User:Bhagyashri.kantikar/sandbox

= TYPES OF EXTERNAL STORAGE=

Magnetic storage devices
Data is stored in the form of magnetized dots.These dots are created,erased,read using magnetic fields created by small electromagnets. In the case of magnetic disks,these dots are arranged in circles on the surfaces of plastic,metal,glass disk that has magnetic coating. 1) Cassette Tape -commonly known as compact cassette.

2) Floppy Disk - These are small, removable, media storage devices.They record data onto the thin, circular magnetic film (which is coated with the magnetic compounds like iron oxide,cupric-ferrous oxide according to the density required) encased in a flat square plastic jacket.It consists of different parts which provides different features like, rigid plastic case which stabilizes the disk when it spins,media access hole and metal shutter covering the hole and using the disk jackets when only required,media indicator hole that designates the disk as high density.Storage capacity of floppy disk is 1.44MB.5.25',8' are previous standard floppy disks and 3.5' is much standard floppy disk.These are readily portable and easily transfer the software from one PC to another.As they lack in storage capacity and slow as compared to hard-disks ,they are not included in products as a built-in storage-option.

Solid state storage devices
1 Punch Cards : It is a storage medium made up of thin cardboard stock which holds data in the form of punched holes.In this data is fed into the computer in the form of rectangular holes.They are of different sizes and different shapes.Also called as Hollerith cards as he developed the method of storage and retrieving data in early 1990s.