Memory is classified as volatile if the contents of the memory disappear when
power is removed. The main memory used in most computers is volatile — when the
computer is shut down, the running applications vanish.
In contrast, memory is known as nonvolatile if the contents survive even after
power is removed. For example, memory used in most digital cameras is nonvolatile —
the images remain even if the memory is removed from the camera and plugged into a
computer or printer.