Classification of Physical Storage Media Can differentiate storage into: volatile storage:loses contents when power is switched off non-volatile storage: Contents persist even when power is switched off. Includes secondary and tertiary storage,as well as batter-backed up main-memory. Factors affecting choice of storage media include Speed with which data can be accessed ·Cost per unit of data ·Reliability Database System Concepts-7th Edition 12.2 ©Silberscha乜，Korth and SudarshanDatabase System Concepts - 7 12.2 ©Silberschatz, Korth and Sudarshan th Edition Classification of Physical Storage Media ▪ Can differentiate storage into: • volatile storage: loses contents when power is switched off • non-volatile storage: ▪ Contents persist even when power is switched off. ▪ Includes secondary and tertiary storage, as well as batter-backed up main-memory. ▪ Factors affecting choice of storage media include • Speed with which data can be accessed • Cost per unit of data • Reliability