Linux offers a host of CD/DVD writing and authoring
utilities. The entire field is evolving rapidly, and CD/DVD standards
are in a chaotic state. There are several competing, incompatible
standards, and more are looming on the horizon as commercial
distributors toil to develop a magical disc that will permit playback
but not copying. This chapter sidesteps all of this drama and
introduces some basic techniques for writing data CDs and DVDs.
You'll need the cdrtools and
To create discs the easy way, use
K3b. It is a graphical
frontend to cdrtools,
growisofs, and other command-line editing tools.
K3b makes it easy to set up your drives and to give users any
necessary root privileges, such as those required by
cdrecord and cdrdao. The
layout is logical and simple to use; it gets my vote as the best
CD/DVD writer on any platform. Of course, the Linux world offers many
more choices, such as GCombust, X-CD-Roast, and Gnome Toaster. These
are all simple to use, so this chapter will cover the command-line
tools. Understanding these will also make the graphical tools more
useful, as you'll understand the commands and weird
A major change in the
kernel is that you no longer need to use SCSI emulation for CD/DVD
drives. Instead of running cdrecord scanbus to
find the SCSI bus addresses, simply use the /dev
names of the devices:
# cdrecord dev=/dev/hdc <commands>
If you have upgraded
from a 2.4 to a 2.6 kernel and you used IDE-SCSI for your CD/DVD
drives, be sure that the IDE-SCSI entries are removed from your
bootloader, or you'll get strange boot errors.
11.1.1 Glossary of Formats and Standards
Here are the hardware standards:
CD-Recordable, or WORM (Write Once, Read Many). CD-Rs are universal
and should be readable in any CD-ROM drive.
CD-Rewritable, or WMRM (Write Many, Read Many). A drive must be
"multiread" to be able to read CD-R
and CD-RW discs. CD-RWs should be readable in all contemporary
Compact Disc-Read-Only Memory. Commercially produced discs are
pressed, not burned with a laser, and cannot be written to.
- Mount Rainier ReWrite
The circuitry needed by a drive to support UDF.
The standard used on commercially produced movie discs, playable on
all DVD machines.
- DVD-R and DVD+R
WORM format. Playable on all DVD players. DVD-R has two different,
incompatible disc types: DVD-R(A) and DVD-R(G). You
can't use A discs in G writers, and vice versa.
Rewritable, designed for data storage. Theoretically, it can take up
to 100,000 rewrites per disc. You can also record and play movies on
a PC, but a standalone DVD player probably won't be
able to read DVD-RAMs.
Designed for recording movies. This DVD standard is supported by the
DVD Forum (http://www.dvdforum.com).
A competing, incompatible standard to DVD-R/RW, supported by the
DVD+RW Alliance (http://www.dvdrw.com). Only DVD+R/RW supports
The newest generation of DVD drives for computers support all
formats. Standalone DVD recorders are still fighting standards wars
between the DVD+ and DVD- formats.
Here are the CD and DVD filesystem
- El Torito
Bootable format specification.
Universal Disk Format, the industry-standard incremental
packet-writing filesystem. This allows dropping files directly on to
a disc, just like on a 3.5" diskette. It was expected that Linux
would fully support this in the 2.6 kernel, but it's
not there yet.
The old file layout standard, allowing only 8.3 filenames (from the
ancient MS-DOS days, where filenames could have only up to 8 letters
and had to have 3-letter file extensions).
- Rock Ridge
Extensions to ISO-9660, allowing long filenames and Unix-style
symlinks. It preserves all file attributes, such as ownership and
permissions. Unix file attributes are not displayed when the disc is
read on a Windows system.
Microsoft extension to the ISO-9660 filesystem that allows Unicode
characters to be used in filenames, as well as long filenames. It
also creates truncated filenames for MS-DOS compatibility (these
weird-looking things: FILENA~1.TXT). It allows
filenames of up to 64 characters, including spaces, and is readable
by Windows 95 or later and by Macintosh computers running the Joliet
Volume Access extension. Macs will not read Joliet filenames that are
longer than 31 characters.
Here are the CD standards books:
- Yellow Book
Physical format for data CDs
- Orange Book
Physical format for recordable CDs, with multisession capability:
- Part I: CD-MO (Magneto-Optical)
- Part II: CD-R (Write-once; includes "hybrid" spec for PhotoCD)
- Part III: CD-RW (Re-writable)
- Red Book
CD Audio standard that describes the physical properties of the disc
and the digital audio encoding
These books can be purchased from
http://www.licensing.philips.com, if you really
want to get into the gory details.
These are the write options:
Any single recorded segment on a disc, which can contain data files
or a number of music tracks. A disc can contain several sessions.
The program area of a CD is divided into tracks; each track can
contain data of only one type. A disc (even a DVD) holds a maximim of
99 tracks—the number is hardcoded.
Allows adding files to a single disc over time, rather than having to
record all of your files in a single session. For a disc to be
readable, the session must be
"closed," or fixated. However, this
prevents adding more files to the disc. Multisession links the
individual sessions and updates the disc's table of
contents so that it appears as a single directory.
- SAO (session-at-once)
A single, complete session (lead-in, program, and lead-out areas) of
a CD-R or CD-RW disc, written in one uninterrupted sequence.
- DAO (disc-at-once)
Writes the entire CD in one pass, or session. The entire burn must
complete without interruption, and no more sessions may be added.
This is the most reliable way to record audio tracks.
- TAO (track-at-once)
Allows the writes to be done in multiple passes. There is a maximum
of 99 tracks per disc. Sometimes this causes audio CDs to not play
correctly on audio disc players, though I've found
it to be reliable.
For more information on DVDs, see the DVD FAQ at http://www.dvddemystified.com/dvdfaq.html.
For more information on CDs, see the CD Recordable FAQ at http://www.cdrfaq.org.