Secondary memory is computer memory that is non-volatile and persistent in nature and is not directly accessed by a computer/processor. It allows a user to store data that may be instantly and easily retrieved, transported and used by applications and services. Secondary memory is also known as secondary storage.
A part from the main memory there is one more memory in which the information is stored on an external device, that device are called the secondary or external storage device and the memory is called secondary memory.
Secondary memory is slower than primary memory but can store and retain data, even if the computer is not connected to electrical power. It also has substantial storage capacities, ranging from megabytes to several terabytes of storage space within single memory.
There are some examples of Secondary Memory:-
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Floppy Disk:-
A floppy disk, also called a Floppy, Diskette, or just Disk, is a type of disk storage composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic enclosure lined with fabric that removes dust particles. Floppy disks are read and written by a floppy disk drive (FDD).
A floppy disk is used to store information just as a hard disk. It store data magnetically. It is a removable storage device.
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Hard Disk Drive:-
Hard disk is a storage device in which computer stores data. Hard disk is also called hard drive. Most computers have one hard disk located inside the computer case. Hard disks can save time because accessing files on hard disk is almost 20 times faster than on Floppy Disks. It could store 40 G.B to 1 P.B of Data.
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CD-ROM (Compact Disc):-
CD-ROM is contains data accessible by a computer. CD-ROM is popularly used to distribute computer software, Games and multimedia Applications. A standard 120 mm CD-ROM holds 650 or 700 M.B of Data.
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D.V.D (Digital Versatile/Video Disc):-
D.V.D is also an optical medium of data storage. The current capacity of D.V.D is up to 4.74 G.B.
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U.S.B (Universal Serial Bus):-
These devices are used to transfer data from one computer to another computer.
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Tape Drive:-
A tape drive is a data storage device that read and writes data on a magnetic tape. Magnetic tape data storage is typically used for affine, archival data storage.