cdfs(4) Kernel Interfaces Manual cdfs(4)
NAME
cdfs - The Compact Disk-Read Only Memory File System (CDFS)
DESCRIPTION
The ISO 9660 standard describes volume and file structures for information exchange on a Compact Disk-Read Only Memory (CD-ROM) volume.
CDFS supports mounting, as another local file system type, CD-ROMs that comply to the standard. Once mounted, files and directories
recorded on the CD-ROM become accessible in a read-only manner through system calls and commands. Support of the standard is limited to
Interchange Level 2 with the exception of multiple volume semantics, which are supported. Refer to the international standard ISO
9660-1988 for additional information pertaining to the actual standard.
The CDFS behaves the same as any read-only file system, and additionally supports the following semantics: The CDFS can be exported by NFS
Users can mount other file system types (UFS, NFS, AdvFS) onto directories recorded on a CD-ROM volume CD-ROM volumes can be recorded in
ISO 9660-1988, Interchange level 2, or (for backward compatibility) High Sierra Group (HSG) format The data on a CD-ROM volume that is
recorded as part of a multiple volume set or consists of a single volume is made available when the volume is mounted File systems on a CD-
ROM volume can be accessed locally and remotely The CDFS can be organized on a CD-ROM volume in multiple sessions. The contents of all
sessions is available as one file system; individual sessions are not separately available.
The CDFS also supports CD-ROMs recorded using the Rock Ridge Interchange Protocol, Revision 1.09, August 1991. Rock Ridge specifies the
use of the extension fields that are defined by ISO-9660:1988, and it uses those extensions to provide the following information: File
owner, file group, file permissions Additional file types (symbolic links, device special files, named pipes) setuid, setgid, and sticky
bits Hard link counts POSIX file names (mixed case names, unstructured names, and longer names than ISO-9660:1988 allows) Deep directory
hierarchies (greater than 8 levels) File time stamps
Refer to the Rock Ridge specification for additional information about the extensions.
The CDFS also supports the XCDR extensions (X/Open Preliminary Specification (1991) CD-ROM Support Component). These XCDR extensions add
the following support: Users can examine selected ISO 9660 attributes through defined utilities and shared libraries A system administrator
can substitute different file protections, owners, and file names for files on a CD-ROM volume.
RELATED INFORMATION
mount(8), cddevsuppl(8), cdsuf(1), cd_getdevmap(3), cd_setdevmap(3), and cd_suf(3) delim off
cdfs(4)