Magnetic memory uses properties of magnetic for storing data. It is the first technology used for storing data. Many magnetic memories are not used at present. However hard disk is still the most popular storage device. It is one of the magnetic memory. The storing surface of magnetic memory is made by metal or plastic. This surface is coated by magnetic oxide. According data storing surface magnetic memory can be magnetic disk, magnetic tape and magnetic drum.
I) Magnetic drum:- It was used in 1st and 2nd generation of computers. It used cylindrical drum made by metal.l The outer side of the drum used for storing data. The srorage capacity of this device was in the range of few KB to MB.
II) Magnetic Tape:- magnetic tape contents this plastic ribbon coated by magnetic oxide. Data stored one side of ribbon. It is a sequencial access memory so the average data read write speed will be slower. It is highly reliable so ti is mainly use for storing backup, audiovidio file etc. It requireds magnetic tape drive for its readwrite operation. It is use in different storage capacity like 100MB, 250MB, 512MB,1GB,2GB,4GB,10GB,10GB and 20GB. The width of ribbon also varies like one inch, 1/2 inch, 1/4 inch,8mm, 4mm. The typical lenth of magnetic tape is 2400 feet.
III) Magnetic disk:- Magnetic diskk contents multiple circular disk made by metal or plastic. The circular disk rotates during readwrite process. The circular disk is divided into circular areas having common centre. This circular areas is known as track. Tracks are further divided into small area known as sector., Data are stored in the sectors. Some of the magnetic disk memories used are:-
Floppy disk
Hard disk
Winchester disk
Zip disk
Jazz disk
Super disk
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