On Thu, 2002-11-07 at 00:57, Omer Zak wrote: > 1. If you need to backup less than 650MB (compressed) a day, and you don't > need to destroy/recycle media, then CD-ROMs may be the best way. > 2. If you want to recycle media (to wipe out older information), you may > want to consider CD-R media.
Do yourself a big favor and don't. The act of reading information from a CDROM is a small miracle of engineering. The little "holes" on the CDROM that reflect the laser beam are actually smaller then the beam's "width" and hence for various reasons having to do with advanced physics there is a certain statistical chance for a misread built right into the very process of reading CDs. To overcome this, CDs contain a big amount of redundancy, which guarantees that the actual error levels will remain generally acceptable over time[1] for *normal usage*, but ever since I had the misfortune once to try to debug a problem that was caused by the fact that the very small percentage of actual read errors still gets to be very significant given high enough numbers of CDROM/reads when used in high scale production environment (and we're talking about factory burned CDs here, NOT CD-R!) I don't trust CDROMs for anything important since then. [1] Because of this you can theoretical drill a 1 cm hole on a used surface of a CD and still read the information - the information is recorded in several copies in several places on the CD. Theoretical, because drilling a hole in the CD will make it not balanced and then you won't be able to read it in normal equipment - but the data will still be there. Gilad. -- Gilad Ben-Yossef <[EMAIL PROTECTED]> http://benyossef.com "Denial really is a river in Eygept." ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
