1. In a data processing system including at least one central subsystem and a plurality of peripheral subsystems wherein data signal groups are transferred between a central subsystem and a selected peripheral subsystem as a result of an exchange of a plurality of signal groups between said central subsystem and said selected peripheral subsystem, said signal groups including control signal groups and said data signal groups, an input/output apparatus, coupling said central subsystem and said peripheral subsystem, comprising: (a) first input means for receiving signal groups from said central subsystem to distribute said signal groups within said input/output apparatus; (b) first output means, coupled to said first input means, for transmitting signal groups to said selected peripheral subsystem; (c) second input means for receiving signal groups from said peripheral subsystem; (d) second output means for transferring signal groups to said central subsystem; and (e) processor means, coupled to said first and second input means and said second output means, for storing file signal groups from said central subsystem in response to a first preselected signal group from said peripheral subsystem, said processor means producing address signal groups from said file signal groups, said processor means delivering said address signal groups to said second input means in response to second preselected signal groups, said address signal group determining a location in said central subsystem of said data signal group involved in said transfer, said processor means providing that said first input and said first output means operate independently of said second input and said second output means.