Example of Optical Storage Devices

The different optical media are CDs, DVDs, Blu-ray disks, etc.

Compact Disk

CD has a diameter of 12 cm. The track on the CD is spiral-shaped, with around 20,000 windings. We’ve already explored the notion of information storage within the substrate. It is affordable, portable, and has a storage capacity of approximately 700 Mb. A compact disk operates in such a way that when the disc is inserted in the disk tray of a CD player, the track of the disc is scanned by a low-intensity laser beam. By rotating the disc between 200 and 500 revolutions per minute, a consistent scanning pace is maintained.

It is classified into three ways.

• CD-ROM: Compact Disk Read Only Memory, on which the manufacturer has pre-stored data.
• CD-R: Compact Disk-R is recordable, the data within this is written only one time by the user but it is not rewritable.
• CD-RW: Compact Disk-RW is rewritable, the data can be modified multiple times i.e., this can be read, erased, and written again and again as well.

Digital Video Disk

DVD is also known as digital versatile disk. This is a different kind of optical disk that holds data and multimedia content. It is the second form of optical disc to be introduced, following the compact disk. Despite its appearance, it can hold 15 times the amount of data that a CD can. A DVD provides approximately 4.7 GB to 17 GB of storage space.

DVD is also classified into mainly three parts.

• DVD-ROM: DVD-Read Only Memory permits the manufacturer to store data/information within it at the time of disk manufacturing and does not allow the disk to be rewritten.
• DVD-R: DVD-Recordable data is available to the user in blank format, and the user can only store data in it once.
• DVD-RW: DVD-Rewritable provides users with the ability to read and write data many times.

Blu-ray Disk

It is regarded as the third generation of compact disk technology, following the launch of CDs and DVDs. It is the most recent optical storage medium for storing high-definition (HD) audio and video. It contains about 128 GB of storage space.

Unlike CDs and DVDs, which employ a red laser beam for read/write operations, blu-ray disks use a blue-violet laser with a wavelength of 405 nm. The tracks on the disk can be wounded more closely due to the shorter wavelength of the laser than the high wavelength beam utilized by CDs and DVDs. As a result, it has a large storage capacity and can hold more data than CDs and DVDs.

THe Optical memory is an electronic storage medium that uses a laser beam to store and retrieve digital (binary) data. In optical storage technology, a laser beam encodes digital data on an optical disc or laser disc in the form of tiny pits arranged in a spiral pattern on the surface of the disc. Digital Versatile Disk (DVD), Compact Disk (CD) and Blu-Ray Disk are the examples of optical storage device.