Debugging distributed programs is inherently more difficult than debugging sequential process programs. Firstly, distributed programs bear a new dimension of problems in that interactions among processes are asynchronous because there are no global clock governing processes and there can be unpredictable communication delay in those interactions. Secondly, there are a few tools available to help programmers to understand and debug the distributed programs.
We, in this paper, suggested and implemented the primitives for interactive monitoring of distributed programs. We integrated Berkeley's Distributed Programs Monitor and 4.2BSD debugger and made up distributed debugging environments, called Pagoda Distributed Programs Monitor. Pagoda Distributed Programs Monitor suggested in this paper can not only know the characteristics of distributed programs, but present the environments for distributed debugging. Pagoda Distributed Programs Monitor is an active tool, while Berkeley Distributed Programs Monitor is a passive tool.
