The recordable compact disc was created by the Philips company in 1988 but not sold commercially until 1991. It was originally dubbed the CD-WO, which stood for Compact Disc-Write Once, but the name was changed before it hit the market to CD-R, which stands for Compact Disc-Recordable.
Two types of recordable CDs are available today--the CD-R, which is recordable one time, and the CD-RW, which can be written to multiple times. CD-RWs are newer and did not hit the market until 1997. They are great for transporting data, as the data can be overwritten many times, CD-RWs are cost-efficient; one disc can be used hundreds of times.
Recordable compact discs can hold 74 minutes of music, 650 megabytes of data or up to 80 minutes of digital audio as well as 700 megabytes of data. CD-RWs are unique in that they can have their data erased, and the disc can then be used to write new data. A CD-R, however, has write-once capability only. Recordable CDs are made from polycarbonate and can last a long and be read by a CD player, unless heavily scratched.
Either type of CD is useful for data transfer, but CD-Rs are useful in storing digital audio because they can be read by audio players in cars and home stereos. Although flash drives have become popular, many people still find the CD a viable option to transport data between computers. CDs are also popular for use with digital audio; it is convenient to copy songs to a CD and listen to them in the car or on a portable audio device with a CD player.
Since CD-Rs are write-once, if there are mistakes made during writing, the CD becomes useless to the operator. Take care when handling CDs of any kind because they can be scratched easily. Since they cannot be erased, any CD-Rs that contain private information of a sensitive nature should be destroyed.