On-line testing for application software of widely distributed system

Widely distributed systems are constructed step-by-step over a long lime. These systems must permit on-line testing. On-line testing verifies newly added application software by receiving the real data in the real environment without disrupting the operating subsystems. To enable testing during system operation, an on-line test technique based on autonomous decentralized system structure was proposed. In this paper, the functions to verify various types of application software are proposed: (1) for non-real-time application software, checking whether it communicates with every operating application software. (2) for real-time application software, checking whether timing of output data is within the timing-deadline or not. (3) for new version software, verifying whether the version of all functions is newer than that off functions in the present software. An example of application software applied to the on-line test and the effectiveness of the technique is shown in a real system