This tip was printed from the MalekTips Computer and Technology Help and Tips website at http://malektips.com.

CDs and DVDs - What is -R Versus -RW?

When you purchase CD-Rs or DVD-Rs, you are purchasing media that you can write to only once; you cannot erase information once it has been written to the CD or DVD. Depending on your CD software, you may be able to create multi-session CDs or DVDs where you can write to the CD or DVD once, not filling it up, then add more information to it later. However, previously written information cannot be erased.

With CD-RWs and DVD-RWs, however, provided that you have drives that support this media, you can erase information previously written to the media. You may not be able to erase and rewrite information an infinite number of times; however, it should be enough for most purposes.

To add to this confusion, there is a format called DVD-RAM that supposedly allows you to rewrite information many more times than on DVD-RWs. However, these are only compatible with a select number of drives. Plus, with DVDs there is DVD-R, DVD+R, DVD-RW, and DVD+RW, and you may not be able to use one particular DVD with a different unit that doesn't support the same standard.

Speaking of compatibility, generally -R media is more compatible that -RW and +RW media; for example, you may not be able to play a music CD written on -RW media on your home stereo. Also, -RW, +RW, and -RAM media may not last as long as -R media; thus, RW, +RW, and -RAM are usually used for temporary backups, working files, and the like.