Debugging dynamic distributed programs using global predicates

The authors describe a debugger for distributed programs based on a replay technique. Distributed programs may dynamically fork child processes and open and close communication channels between processes. This debugger features breakpoint setting and selective trace commands with global predicate conditions called conjunctive predicate and disjunctive predicate, which are related to multiple processes. It can halt or test the processes at the first global state for a given conjunctive predicate breakpoint condition. The authors have developed a prototype distributed debugger ddbx-p on UNIX 4.2 BSD.<>