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Cd-R Cd-Rw Difference

You walk into a computer store. You’re looking to buy CDs and DVDs for recording… whatever. (We don’t judge your data storage habits at Helium.) You head to the disc racks at the side of the store… have a look at their selection…

And freeze. Each box seems to have something different printed on the side. CD-R? CD-RW? DVD-R? DVD-RW?! What does it all mean? This problem alone is often more than enough to drive wary newcomers away from the store and away from CD purchase altogether… which is a shame, since they’d get a really simple explanation to the different codes if they asked one of the attendants.

Functionally speaking CD-Rs and DVD-Rs are identical, if only in principle: they’re designed to store data. That data is written onto the discs in a series of microscopic pits, ringing the discs in long, spiraling circles. True, DVDs allow for more pits and thus more data, and require more precise lasers to read, but aside from that the basics of CDs and DVDs are the same. Once data is etched onto one that disc is bound to that fate forevermore.

Not so for CD-RWs and DVD-RWs. True, they are once again similar to one another, and to normal CDs and DVDs in that they allow for data storage, but with one major difference: you can rewrite onto them, over and over. The RW stands for ‘rewritable’. A rewritable disc can be wiped and filled with new info, if you wish, though the original data contained on the disc is lost.

Sounds like a great idea. Why aren’t RWs the standard, then? There are several reasons:

– Simply put, they cost more. You’ll have to pay more for a smaller package of RWs than you would for a package of Rs, regardless of whether you’re going for CDs or DVDs.

– They take longer to write. In order to render discs rewritable laser burning speeds are limited – and must also be kept at a certain minimum. This not only slows down the process, it increases the chances that something might go wrong, as the laser must be kept to very exact specifications to succeed. True, you can wipe the data and start again, but that’s a nuisance many don’t want to face.

– They aren’t perpetually rewritable. Think of a VHS tape. How many times could you copy over its contents before it started to wear down? Four, five, six times? RWs are the same way. You can’t keep wiping them and expect the same level of quality or data retention.

– Despite the wiping process, it IS possible to extract old info from RW discs, though you need extremely expensive equipment to do so. This may leave some companies looking to maintain their confidentiality a bit leery about using RWs.

– Last, most important, many disc drives don’t read RWs. It’s not a universal format like Rs, and thus it’s tough to tell if a particular drive will allow for the burning or reading of a particular RW disc. Why bother taking the chance that you’ll have to go back to the computer store and ask for a refund?

RWs have their uses, but for the most part you want to avoid these discs. They’re of limited use compared to various other media, and in the face of USB sticks that often carry a greater storage capacity with a whole lot less fuss RWs are slowly going the way of the dinosaur.