Compact Disc or CD is a circular digital disk mainly used for data storage. It is an extension of Laser Disc.
It was first developed by two companies namely Sony and Philips. CD was initially developed for sound recordings and storage only.
Later on as technology evolved, a CD was enabled to store chunks of data in its disk. CD then came to be known as CD-ROM(Compact Disk-Read Only Memory). The data stored has the read operation only but not the write operation. The first ever CD audio player was made available publicly by Sony in Japan.
The physical features of a CD include:
- A standard Compact Disc is about 120 millimeters in diameter and 1.2 millimeters in terms of width.
- It is mostly made up of plastic and has a shiny metallic surface.
- It weighs upto 15 to 20 grams only.
- The storage capacity of a CD is upto 700 MiB(Mebibyte) which means audio quality of upto 80 minutes can run using a Compact Disc.
- CD-ROM – Compact Disc-Read Only Memory is a popular and standard optical disk used for reading data in computers.
- CD-R – Recordable Comapct Disc has write operation feature. It is made up of special dye which reflects different colours when light falls on it. The shelf life of CD-R is 20 to 100 years.
- RW-CD – ReWritable Compact Disc is a disk in which data can erased and rewritten again and again.
- VCD – Video Compact Disc enables one to see a moving images clearly on the screen.
- It is small in terms of size.
- It is portable.
- Faster data access.
- It is cheap to produce.
- It has smaller storage capacity.
- When used more, it may produce scratches.
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