Secondary Memory

Secondary memory:

                The secondary memory is the permanent memory where information are stored for future use. The stored information can be system instruction , programs, user documents etc. Secondary memory is also called mass storage. It is very inexpensive as compares to primary memory . But it is slower than primary memory. Secondary memory are: Hard disk, floppy disk, Magnetic tape,  Zip disk, Super disk, Flash disk, CD, DVD etc.

On the basis of storage temporary secondary memory  mediums are categorized into two types.

                1. Magnetic Storage Media

                2. Optical Storage Media

                Magnetic Storage Media:

                                It uses magnetically sensitive material such as iron oxide to store data on it. The most common magnetic storage media are hard disk, floppy disk, tape disk and zip disk. The read/write head of the magnetic storage device consists of an electromagnet which reads data from and write data to the magnetic storage media.

Some magnetic storage media are Magnetic Tapes, Floppy disk, Zip disk, Super disk, Hard disk.

Optical Storage media:

        They provide a huge storage capacity. Optical storage device uses light technology to read data from and write data to the optical medium. In optical disks, data are stored in the form of lands and pit. Land is a surface which reflects light, representing data bit 1 but pit is a rough surface which scatters light, repepresenting data bit 1 but pit is a rough surface which scatters light, representing data bit 0.
The most popular optical disks are CD-ROM, CD-RW and DVD-ROM