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

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