(I/O) Communication between a computer and its users, its stORage devices, other computers (via a netwORk) OR the outside wORld. The devices the computer uses to do this are called "peripherals". What actually counts as I/O depends on what level of detail you are considering, e.g. communication between processORs would not be considered I/O when considering a multiprocessOR as a single system. ImpORtant aspects of I/O are throughput, latency, and whether the communications is synchronousORasynchronous (using some kind of buffer). (2003-12-04)