Q. Explain the differences in terms of cost between the three storage types nonvolatile, volatile and stable.

Answer: Volatile storage refers to main as well as cache memory and is very fast. Nevertheless volatile storage cannot survive system crashes or powering down the system. Non-volatile storage survives system crashes as well as powered-down systems. Disks and tapes are instances of non-volatile storage. In recent times USB devices using erasable program read-only memory (EPROM) have appeared providing non-volatile storage. Stable storage demotes to storage that technically can never be lost as there are redundant backup copies of the data (usually on disk).