How do Harddrives work

What is Hard disk drive ?
A hard disk drive is a data storage device used for storing and reprocess digital information using speedily rotation disks coated with magnetic material. It retains data when power off. 

Parts of HDD :

Magnetic platters : 

• Platters are the round plates in the image above. Each platter holds a certain amount of information, so a drive with a lot of storage will have more platters than one with less storage. 
• When information is stored and retrieved from the platters it is done so in concentric circles, called tracks, which are further broken down into segments called sectors.

Arm : 

• The arm is the piece sticking out over the platters. The arms will contain read and write heads which are used to read and store the magnetic information onto the platters. 
• Each platter will have its own arm which is used to read and write data off of it.

Motor : 

• The motor is used to spin the platters from 4,500 to 15,000 rotations per minute (RPM). 
• The faster the RPM of a drive, the better performance we will achieve from it.

How HDD works ?

• When the computer wants to retrieve data off of the hard drive, the motor will spin up the platters and the arm will move itself to the appropriate position above the platter where the data is stored. 
• The heads on the arm will detect the magnetic bits on the platters and convert them into the appropriate data that can be used by the computer.
• When data is sent to the drive, the heads will this time, send magnetic pulses at the platters changing the magnetic properties of the platter, and thus storing your information. 
• Data is accessed in a random-access manner, meaning that individual blocks of data can be stored or retrieved in any order and not only sequentially. HDD's are a type of non-volatile storage, retaining stored data even when powered off.

Advantages of HDD :

• It is relatively cheaper compare to SDD(solid state drive).
• It has large capacity.
• It is easily available in the market.

Disadvantages of HDD :

• It is less reliable and it's life span is relatively less.
• It has very less speed.
• Power consumption is more.