A processor system having one or more stations (22, 24, 26) which are interconnected by a general communication network (20). Each station has one or more processors (34, 36). Superprocesses (74, 76, 78) which have one or more processes (80-90) can be executed in the stations. Each superprocess is provided with mail-box space (50, 52, 54) for communication with the environment, in which mail-box space the relevant superprocess and other superprocesses can write but in which only the relevant superprocess itself can read. Processes within the same superprocess have variable data in common, but their register stacks are private. Each mail-box is provided with a filling indicator. In the case of a read operation in an empty mail-box space, a wait signal is issued for the initiating process; write operations in a full mail-box space produce an error signal. There is also provided a job control system for allocating jobs among the stations by way of an application load file.