<p>A data processing unit is adapted to exchange data with another data processing unit via a network. The data processing unit comprises a main storage (17) for storing programs and data, an instruction processor (16) for issueing transfer requests by executing programs stored in the main storage (17), and a transfer processor (15) for enqueuing the transfer requests from the instruction processor (16) into a transfer request queue, and for carrying out a transfer process between the main storage (17) and the network based on each tranfer request which is obtained from the transfer request queue. Furthermore, the data processing unit comprises a counter (130) being updated by the transfer processor (15) every time the transfer process is carried out based on the transfer request. The counter (130) is accessible by the instruction processor (16) so that the instruction processor (16) can recognize an end of the transfer process from the content of the counter (130). <IMAGE></p>
