ref: e655f4b8bdd9da0c51bd4bece8a2ea2088e57236
dir: /sys/man/4/cdfs/
.TH CDFS 4 .SH NAME cdfs, cddb \- optical disc (CD, DVD, BD) track reader and writer file system .SH SYNOPSIS .B cdfs [ .B -d .I sddev ] [ .B -m .I mtpt ] .br .B "grep aux/cddb /mnt/cd/ctl | rc .br .B aux/cddb [ .B -DTt ] [ .B -s .I server ] [ .B -e .I dir ] .B query .I diskid .I ntracks .I track0id .I ... .SH DESCRIPTION .I Cdfs serves a one and a half level directory mounted at .I mtpt (default .BR /mnt/cd ) that provides access to the tracks on discs placed in the disc reader or writer named by .I sddev (default .BR /dev/sdD0 , see .IR sd (3)). Any MMC-compliant compact disc (CD), DVD, or Blu-ray disc (BD) drive should work. On DVDs and BDs, access to data tracks only is implemented. .PP The top level directory contains one file per disc track. The files are named .IR cNNN , where .I c is a type character .RB ( a for audio tracks and .B d for data tracks) and .I NNN is the track number. .PP If the device can write discs and contains a writable disc, the top-level directory also contains an empty directory .B wd and, for CDs only, an empty directory .BR wa . Files created in these directories appear in the top-level directory as new data or audio tracks, respectively, regardless of name. .PP At any time, any number of tracks may be open for reading or a single track may be open for writing. Writing a disc track is a quasi-real-time operation: the disc writer should be kept saturated with new data to avoid buffer underruns, but modern drives will be told to cope with underruns transparently. To ensure saturation, copying from a file system stored on local disk or memory is recommended. .PP To fixate a disc (close a recordable disc by writing its permanent table of contents), simply remove the .B wa or .B wd directory. The directory removed selects whether the disc is fixated as an audio or data disc; since each track carries its own type information, very few readers care which fixation type was used. Rewritable discs do not require fixation. .PP The top level directory also contains a .B ctl file, into which control messages may be echoed. The current control messages are: .TF \fLquickblank .TP .B format Format the rewritable disc (\c .B -RW or .BR -RE ) in the drive before initial use. .TP .B blank Blank the entire rewritable disc in the drive. .TP .B quickblank Blank only the table of contents on the rewritable disc in the drive. .\" .TP .\" .B closetracks .\" Close any open tracks on the current disc but do not finalize (fixate) the disc. .TP .B eject Eject the disc in the drive. .TP .B ingest Ingest a disc into the drive. .TP .B speed \fIkbps\fR Set the reading and writing speed to use, in units of 1,000-bytes-per-second. A value of .L best requests the optimal speed for the current drive and disc. CD .L 1x speed is 154; DVD .L 1x speed is 1350; BD .L 1x speed is 4608. Drives may round down the speed to one they support. To set reading and writing speeds separately, prefix the speeds with .B read or .BR write , as in .B speed .B write .B 8192 or .B speed .B read .B 16384 .B write .BR 8192. Note that most drives reset the reading and writing speed each time a new disc is inserted. .PD .PP Reading the .B ctl file yields information about the drive. If the drive contains an audio CD, the first line will be an .B aux/cddb command that can be run to query an internet CD database to get a table of contents. Subsequent lines contain the current and maximum reading and writing speeds. Additional lines may further describe the current disc. .PP .I Aux/cddb takes 5 optional arguments. The .B -s option makes .I aux/cddb use .I server for the query instead of .LR gnudb.org . The .B -D option causes the raw database response from the server to be dumped to standard output. The .B -t option causes the time of each track to be appended to the normal output. .B -T is like .B -t but prints a final line with the total time. The .B -e option will print rc commands using .IR audio/flacenc (1) to encode and tag audio tracks from the disc to output directory .IR dir . .SH EXAMPLES Backup to a BD-R disc: .br .ne 3 .IP .EX 9fs boot cdfs tar cf /mnt/cd/wd/x /n/boot .EE .br .ne 3 .PP Copy the audio tracks from a CD: .IP .EX cdfs -d /dev/sd05 mkdir /tmp/songs cp /mnt/cd/a* /tmp/songs .EE .PP Copy the tracks onto a blank CD inserted in the drive, and then fixate the disk as an audio CD. .IP .EX cp /tmp/songs/* /mnt/cd/wa rm /mnt/cd/wa .EE .SH SOURCE .B /sys/src/cmd/cdfs .SH SEE ALSO .IR sd (3), .I 9660srv (in .IR dossrv (4)), .IR mk9660 (8) .PD 0 .TF "\fLhttp://www.t10.org\fP" .TP .B http://www.t10.org optical disc interface standards .PD .SH BUGS Fixating a BD-R disc records only the first track in the disc's TOC. Any other tracks are still there and their data accessible via .IR sd (3). There's no need to fixate data discs, except to prevent adding new tracks. .PP Closing a just-written DVD-R track can take minutes while the drive burns the unused part of the track reservation (for the whole disc). Thus only a single DVD-R track can be written on a DVD-R disc; use other media if you need more than one track per disc. .PP There are too many combinations of optical media, each with unique quirks, approximately the cross-product of these tuples: (CD DVD- DVD+ BD), (single-layer dual-layer), (-ROM -R -RW). .PP Only MMC-compliant disc readers and writers are supported, but it would be easy to add support for early CD writers if desired.