The present invention relates to an apparatus and method for managing commonly used data which is referred to or accessed by a plurality of programs running on one or more computers.
Conventional computer systems are known, which can run a plurality of programs serially on a time-shared basis so as to look as if the plurality of programs are running simultaneously. In a conventional computer system, common information storage areas for storing common data are assigned in the memory space of the system and are accessible by each of the programs. However, the common data cannot always be accessed by the programs. For instance, while common data is being updated by a program having exclusive control in the system, the other programs are prohibited from accessing that common data while it is being updated. This is a problem because when a program has exclusive control, the processing efficiency of the computer system decreases as all other programs cannot access the common data while it is being updated, and, therefore, the program must wait until the updating process has completed.