A data processing system adapted to distribute a process to a plurality of control units coupled to each other via a communication line (12, 14) to execute a computer program, comprising: a process breaking unit configured to refer to a script code in which a content of data processing is written, and to break the data processing into a plurality of units of processing; a public interface information retaining unit configured to retain as public interface information, a list of interfaces accessible from another control unit, out of the interfaces for controlling the parts of the units of processing assigned to the sub-controllers from an external source; and a distributor configured to assign the units of processing to the plurality of the control units, respectively, wherein each of the control units is a microprocessor unit and comprises: a main controller; a plurality of sub-controllers configured to execute processing assigned by the main controller; and an operating system configured to monitor the execution state of said plurality of sub-controllers in the control unit, wherein a sub-controller is configured to enter a wait state after termination of execution of processing assigned by the main controller; wherein the main controller is configured to assign parts of a unit of processing to a plurality of the sub-controllers in the wait state, and each of the sub-controllers is configured to execute the part of a unit of processing assigned thereto, wherein: the part of a unit of processing assigned to a first sub-controller is configured to post to the corresponding main controller an interface which controls the part of the unit of processing from an external source; and a second sub-controller corresponding to the same main controller as the first sub-controller, different from the first sub-controller, is configured to control the part of the unit of processing executed by the first sub-controller via the interface posted to the main controller; and each of the parts of the units of processing assigned to the sub-controllers is configured to control the part of the unit of processing executed on the another control unit by referring to the public interface information. a process breaking unit configured to refer to a script code in which a content of data processing is written, and to break the data processing into a plurality of units of processing; a public interface information retaining unit configured to retain as public interface information, a list of interfaces accessible from another control unit, out of the interfaces for controlling the parts of the units of processing assigned to the sub-controllers from an external source; and a distributor configured to assign the units of processing to the plurality of the control units, respectively, a main controller; a plurality of sub-controllers configured to execute processing assigned by the main controller; and an operating system configured to monitor the execution state of said plurality of sub-controllers in the control unit, wherein a sub-controller is configured to enter a wait state after termination of execution of processing assigned by the main controller; the part of a unit of processing assigned to a first sub-controller is configured to post to the corresponding main controller an interface which controls the part of the unit of processing from an external source; and a second sub-controller corresponding to the same main controller as the first sub-controller, different from the first sub-controller, is configured to control the part of the unit of processing executed by the first sub-controller via the interface posted to the main controller; and each of the parts of the units of processing assigned to the sub-controllers is configured to control the part of the unit of processing executed on the another control unit by referring to the public interface information.