CD/DVD recorders and backup tape drives have been around for years now, but only with the advent of USB and FireWire have they become attractive to the PC power user as external devices. That's because in years past, hardware manufacturers had to depend on the PC's parallel port to connect these peripherals. The PC's parallel port was never designed for high-speed data transfer, so parallel port drives were slow.
However, today's FireWire and USB 2.0 drives are almost as blazing fast as their internal brethren! Therefore, as long as you have a USB or FireWire port, you have the option of sticking it in your machine or leaving it outside. It'll work like a charm either way.
Tape backup drives are beginning to disappear from the PC landscape because today's recordable DVD formats can hold 4.7GB (or 8.5GB for a dual-layer drive) on a single disc - and DVD recorders are faster and more reliable than most tape drives. Therefore, before you invest in a hideously expensive Digital Audio Tape (DAT) backup drive, consider buying a (comparatively) inexpensive rewriteable DVD drive instead and use that for your backups.
Types of CD/DVD recordable drives
Some CD and DVD drives are designed to not only read from the discs but also create them. The type of CD drive that can create CDs is called CD-R or, often, CD-R/RW. The letters R and RW represent the two recordable CD formats.
On the DVD side, the drive names get weird because there are many recordable DVD formats. The two most popular, however, are DVD-R and DVD+R. The DVD+R format is much faster than DVD-R, but not as compatible.
* The drive must say CD-R/RW or DVD-R or +R for it to be a recordable drive. Plain old CD and DVD drives cannot be used to create CDs or DVDs.
* You can get a combination CD/DVD drive that can record to both disk formats. It's often called the SuperDrive, though it's really just a combination CD-R/RW and DVD-R (or +R) drive. You can easily add an external USB version of the drive to your PC.
* Sony makes a versatile DVD drive that can record to multiple DVD formats. It can also record to CDs.
About the speed rating (the X number)
CDs have speed ratings measured in X. The number before the X indicates how much faster the drive is than the original PC CD-ROM drive (which plays as fast as a musical CD player). So, a 32X value means that it's 32 times faster than the original PC CD-ROM drive.
A recordable CD-R/RW drive has three Xs in its rating:
* The first is the drive's write speed, or how fast a CD-R can be written to.
* The second X is how fast the drive can rewrite to a CD-RW.
* The final X indicates how fast the drive can be read from.
High write and read speeds on a CD drive are especially important if you plan on importing lots of music discs. The higher the speed, the less time it takes the computer to read all the music from the drive.
Which drive is which?
Upon inspection, it's not exactly clear which disk drive could be the CD and which is the DVD. You have to look closely.
* CD drives usually have the CD logo on them. If it's a recordable drive, it also has the word Recordable and maybe even RW.
* DVD drives have the DVD logo on them. If you don't see the DVD logo, the drive is a CD-ROM drive.
http://tech.yahoo.com/gd/adding-a-recorder-or-tape-drive-to-your-pc/2469;_ylt=Au9_JR7aA2o97m6UD3F5jZcSLpA5
