Method and apparatus for monitoring a subsystem within a distributed system for providing an archive of events within a certain time of a trap condition

A distributed system comprising:

• a first interacting subsystem including a first clock means, a first sensor operative to detect occurrence of a trap condition, and first logic means responsive to the clock means and the sensor to automatically determine at what time the trap condition occurs and to automatically send a signal notifying another subsystem of the occurrence of the trap condition and the time of occurrence;
• a second interacting subsystem including a second clock means, a buffer, a second sensor operative to automatically collect data respecting the second subsystem, and second logic means responsive to the second clock means to automatically time-stamp data collected by the second sensor and place the time-stamped data in the buffer and responsive to a signal from the first subsystem to automatically archive any of the data in the buffer that carry a time stamp within a desired interval of the time of occurrence of the trap condition and thereby provide a history of the second subsystem during the desired time interval;
• and
• communication means operative to carry signals between the first interacting subsystem and the second interacting subsystem.

In a distributed system of the kind having a plurality of interacting subsystems and communication means therebetween, each interacting subsystem having a local controller and a sensor for gathering data respecting that interacting subsystem, an improvement for monitoring the distributed system over time, the improvement comprising:

• a first local clock reference and a first local buffer in communication with the local controller of a first one of the interacting subsystems;
• means in the local controller of the first interacting subsystem for automatically time-stamping data gathered by the sensor and placing the time-stamped data in the first local buffer;
• a second local clock reference in communication with the local controller of a second one of the interacting subsystems;
• means in the local controller of the second interacting subsystem for automatically detecting occurrence of a trap condition from data gathered by the sensor of the second interacting subsystem, determining at what time said trap condition occurs, and notifying the first interacting subsystem of the occurrence of the trap condition and the time of said occurrence;
• and
• means in the local controller of the first interacting subsystem for automatically archiving any time-stamped data in the buffer that carry a time stamp within a desired interval of the time of occurrence of the trap condition and thereby providing a history of the first subsystem during the desired time interval.