1. A method of operating an erasable and re-programmable non-volatile memory system, which comprises, in response to receiving a command from outside the memory system: perform any function necessary to execute the command, assert a busy signal outside of the memory system for a time extending beyond that utilized to perform said any necessary function, and performing during the extended busy signal time at least a portion of one housekeeping operation within the memory system that is unnecessary to execute the received command, wherein said command has a time budget for its executions, and said busy signal is asserted for a time remaining within the time budget.