There are different types of Compact Disc, but they all are used to store digital information.
The term ROM means read-only memory that allows the computer to read the data, which is already stored on the computer, and it cannot be deleted or changed. It was more popular for distributing games and software for several consoles. Furthermore, any standard can be used to play CD ROM recordings.
- Recordable CD (CD-R)
The CD-R stands for recordable, which is also known as CD-WORM (Write Once, Read Many) or CW-WO (write-once). Philips and Sony jointly developed it. Usually, these types of CDs have 74 minutes of music storage available, but some CDs can store as much as 80 minutes of music. It includes an advantage that the information is written once and can be read multiple times. It also had a limitation that it was not properly compatible with all devices; therefore, it had no ability to read all devices.
When it is inserted into the player, the inbuilt laser rays read the data, which is recorded by the user on it. The music CD became popular with the Recordable CD because most music albums were released in this format.
The CD+R is not relevant with the CD-R, the R in CD stand for recordable. A group of companies developed the +R format. It was developed to increase the amount of storage available on a compact disc. The CD+R allows for around twice storage space as compared to standard CD-R.
- Rewriteable CD (CD-RW)
The CD-RW can be used to write data a number of times, erased and re-used, and also used as a normal CD-R. Usually, a rewritable CD can store up to 700 MB of data and can be written again as many as 1000 times. But rewriting the stored video and audio in it reduces the quality of data. On a CD, a CD burner melts the recording layer onto a CD by using its highest laser power. In CD-RW, the burner melts the data layer by using its medium level of laser power; new data can be added to the disk. A CD player will not change the recorded layer, and it uses the lowest amount of laser power to read a CD.
- Video CD (VCD)
Simply, it was a CD, including moving images and pictures. It had a capacity of 650MB/700MB and could store 74/80 minutes of data. It was mainly used for watching movies. Later it was replaced with the SVCD and DVD as an image’s quality on this was not too good.
The Mini CD is wide around 3 inches and can store 210 megabytes of data or a maximum of 24 minutes of music. Mini CD’s can be used with most CD players.
It was widely used for single song recordings but also used for advertising and business purposes.