HDD ( Hard Disk Drive ) BASICS

 

HDD ( Hard Disk Drive) is a electromechanical data storage device. It is used to store digital information.

 

  • Accessibility of data in HDD: Data can be randomly accessed from HDD.
  • Retention of Data in HDD: Data stored in HDD is non volatile data.

 

Below is diagrammatic representation of data for HDD

 

Architecture of HDD

 

A hard-disk drive is made up of 4 mechanical components.

 

  1. Platters
  2. Read/Write Heads
  3. Actuator
  4. Spindle motors

 

  1. Platter: Data is stored at platter. It is circular disk as shown in the figure. Platter is made up of glass or aluminium substrate. Its surface is thin, flat and smooth. 

2. Read and Write Heads: These Read and Write heads fly over the platter and are responsible for reading and writing of data.

  • Writing to platter :  When read/write head passes over platter it magnetizes the surface of a platter. This magnetization represents either binary zero or one
  • Read from platter: When read/write head passes over platter it detects magnetic charges and determines binary zero or one.
  1. Actuator: Actuator assembly helps the physical movement of Read and Write heads.
  2. Spindle Motors: Spindle motor helps to spin the platters( disk).