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Distributed systems are computer systems that are connected by a communication network or any technology that features by the delay in its communication. In addition, these systems present absence of a share clock and shared memory. As a consequence of these absences, it is not easy to observe which order of execution trace of a distributed system because events (eg. sending and receiving of messages) generates by computer systems are not causally related necessarily. There are algorithms that are able to determine which is the causal relation between two events, therefore, these algorithms can partially determine which is the order of an execution trace of a distributed system. The Vector clocks algorithm is widely used to observe the order of a distributed system execution trace.
As OTM supports the definition of entities that observe and react to a system execution trace in web applications, we have extended our prototype to observe and read to distributed system execution traces. OTM uses the vector clocks algorithm. Next, we present two examples, where OTM observes distributed execution traces.