Andy's Unix FAQ

Question:

Subject: Backup Computer

I’m trying to make an image from my computer over the network. I have Semitic Goust program b but so far I do not have luck to make the computer image over network. I need to create a set of ISO file and bum them to CD’s to use in future. .

Do you know any program or script to make this job under Linux, Unix?
Thanks.

Answer:

I think that unlike many people you already have grasped the idea that
creating a CD-ROM is a two stage process;
1. Create an ISO9660 image.
2. Burning the image onto CD-ROM

Under Linux these two stages are performed by the programs mkisofs(8) and cdrecord(1). You should not try to write CD-ROMS with dd - this will only result in unusable disks as the disk and filesystem header information will not be created.

For more details have a look at the Linux HOWTO on the subject;
http://www.tldp.org/HOWTO/CD-Writing-HOWTO.html

TIP:
When writing the image to CD-ROM ("cdrecord") make sure you're system is not doing anything else. If the data stream to the drive gets interrupted you'll likely end up with a corrupt disk.
If your CD writer is attached to the same IDE controller as your hard disk this point is especially applicable. In this case I would suggest going to some lengths to ensure quiescence - for instance killing 'cron' is probably a good idea.

Professional CD-writer systems use multiple SCSI controllers, usually with the writer on a separate bus to any hard disks. SCSI is superior at maintaining burst-mode transfer rates, and off-loads all I/O processing from the CPU - both important points in a time critical process such as CD burning.