ISO 9660
ISO 9660 is a read-only filesystem often used on CD-ROMs. It is also common to encounter files containing an image of an ISO 9660 filesystem.
Contents |
Details
The standard limits filenames to the DOS 8.3 style. Several extensions – TRANS.TBL, Rock Ridge, and Joliet – were developed to remove this restriction.
The filenames also have a VMS-style version number, so sometimes they are shown with a ";1" suffix.
The size of a file is limited to 4GB (2GB in some implementations). This is irrelevant with respect to CD-ROMs, because of their small capacity, but it is a reason to avoid using ISO 9660 on DVD-ROMs and other media. (An extension called "multiple extents" makes larger files possible, but support for it is limited.)
Identification
Usually, the ASCII string "CD001" appears at offset 32769.
The first 32768 bytes are not used. Be aware that hybrid filesystems are possible. Just because something is a valid ISO 9660 filesystem doesn't mean it can't also be a valid filesystem of some other type.
See also
Software
Reading
- 7-Zip, see here for an example
- isoinfo can perform basic operations and some validation.
Operating systems often include drivers for ISO 9660. On Linux, an ISO 9660 image file can be mounted using a loopback driver (mount -t iso9660 -o loop ...).
Writing
- cdrkit → genisoimage
- Countless CD burning applications
