PURPOSE: To reduce contention between tasks simultaneously accessing a common block by a code sequence compiled from a FORTRAN-like language system by dynamically connecting the common block to the task and scoping the connection within the range of the dynamic nesting of the task. CONSTITUTION: At the time of first sub task calling, including the recording of a pointer for pointing the common block in a sub task description, at least one common block is dynamically connected to a sub task so as to be specified by a high-order task and the pointer inside the sub task for pointing the position of the copy of the common block known to the calling high-order task is updated. Thus, the contention between the tasks simultaneously accessing the common block by the code sequence compiled from the FORTRAN-like language system is reduced, the use of the common block in the parallel execution of plural levels is facilitated and a memory used at the time of storing the private copy of the common block is reduced. COPYRIGHT: (C)1990,JPO