6 common storage technologies 0

           
1. Semiconductor memory  
                 
These memories make use of IC's made up of semiconductor materials. It contains millions of transistors and capacitors. There are volatile and non volatile memories. ROM, magneto resistive RAM, flash memory etc are non volatile memories. SRAM and DRAM are the common volatile memories.  

2. Magnetic storage   

 

  

This is the method of storing data using various magnetisation patterns on magnetic materials. It is non volatile. Data are read and write using read god write head. Floppy disc and hard disc are disc shaped magnetic storage devices. Magnetic storage are also utilised in MICR of bank cheques and magnetic stripes in credit cards. Magneto resistive RAM is an advanced technique of magnetic storage. In this technique data are stored using tunnel magneto resistance.

3. Optical storage 
 

These are the most used storage technologies today. LASER is used to read and write data. Compact disc, DVD, Blue ray disc etc are the examples of optical storage.

4. Magneto optical.                         

In this method data are stored in magneto optical discs. They can be formated to special file system.  Operating system misunderstand these optical devices as hard disc.
                              
5. Optical tape         

Data are stored in long plastic tapes. They combines the technologies of both cinema film and optical disc. While a magnetic tape can store 10-50 GB, an optical tape can store upto 1TB.
                  
6. Phase change memory                       

The change in phase between crystaline and amorphous states by the action of heat is used in these types of memories. PCM, PRAM and CRAM are this type of memories.