CD-writable (CD-R) media are an inexpensive way to back up as
much as 760MB of data, including applications, personal files,
and multimedia files. CD-rewritable (CD-RW) media are also very
common, and allow the user to write files to the media multiple
times.
Recently, the DVD equivalents of these media have become more
common and more affordable. They behave similarly to CDs, but
can store up to 4.7GB of information. DVDs, in general, cannot
be read by CD-ROM drives, though most DVD-ROM drives can read
CDs. Refer to the manufacturer of your drive for more
information regarding compatible formats.
Below, we discuss tools for both CDs and DVDs.
13.3.1. Using CD/DVD Creator
Nautilus has an integrated tool,
CD/DVD Creator, that allows you to
write to CDs and DVDs.
CD/DVD Creator allows you to drag
and drop files from a Nautilus
window to the CD/DVD Creator
interface. To access the CD/DVD
Creator feature in
Nautilus, insert a blank CD-R(W)
into your drive and the CD/DVD
Creator window automatically starts. You
can also open CD/DVD Creator from
a Nautilus window by selecting
Go => CD
Creator.
Figure 13-3. The CD/DVD Creator Interface
in Nautilus
Open a new Nautilus window and
select the files or directories you want to write to CD or
DVD, then drag the files and folders to the
CD/DVD Creator window.
When you are ready to write the files to your CD or DVD, click
the Write to CD button in the
CD/DVD Creator window. The
Write to Disk window opens. Select the
write speed, name the CD or DVD, and click the
Write button when finished.
Figure 13-4. The CD/DVD Creator Write
Dialog Box
By default, the CD or DVD should automatically eject from your
drive when it is finished. Since it is generally
recommended to periodically backup personal files,
CD/DVD Creator can help you do so
quickly.
13.3.2. Using CD-Rs and CD-RWs with Command Line Tools
There are two shell prompt applications used to write image to
CDs and DVDs: mkisofs and
cdrecord. These utilities have several
advanced options that are beyond the scope of this guide;
however, for basic image creation and writing, these tools
save some time over the graphical alternatives such as
CD/DVD Creator.
13.3.2.1. Using mkisofs
The mkisofs utility creates ISO9660 image
files that can be written to a CD or DVD. The images created
by mkisofs can include all types of
files. It is most useful for archival and file backup
purposes. For CDs, make sure that the total data to be
written is less than 760MB. For DVDs, make sure that it is
less than 4.7GB of data.
Suppose you wish to backup a directory called
/home/user/, but exclude the
subdirectory /home/user/junk/ because
it contains unnecessary files. You want to create an ISO
image called backup.iso and write it to
CD or DVD. Backing up your data as an ISO9660 image is
useful in that it can be read by both Red Hat Enterprise Linux and Windows
systems. This can be done with mkisofs by
running the following command:
The image is created in your current working directory. Table 13-1 explains each
command line option. For more information on using
mkisofs, refer to the additional
resources in
Section 13.4 Additional Resources.
You can now use the ISO image file with
cdrecord, the command line based CD
recording utility. For more information about using
cdrecord, refer to Section 13.3.2.2 Using cdrecord.
Option
Function
-o
Specifies an output file name of the ISO
image.
-J
Generates Joliet naming records; useful if the
CD is used in Windows environments.
-R
Generates Rock Ridge (RR) naming records to
preserve filename length and casing, especially for
UNIX/Linux environments.
-A
Sets an Application ID — a text string
that will be written into the volume header of the
image which can be useful to determine what
applications are on the CD.
-V
Sets a Volume ID — a name that is
assigned to it if the image is burned, and the disc
is mounted in Solaris and Windows
environments.
-v
Sets verbose execution, which is useful for
viewing the status of the image as it is being
made.
-x
Excludes any directory immediately following
this option; this option can be repeated (for
example, ... -x /home/joe/trash -x
/home/joe/delete ...).
Table 13-1. mkisofs Options
13.3.2.2. Using cdrecord
The cdrecord utility writes audio,
data, and mixed-mode (a combination
of audio, video, and/or data) CDs and DVDs using options to
configure several aspects of the write process, including
speed, device, and data settings.
To use cdrecord, you must first
establish the device address of your CD or DVD device by
running the following command as root at a shell
prompt:
cdrecord -scanbus
This command shows all CD and DVD devices on your computer.
It is important to remember the device address of the device
used to write your CD. The following is an example output
from running cdrecord -scanbus.
To write the backup file image created with
mkisofs in the previous section, switch
to the root user and type the following at a shell
prompt:
cdrecord -v -eject speed=4 dev=0,3,0 backup.iso
The command sets the write speed (4), the device address
(0,3,0), and sets write output
(verbose [-v]), which is useful for
tracking the status of the write process. The
-eject argument ejects the media
after the write process is complete. The same command can
also be used for burning ISO image files downloaded from the
Internet, such as Red Hat Enterprise Linux ISO images.
You can use cdrecord to blank CD-RW or DVD-RW
discs for reuse by typing the following:
