Writing CDs and DVDs
This document describes some of the ways to write CD/DVDs on the departmental Linux machines (running Scientific Linux 5).
Gnome
Under Gnome, the default desktop, put the CD or DVD in the drive and an icon will appear on the desktop. Double click on this, a window will open called CD/DVD Creator drag the files you want to write to the CD/DVD into this window. When you are finished select the button Write to Disc.
For further help refer to the Gnome help in the application.
You can also launch the k3b application (from the Gnome menus in Sount & Video which is a KDE CD writing tool but works very well under Gnome - and has many more options than the default CD/DVD Creator tool.
Refer to the notes on reading a CD/DVD for how to eject the CD/DVD.
FVWM or command line
Under FVWM or on the command line, you can access the CD/DVD Creator described above by running the command:
nautilus --no-desktop computer:/
this will open a graphical interface of the devices of your computer called computer from this select the icon representing your CD/DVD.
Or you can simply run k3b from a terminal window.
What about the writecd command
Our locally written writecd command still exists and still
works fine on the sl5 Linux machines, but probably isn't the first thing that
newer users would want to use (it is pretty much just a wrapper round calls to
mkisofs/mkhybrid and cdrecord, with MD5 checksums of the resulting image). It
is still a useful and quick tool for writing/verifying a small directory (or
existing .iso file) to CD.
If You want to know more about writecd please read the man
page!
Graphically Finding the files to copy to the CD/DVD
If you always use the command line you may experience some difficulties naviagating around a graphical file interface.
You can drag files from your home directory to the CD/DVDwindow by selecting Places from the menu of the window called computer and then selecting Home.
To get to Data or Scratch areas, select the icon named Filesystem in the computer window, and from there select data or scratch and navigate your way to your data. You may find the scratch folder is empty, if this is the case, go to a command line and access the scratch space you are interested in, this will cause the graphical scratch window to display that scratch space, then double click on the icon to get to the contents.
How long will it take to write the cd?
The write speeds of drives are not the only factor needed to estimate how long it will take to write the CD. Firstly you need to be aware that few CD writers actually write at their quoted top speed most of the time. Most will start much slower and only get to the top speed for a small portion of the last part of a disk. Also the write speed depends on the maximum speed that the blank can use (usually written on the blank).
Modern drives are sufficiently fast that these calculations can probably be ignored in most cases.
A similar rule applies to the read speed. Few (if any) drives actually read at the quoted speed for most of the disk surface.
Can I add more data to a CD-R?
In a limited sense yes. If the disk was written as a multisession disk (e.g. with writecd using the -multi option) then additional sessions can be written to an existing CD-R, but only if all sessions are marked as multisession.
That is you can't add more data to a CD-R if the old data was written without the multisession feature. Using multiple sessions is somewhat wasteful of the capacity (space is wasted for each new session), but this may still be more useful than having to burn a new CD-R to add a few files.
Does this work with CD-RWs?
Yes, although the only special support for CD-RW media is the ability to erase them, for example there is a blank option on writecd.
Where to I get blank CDs from?
For making backups or archives of your DAMTP files or other work-related CD/DVD writing, blank media can be obtained from your group secretary or Reception or the computer officers who should have small numbers.
If you need large numbers you should probably e-mail help@damtp.cam.ac.uk so we can ensure that we have enough.