Secondary memory is not directly accessible to the CPU. Input/output channels are used to access this non volatile memory. This memory does not lose the data when the system is powered off. The most familiar form of secondary memory that is widely used is Hard Disk. Some examples of secondary memory are USB sticks, floppy drives and Zip drives.

Optical Disc Storage

Optical Disc Drives use electromagnetic waves or laser light to read and write information to optical discs. There are drives that only read while on the other hand some drives are also there that performs both reading and writing. These devices include CD, DVD and Blue-ray Disc.

Magnetic Tape Storage

The device that performs reading and writing of data on magnetic tapes is a tape drive. Tapes can be cost effective while storing large amounts of data. Today they are largely used for backups and archives.

Hard Disks

A Hard Disks Drive (HDD) is a non volatile secondary storage device which stores digitally encoded data on the magnetic surface of it.