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The Human-Machine Monitor

Whenever a WARN_HM is emitted by OutputToHM, HMMonitor resets the HM_READY flag, and data collection from new processors is suspended by ServiceReq's internal Triveni process DoAllProcs. This behavior is expressed using the JavaTriveni SuspRes construct inside the DoAllProcs module: this allows the rest of the Collection Software program to remain unpolluted by information about HM_READY, while giving high-priority to this event. HMMonitor then periodically checks if the HMI is responding. Once the HMI starts responding, data collection is resumed. If it does not respond in a threshold number of queries, HMMonitor sends an ABORT_ALL to ServiceReq's internal Triveni process ProcessReq, and the summary request is aborted. The nesting structure of the SuspRes construct for HM_READY and the DoWatching construct for ABORT_ALL give the desired dynamic priorities among these events, depending on the number of times the HMI has been queried.



1998-03-16