A. As you know, CD-ROM is short for Compact Disk, Read Only Memory. Most people just call it a "CD." It has basically replaced the old vinyl albums in the music world and because it holds a lot (about 600MB or 450 floppy disks) of data it is a standard in the PC world now too. Music is stored digitally (a series of 1's and 0's) on the CD just like programs and data.
CD-R stand for Compact Disk-Recordable. This means that not only can you use it like a regular CD player to play music, load programs, etc. but you can record your own stuff on blank disks that you can buy. You can even make copies of an existing music or software CD (be sure to honor any copyrights when you copy a CD.) The process of copying to a blank CD is called "burning" so when you hear someone say they will "burn a CD" it means they will copy items to a blank CD disk in their machine.
CD-RW is just like CD-R but the "RW" stand for Rewriteable. Using different blank CD disks, you can record onto these CDs just like with a CD-R but you can also re-record (or rewrite) onto the disk over and over again. Kind of like re-recording over an audiotape. The blank CD-RW disks cost a little more than the blank CD-R disks but may be worth it if you plan on reusing the disks.
DVD stands for Digital Versatile Disk. They are similar to CDs but hold a lot more data. A DVD can hold 4.7GB of information (4.7 billion characters) whereas the typical CD holds about 600MB or 600 million characters. So a DVD can store over 2 hours of video which makes it perfect for movies. Think of the CD as having the capacity to store about an album's worth of music while a DVD can hold an entire movie.
DVD-RW. Just as the CD's evolved to let you record your own music and data onto blank CDs, the DVD world is starting to catch up. Currently there are several competing standards for recordable DVDs and you may want to wait a while before you invest in one.
Answered by Tech Expert Dan Hanson