US Patent 7290203 Dynamic memory architecture employing passive expiration of data

Apparatus for passively tracking expired data in a dynamic memory includes an error encoding circuit operative to receive an input data word and to generate an encoded data word which is stored in the dynamic memory. The apparatus further includes a decoding circuit operative to receive an encoded data word from the dynamic memory, to detect at least one or more unidirectional errors in the input data word read from the dynamic memory, and to generate an error signal when at least one error is detected, the error signal indicating that the input data word contains expired data. Control circuitry included in the apparatus is configured for initiating one or more actions in response to the error signal.