Reburning a CD [was: Virus on Library cdrom?]

[Robert Tiess]

Beth DeGeer wrote:
> I did not think one could re-burn a CD.

Hi, Beth. If the CD in question is in fact a CD-R that was created, closed, but not write protected (something that must be specified upon ejection of a CD-R), theoretically anyone else with a CD writer drive could open that same CD back up, make any number of modifications to the disk, and close it again so that it would be readable in most CD-ROM drives.  If a CD-R can be placed in a CD writer drive and you can make it writable again (e.g. if "Make Writable" is an option), that CD-R is susceptible to modification.

A CD-R for public use should always be write protected by its creator, but since many people are new to CD-Rs they might not know to do that.  On the bright side, if a CD-R is not write protected, you or someone with a CD-R drive could also reopen the CD-R and then close it immediately by ejecting the CD and checking "write protect."  If your disc is a CD-R and a virus was written to it, write protection is irrelevant now: the disc was already compromised and should be discarded.

One way of telling a CD-R from a CD is a CD-R usually has a blueish/greenish tint to it on the part of the disc the computer reads (not on the label side). A standard CD-ROM (silver on the read side) is in fact read only and unable to be reopened/rewritten due to the way it's created, unlike CD-Rs, which rely on dye. Here's a link to a site that explains some more how CD-Rs and CDs work: http://www.howstuffworks.com/question287.htm

Hope that was helpful :-)

Robert
rjtiess at warwick.net