This contains instructions on writing to the CD-R/CD-RW drive
on the PC in Room 110. The instructions are specific to writing
data to be read on UNIX as well as PC machines.
WARNING!!
Because the PC is a public machine, it can be left in any number
of odd configurations. The instructions below may not be complete,
if, for example, someone has unmounted the data disks or the network
drives, etc. The software also can have a somewhat confusing interface
and people have been known to accidentally delete their raw data files
on the data-taking computer. Finally, the PC software will not
automatically partition large data sets into smaller, CD-sized sets
if you have more than 650 MB of data.
For this reason we strongly recommend that you use the
UNIX CD-writing software,
since it is more stable, and does automatic partitioning of data sets.
Some background. CD-R stands for recordable CD media,
sometimes called "write-once" media. You can write on
these one time; they cannot be erased. They hold 650 MB and a
blank disk costs typically a dollar or two. Some recorders will
only write one "session," which means you cannot write
some data, then go back later and write some more. Our drives do
not have this limitation; they are "multisession"
devices. However, the drivers for recent Sun Ultras cannot
read multisession CDs! Be aware of this if you have an
Ultra 10 or more recent machine.
CD-RW stands for "Re-Writable," which means that
they can be erased and rewritten several times. These hold 650
MB, too, but cost $15-$25 each. These disks are not readable on
some types of CD drives, in particular current audio CD
players. However, most PC or UNIX CD players will read them
fine.
Below is a guide to writing multisession CD-R disks on our
PC, using the Easy CD Creator software shipped with the
drive.
- Copy the data onto the PC.
This is important, as errors can occur if a given session is
not written as one long data stream.
- Open "File Transfer (ftp)" and log on. Your
UNIX username
and login should work.
- Navigate the directory system until you find your data.
- Click on a folder (which is equivalent to a UNIX
subdirectory) and
drag it to the "CD-scratch (D:)" drive. This
is a scratch disk
on the PC set aside specifically for staging CD-R sessions.
- After all of the data has been transferred to the PC,
you can quit
"File Transfer (ftp)".
- Set up the CD characteristics.
- Open Easy CD Creator. You can cancel the wizard which
may pop up at the beginning.
- Select "File --> CD Layout Properties"
(the item "CD Layout Properties" under the
"File" menu). This will bring
up a dialog box with some tabbed entries.
- Type in a disk name under "Volume Label"
(which is under the "General" tab). The disk
name cannot have spaces. It can have lower case
letters, although the PC will show them as upper case.
- Select the "Data Settings" tab. Confirm that
"File system =" is set to
"ISO9660".
- Click on the "Properties" button to the
right of "ISO9660". Make sure that "Long
filenames" is selected; otherwise your file names
will be truncated to DOS-style names, and you don't want
that! be forewarned that there may be some truncation
anyway. For example if your UNIX file name has two periods
in it, the last one and any text following it will be
removed. Also make sure that "Mode 2 CDROM XA"
is selected. This allows you to write multiple
sessions. You do not need this if you are going to fill up
the disk this one time, and will never want to write to it
again, but on the other hand it doesn't hurt.
- Insert the CD-R disk.
Press the EJECT button on the CD-ROM writer to open the
drawer, then insert your disk and press the same button to
close the drawer.
- Import previous session.
If you have already written some data onto the disk at a
previous session, you should import it now. In the
"Disc" menu, select "Import
session". This will allow you to select the previous
session or sessions. If you are writing for the first time
on this CD-R disk, you can skip this step.
- Add new files.
Drag the files and/or folders you want to write to the disk
from the upper left part of the window to the lower left
part of the window. Note the bottom of the window. It shows
how much total space will be used and how much is still
available on the disk. If you are, for example, writing a
folder full of CCD images, the entire folder may use up more
than the 650 MB available on a single CD-R disk. In this
case you will have to split the files into two or more
parts, and write them to two or more CD-R disks.
- Create the CD.
In the "File" menu select "Create
CD". This gives the option of running a test first,
then burning the data into the CD, or testing only, or going
straight to burning the CD. Once you get experienced you can
skip the testing stage.
- Wait for writing to complete.
A full CD takes about 30 minutes to write. During this time
it is best to leave the PC alone; if the data stream to the
CD-R drive is interrupted you may corrupt the disk.
- Clean up.
Remove any files on the scratch disk you do not
need. You might want to check the disk on a UNIX machine
first, or on another CD drive on a PC to make sure it has
turned out the way you intended.
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Bob Goodrich
Last modified: 27 December 1999
