Editing Computer data storage (section)

=== Volatility ===
[[Non-volatile memory]] retains the stored information even if not constantly supplied with electric power. It is suitable for long-term storage of information. [[Volatile memory]] requires constant power to maintain the stored information. The fastest memory technologies are volatile ones, although that is not a universal rule. Since the primary storage is required to be very fast, it predominantly uses volatile memory.

[[Dynamic random-access memory]] is a form of volatile memory that also requires the stored information to be periodically reread and rewritten, or [[memory refresh|refreshed]], otherwise it would vanish. [[Static random-access memory]] is a form of volatile memory similar to DRAM with the exception that it never needs to be refreshed as long as power is applied; it loses its content when the power supply is lost.

An [[uninterruptible power supply]] (UPS) can be used to give a computer a brief window of time to move information from primary volatile storage into non-volatile storage before the batteries are exhausted. Some systems, for example [[EMC Symmetrix]], have integrated batteries that maintain volatile storage for several minutes.