QuickSpecs

ISO 9660 Compact Disk File System (CDFS)
The Tru64 UNIX implementation of CDFS is based on ISO 9660, a standard for a volume and file structure for the
interchange of information using CD-ROM. Tru64 UNIX CDFS is based on the following levels of ISO 9660:
Level 2 of Interchange
Level 1 of Implementation, which enables the user to mount single-volume CD-ROMs that are formatted in compliance
with ISO 9660 as a local file system
Listing and examination of files using standard UNIX utilities and programs
Reading of files and directories using the standard POSIX system interface
NFS export mounted ISO 9660 file systems
Support for the High Sierra Group extensions that provide compatibility with older-format CD-ROMs
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 eight levels)
File time stamps
Open Group Preliminary Specification (1991) CD-ROM Support Component (XCDR)
XCDR extensions allow users to examine selected ISO 9660 attributes through defined utilities and shared libraries. A
system administrator can substitute different file protections, owners, and file names for CD-ROM files.
CDFS supports the organization of multiple sessions on one CD-ROM volume. The maximum number of CDFS mounts is
512. Note that the contents of all sessions are available as one file system and are not separately available. Users can
access DVD disks using the CDFS file system.
DVD File System (DVDFS)
The Tru64 UNIX implementation of DVDFS is based on the ECMA 167 Universal Disk Format (UDF) specification Version
2.00.
DVDFS gives the administrator the ability to mount and read UDF formatted Digital Versatile Disks on a single node as well
as in a cluster.
File-on-File Mounting File System (FFM)
The File-on-File Mounting File System allows regular, character, or block-special files to be mounted over regular files and is
primarily used by the SVR4-compatible system calls fattach and fdetach of a STREAMS-based pipe (or FIFO).
File-Based Pipes
A file-based pipe implementation replaces the socket-based pipe implementation for improved performance.
/proc File System
The SVR4-compatible /proc file system for Tru64 UNIX allows running processes to be accessed and manipulated as files
by ordinary system calls: open, close, read, write, seek, and ioctl.
QuickSpecs
HP Tru64 UNIX Operating System Version V5.1B
File Systems
DA - 11939 U.S. QuickSpecs — Version 1 — 4/8/2004 Page 10