A method of transferring multimedia data from an input device to an output device in a computer system having a plurality of input/output devices. An application program specifies an origination and destination of multimedia data transfer and orders multimedia data transfer start. A periodic driven program conducts multimedia data transfer in accordance with the order given by the application program. The application program can conduct other processing irrespective of the multimedia transfer state after giving the transfer start order. The periodic driven program operates with a predetermined period, divides multimedia data, and transfers the multimedia data in a plurality of periods.