1. CD-ROM :
CD-ROM is a metal disc embedded into a plastic protective housing. Each disc has to be mastered, this is the process for creating the CD and placing the data on it. CDs are WORM (Write Once, Read Many) media, this refers to the fact once they have been mastered, there is no way to change the data on them.
2. Magnetic Disks :
Magnetic Disks contain circular disk made of metal or plastic. Both side of disk is usually used for storing data. The disk is coated by magnetic oxide. The disk is divided into multiple concentric circles known as track and tracks are divided into sectors in which data are stored.
Here are differences between CD-ROM and Magnetic Disks:
|It is metal disc embedded into plastic.||It contains metal or plastic.|
|Sectors in CD-ROM are organized along a spiral.||Sectors in Magnetic disks are organized in concentric track.|
|It has CLV (Constant Linear Velocity).||It has CAV (Constant Angular Velocity).|
|Sectors in CD-ROM have same linear length.||Sectors in Magnetic disks have same angular length.|
|In CD-ROM, data is packed at its maximum density permitted.||In Magnetic disks, data is written less densely in the outer tracks.|
|It takes advantage of all storage space.||It doesn’t use up all storage available.|
|It has to change rotational speed when seeking.||It operates on constant speed, timing marks to delimit tracks.|
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