< storage > (NVS, persistent storage, memory) A term describing a storage device whose contents are preserved when its power is off. Storage using magnetic media (e.g. magnetic disks , magnetic tape or bubble memory ) is normally non-volatile by nature whereas semiconductor memories ( static RAM and especially dynamic RAM ) are normally volatile but can be made into non-volatile storage by having a (rechargable) battery permanently connected.
Dynamic RAM is particularly volatile since it looses its data, even if the power is still on, unless it is refresh ed. An acoustic delay line is a (very old) example of a volatile storage device.
Other examples of non-volatile storage are EEPROM , CD-ROM , paper tape and punched cards .
(2000-05-22)