A method is disclosed that places data-intensive subprocesses in close physical and logical proximity to the facility responsible for storing the data, so that high efficiencies at reduced cost are achieved. In one specific example, new computer programs, termed adjuncts, are added and placed in a logical partition on a storage facility so that they can be invoked using appropriate commands issued on the I/O channel. Further, programs or changes are added to existing programs on the host machine, wherein such programs or changes discover the function extensions and invoke them to perform data processing.