Disc

Disc or Disk common medium for storing data(an alternative is magnetic tape)A magnetic disc is ratated at high speed in a disc drive unit as read the magnetic variations that encode tha data.Recently optical dises such as CD-ROM(compact-disk read only memmory)CD-R(Recordable compact discs),and worm (write once read many times)have been used to store computer data
Magnetic discs comes in several forms.Fixed hard discs are built in to the disc -drive unit,occasionalyly stacked on top of one another .Removable hard dics are contained individually or as stacks (disk packs),in a protective plastic case,and can be taken out of the drive unit and kept for later use.A floppy disc(or diskette)is the most common form of backing store for microcomputers.It is much smaller in size and capacity than a hard disc and is so called because it is manufactured form thin flexible plastic coated with a magnetic meterial.