Optical storage - computer architecture:

Optical storage, the distinctive Optical disc, stores information in deformities on the surface of a circular disc and reads this information by revealing the surface with a observing the reflection with laser diode. Optical disc storage is non-volatile storage. The deformities can be enduring (read only media), formed only one time (write once media) or reversible (recordable or read/write media). Following forms are now in common use:

• CD, CD-ROM, DVD, BD-ROM: Read only storage are  used for mass distribution of digital information ( video computer programs , Music)
• DVD-R, CD-R, DVD+R BD-R: Write once storage, it is used for off-line or tertiary storage
• CD-RW, DVD-RW, DVD-RAM, DVD+RW, BD-RE:, fast read storage, Slow write can be used for tertiary and off-line storage
• Ultra Density Optical stand for UDO is similar in capacity to BD-RE or BD-R and is, fast read storage, slow write and can be used for tertiary and off-line storage.

Magneto-optical disc storage is optical disc storage wherever the magnetic state on a ferromagnetic surface stores information. The information is read optically and written by combining optical methods and magnetic and. Magneto-optical disc storage is non-volatile storage, slow write, sequential access, fast read storage and can be used for tertiary and off-line storage.