Thursday, January 19, 2017

Secondary Storage

Secondary Storage

Secondary Storage
It has three types.

  1. Magnetic Disk
  2. Optical  Disk
  3. Flash Memory
Magnetic Disk

It is most widely used storage media for all type of computer.A magnetic disk is a thin circular metal plate or platter coated `with magnetic material.Information disk is can be record on or read from the magnetic surface through magnetism. Magnetic disk is a random access media .

Type Of  Magnetic Disk
There are the following of the magnetic disk.
  1. Hard Disk
  2. Floppy Disk
  3. Zip Disk 
Optical Disc

Optical disk issued laser technology to read or write information.LASER stand for Light Amplification by Stimulated Emission of Radiation Laser beam is user to make time holes on the surface of the disk.

Compact Disk(CD)

Cd is the most popular optical medium. It can hold 650 MB to 800 MB of data.the data on the CD cannot be erased like magnetic diskettes.

DVD

DVD, also known as "Digital Versatile Disc" or "Digital Video disc", is an optical disc storage media forma. Its main uses are video and data storage.DVDs are of the same dimensions as compact discs(CD),but store more than six times as much data.

Blu-Ray Disc

Blu-Ray Disc (official abbreviation BD) is an is optical disc storage medium designed to supersede the DVD format. The standard Physical medium is  12 cm plastic optical disc, the same size as DVDs and CDs. Blu -Ray Discs contain 25 GB per layer.with dual layer discs (50 GB)the standard for feature-length video discs and additional layers possible in the future.

Flash Memory And Drive 

Flash memory is a non-volatile computer storage chip that can be electrically erased and re-programmed. It is primarily used in memory cards,USB flash drives, Mp3 players and solid-state drives for general storage and transfer of data between computers and other digital products. Its is a specific type of  EEPROM (electrically erasable programmable read -only memory) that is erased and programmed in large blocks; in early flash the entire chip bad to be erased at once. 

USB Drive

A USB flash drive consists of a flash memory data storage device integrated with a USB (Universal Serial Bus) interface.USB flash drives are typically removable and re writable, and physically much smaller than a floppy disk.Most weight less than 30g. Storage capacities in 2010 can be as large as 256 GB with steady improvements in size and price per capacity expected . 




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