It is becoming increasingly popular to run multimedia applications on PC systems with CD “burners”.  As a result, there are now many types of “blank” compact disk formats available.  The following explains the different formats:

CD-ROM:  This is the original CD disk that you can purchase in your local record or computer store.  It will contain pre-recorded information – music or software applications.  You cannot change the content of these disks other than play them or use them to install the software on your PC.

CD-R:  These blank disks, sometimes referred to as “write once, read only”, can be used to record information from your computer - data (computer files etc), or music (copied legally, of course).  Once recorded, they cannot be erased, and are therefore suitable for archiving information.  Capacity can be either 650Mb or 700Mb.

CD-RW:  This type is the same as the CD-R, but can subsequently be erased and re-recorded many times. 

DVD-R, DVD-RW, DVD+R, DVD+RW:  These four disk types are the latest in the line.  They are normally used to record video or albums of still images, since they can hold up to 4.7Gb of information. 

The “R” denotes that they can only be written to once, whereas “RW” that they can be written to, erased, and then re-recorded.  The “-“ and “+” symbols indicate two different formatting methods, each promoted by a separate group of manufacturers.  They are analogous to the VHS and BetaMax formats of video tape. 

It is difficult to predict which, if either of these formats will become a de facto standard.  It may not matter, since manufacturers are now beginning to produce DVD drives (for computers) that can read either standard.  Similarly, some of the latest stand-alone DVD players will also play either standard. 

Beware however, that many stand-alone players will not read any DVD disk produced on a computer.  If you need this facility, check with the documentation of the player before purchasing.  It is indeed a confusing business!