Memory

Primary memories :    RAM and ROM
Secondary memories : Semi random and Serial access.

Semi Random Memory
    Example : All disc memories  ( CD's  DVD's )
Serial Access
    Example : Magnetic tape , Magnetic bubble ferrite core , CCD ( Charge coupled  device ).

Difference between RAM and ROM

Random Access Memory (RAM)
               There are two type of RAM : static RAM and Dynamic RAM.

 Difference between Static RAM and Dynamic RAM