An approach to high-level debugging of distributed systems (Preliminary Draft)

ABSTRACT

As part of a study of methods and strategies for problem solving in a distributed environment [Less80], we have been investigating techniques suitable for use in debugging programs written for implementation on distributed processing networks. Traditional debugging methods emphasize techniques that apply at the level of computation units and generally allow users to examine, and possibly alter, the state of a computation. Interactive debugging monitors are probably the most powerful implementations of the traditional method and usually permit a user to examine an entire snspshot of system state at any step of the computation. It is the job of the debugger (usually a person directing the error search) to determine what units are relevant to some problem, examine the units in whatever fashion is available, and then fit the results of these examinations into a model of how the computation works. Two elements essential to the successful completion of the debugging task are evident here: the ability to monitor, in some meaningful way, the relevant system activity so as to understand how system behavior differs from the debugger's model, and the ability to perform experiments based (implicitly or explicitly) on the information gathered. Through the interaction of these two elements a debugger attempts to gain an understanding of the causes of an error or at least to note where the implementation and the expected behavior differ.

REFERENCES

• 1: Peter C. Bates and Jack C. Wileden, "EDL: A Basis For Distributed System Debugging Tools," Proceedings of the Fifteenth Hawaii International Conference on System Sciences, (1982) pp.86-93.
• 2: Peter C. Bates, Jack C. Wileden and Victor R. Lesser, "A Debugging Tool for Distributed Systems," Proceedings of the Second Annual Phoenix Conference on Computers and Communications, (1983) pp.311-315.
• 3: Philip H. Enslow, "What is a 'Distributed' Data Processing System", IEEE Computer, Vol. 11, no. 1, pp. 13-21, Jan. 1978
• 4: Leslie Lamport, Time, clocks, and the ordering of events in a distributed system, Communications of the ACM, v.21 n.7, p.558-565, July 1978 [doi>10.1145/359545.359563]
• 5: V.R. Lesser, P. Bates, R. Brooks, D. Corkill, L. Lefkowitz, R. Mukunda, J. Pavlin, S. Reed, and J.C. Wileden, "A High Level Simulation Testbed for Cooperative Distributed Problem Solving," Technical Report TR-81-16, Department of Computer and Information Sciences, University of Massachusetts, (1981).
• 6: Victor R. Lesser and Daniel D. Corkill, "Functionally Accurate, Cooperative Distributed Systems," IEEE Transactions on Systems, Man and Cybernetics, Vol. SMC-11, no. 1, pp. 81-96, Jan. 1981.

INDEX TERMS

Primary Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
      D.2.5 Testing and Debugging
          Subjects: Debugging aids

Additional Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
      D.2.5 Testing and Debugging
          Subjects: Monitors
  D.4 OPERATING SYSTEMS
      D.4.7 Organization and Design
          Subjects: Distributed systems

General Terms:
Design, Languages, Verification