Friday 31 January 2014

HARD-DISK

 

HARD-DISK



Hard disk is one of the most important and beautiful part of every desktop computer.
Just think how all the computers remember things even after the power is switched off. It’s all because of this beautiful hard disk.
Hard disks were initially called as "Fixed disks" or "Winchesters".
The capacity of the hard disk is between 10 and 40 gigabytes.


What is inside the hard disk?

 




The hard disk uses magnetic field for data storage.
The magnetic material is covered by aluminum or glass disk.
It contains series of platters, arm and a motor.
Motor is used to spin the platters.
The platters spin at 3,600 or 7,200 rpm.
The arm moves from the hub to the edge of the drive.
The movement of the arm is up to 50 times per second.


Storage in hard disk:

 

 


It uses magnetic field to store the data because the data can be easily erased and rewritten.
Data is stored in the disk in the form of files.
A file is a collection of bytes.
When a file is requested, the hard disk retrieves its bytes and sends them to the CPU one at a time.
The data is stored on the surface of the platter in sectors and tracks.
To increase the storage capacity of the hard disk, the number of platters should be increased.



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