and Rock Ridge Extensions. Level 3 is not currently supported, although users have been able to mount these discsWEB,weblink Work with PC-created Joliet Level 3 CDs, 16 April 2004,
- AmigaOS supports the "AS" extensions (which preserve the Amiga protection bits and file comments)
- QNX
- ULTRIX
- OS/2, eComStation and ArcaOS
- BeOS, Zeta and Haiku
- OpenVMS supports only ISO 9660 Interchange levels 1â3, with no extensionsWEB, Hoffman Labs, The OpenVMS Frequently Asked Questions (FAQs),weblink 1 September 2011, 19 November 2017,weblink" title="web.archive.org/web/20171119173826weblink">weblink dead,
- RISC OS support for optical media written on a PC is patchy. Most CD-Rs/RWs work perfectly, however DVD+-Rs/RWs/RAMs are entirely hit and miss running RISC OS 4.02, RISC OS 4.39 and RISC OS 6.20{{Citation needed|date=December 2017}}
See also
- Comparison of disc image software
- Disk image emulator
- List of ISO standards
- Hybrid CD
- ISO/IEC JTC 1/SC 23
References
{{reflist}}Further reading
External links
- WEB,weblink ISO 9660,
- WEB,weblink ECMA-119, This is the ECMA release of the ISO 9660:1988 standard, available as a free download
- WEB,weblink dead,weblink" title="web.archive.org/web/20220527031632weblink">weblink 27 May 2022, Summary of the ISO 9660 Specifications,
- WEB,weblink Description of data structures in ISO-9660,weblink" title="web.archive.org/web/20110717142714weblink">weblink 17 July 2011,
- {{Freshmeat|iat|ISO 9660 Analyzer Tool (iat)}}
- WEB,weblink RRIP History: About Young Minds, Inc.,weblink" title="web.archive.org/web/20180317214944weblink">weblink 17 March 2018,
- WEB,weblink SUSP (IEEE P1281) Draft Standard 1.12, 8 July 1994,weblink" title="web.archive.org/web/20170404132301weblink">weblink 2017-04-04, dead,
- WEB,weblink RRIP (IEEE P1282) Draft Standard 1.12, 8 July 1994,weblink" title="web.archive.org/web/20170404043745weblink">weblink 2017-04-04, dead,
- WEB,weblink Amiga Extensions on Rock Ridge: "Documents related to MakeCD program", 5 December 1996,
- weblink" title="archive.today/20130415092739weblink">ISOLINUX source code (see isolinux.asm line 294 onward)
- WEB,weblink Ralf Brown's interrupt list, (see int 13h in interrupt.b, esp. functions 4a to 4d)
- WEB,weblink EL Torito Specification Supplement, , discusses shortcomings of the standard
- US Patent 5758352 - Common name space for long and short filenames
- WEB,weblink Joliet Specification,
- content above as imported from Wikipedia
- "ISO 9660" does not exist on GetWiki (yet)
- time: 12:34am EDT - Sat, May 18 2024
- "ISO 9660" does not exist on GetWiki (yet)
- time: 12:34am EDT - Sat, May 18 2024
[ this remote article is provided by Wikipedia ]
LATEST EDITS [ see all ]
GETWIKI 23 MAY 2022
The Illusion of Choice
Culture
Culture
GETWIKI 09 JUL 2019
Eastern Philosophy
History of Philosophy
History of Philosophy
GETWIKI 09 MAY 2016
GetMeta:About
GetWiki
GetWiki
GETWIKI 18 OCT 2015
M.R.M. Parrott
Biographies
Biographies
GETWIKI 20 AUG 2014
GetMeta:News
GetWiki
GetWiki
© 2024 M.R.M. PARROTT | ALL RIGHTS RESERVED