Universal Disk Format and ISO 9660 filesystem support
driver ... udf udf_options ... &
Where driver is one of the devb-* drivers, and
udf_options is one or more of the following, separated by commas:
- Control the case used to display ISO 9660 filenames (to a
request; all pathname matching is always performed case-insensitively on
- asis — don't convert the filename in any way;
if the CD was mastered with strict ISO 9660 compliance, the name will
be in uppercase, but more lenient utilities could produce mixed-case
- lower — convert to lowercase (the default).
- upper — convert to uppercase.
RRIP, Joliet, and ISO 9660:1999 store case-preserving names and ignore
|| If you specify both the case and charset options
for an ISO 9660 format, fs-udf.so ignores the
- Use a non-standard character set mapping for ISO 9660:1988 Primary
Volumes and ISO 96660:1999 Supplementary Volumes.
By default, these are ISO 646 (ASCII).
However a number of CD-burning tools incorrectly
use extended characters in filenames.
An appropriate charset= specification can allow these
filenames to be displayed according to a known alternate character set;
without such a hint, fs-udf.so replaces
with an underscore (_) any illegal characters in filenames.
Enhanced SVD format allows the active character set to be specified via
ISO 2022 escape sequences, but again many CD-burning utilities fail to
do this correctly, thus separate overrides are provided.
The supported character sets include:
The case in these strings doesn't matter.
- The File Set number to mount; the default is 0.
- Set both the list of disk formats to support, as well as the order in
which they should be probed (for media with multiple formats, such as
UDF-Bridge/DVD-Video or ISO/Joliet).
Separate the formats with colons (:)
You can use this option to:
- set a specific order in which to probe (e.g.
- remove a format (e.g. format=-rrip)
- add a format, making it the first preference (e.g.
The valid formats are:
- udf — OSTA/UDF, all v1.x and 2.x variants as supported.
- rrip — Rock Ridge extensions to ISO 9660;
adds permissions and long names.
- joliet — Joliet extensions to ISO 9660;
adds Unicode long names.
- iso9660e — the 1999 version of the ISO 9660 spec;
adds mixed-case filenames.
- iso9660 — the base 1988 version of the ISO 9660 spec.
- audio — create a dummy mountpoint for an
The first matching, valid format in order from the specified list is
|| Since the audio format matches any disk with audio
tracks, you should usually make it the last in the list.
In addition, since many formats are extensions to a base ISO 9660 format,
which is also present on the media, you should specify iso9660
itself after those formats.
The default is format=udf:rrip:joliet:iso9660e:iso9660:audio.
For backward compatibility, set the format to format=udf to
disable the CD/ISO formats.
- The group ID to use for files with no specified group.
The default is 0.
- Specify what to do with “hidden” files.
The hidden_mode can be one of:
- ignore — ignore the hidden files; they don't appear
in the filesystem.
- show — (the default) show hidden files in the
filesystem as normal files.
- dot — show hidden files in the filesystem with a dot
(.) prefixed to their names.
- The name of the filesystem metadata directory.
The first character can be + or -, and this controls
whether empty entries (metadata descriptors not given a value) are shown
in the directory or not, respectively.
For example, if a CD doesn't have a abstract or bibliography, those
pseudo-files can be hidden, or left with a empty string in them.
The default is -.info..
- The permissions to use for ISO 9660 files, directories, or both.
The argument to this option consists of the permissions for files, followed
by a colon (:), and then the permissions for directories.
Either set of permissions is optional.
You can specify the permissions either as a simple numeric value, or in
For example, to make files executable, specify perms=+x,
which is the equivalent to the exe option to
Like the uid and gid options, this option
is used only when the filesystem itself doesn't have explicit
permissions (udf and rrip do; all others don't).
The default is a=r:a=rx.
- Set the number of raw CDDA/CDXA 2352-byte buffers and optionally
the number of blocks to read with one raw I/O operation.
The default is 0:16 (raw read presentation as described below
If you specify only num (e.g. raw=2 vs
raw=2:8), then the chunk size remains 16.
The size of your raw buffer is the product of these two numbers and 2352.
Reading more sectors per operation improves the overall read performance.
When enabled, this option supports the transparent reading of
Mode 2 Form 2 VCD and audio files:
- For Mode 2 Form 2 VCD files, a 44-byte RIFF header is
constructed and prepended to the file data, and then data from
the files' raw 2352-byte sectors are supplied.
- Any audio tracks also get a filename in
which when read yields a similar RIFF header (but WAVE instead of CDXA
format), followed by the raw ripped audio.
If this option is disabled, such files are unreadable to POSIX
and fail with EINVAL.
You can use the
command to identify Mode 2 Form 2 or CDDA files.
- The user ID to use for files with no specified owner.
The default is 0 (root).
- How much of the ISO PVD or
UDF tag content (tag version, tag location, header
checksum, and/or data CRC) to verify; one of the following:
- tag — all except the data CRC
- ?all (the default)
Some ISO 9660:1999 SVD-mastering utilities and
UDF-authoring utilities write incorrect tags,
so it might be necessary to relax the verification if problems are observed.
If you specify an option with a leading question mark (?),
fs-udf.so consults an internal blacklist of
known bad utilities and automatically skips all checks in the list;
otherwise it operates at the level given after the question mark.
- The Primary Volume number to mount; the default is 0.
In addition, you can specify any of the
The fs-udf.so shared object provides support for
UDF (OSTA-UDF/ECMA-167) and ISO 9660 (base 1988 spec, 1999 spec,
Joliet extensions, Rock Ridge extensions) filesystems.
It's automatically loaded by the devb-*
drivers when mounting a UDF filesystem.
||This filesystem uses UTF-8 encoding for presentation of its filenames;
attempts to specify a filename not using UTF-8 encoding will fail
(with an error of EILSEQ).|
chapter of System Architecture
in the Working With Filesystems chapter,
“Filesystems and block I/O (devb-*) drivers”
in the Fine-Tuning Your System chapter, and
in the Understanding System Limits chapter
of the QNX Neutrino User's Guide
QNX Neutrino User's Guide: