The Status/Event Logging System (SLS) logs status and event messages sent by the IPOPP components. It is the primary system monitoring and diagnostic tool and provides the first indication of system problems or anomalies.

The SLS Console displays logged messages. Messages can be viewed in real time or replayed from a selected time span. Message filters allow the display of elected messages.

The SLS consists of the following:

• a logging library interface
• a log server
• the SLS console
• rotating log files

Each IPOPP processing element includes an SLS logging library interface and uses that interface to send messages to the log server. The SLS log server enters and retrieves messages from a set of rotating log files and controls the file rotation. Messages are entered into the active file sequentially until the file reaches a specified size. The file is then closed, the next log file is opened, and this procedure is repeated. The number of log files is specifiable. Eventually log messages will be overwritten, but the allowed size and number of files will be sufficient to preserve messages for at least 72 hours.

Diagnostic and status display application modules will retrieve messages through the SLS logging library interface. The log server and the library interface will make transitions from one log file to another transparent to the application. SLS messages contain the following:

• date/time
• source (i.e., originating processing element or subsystem);
• subsystem-specific parameters;
• severity;
• thread/stack trace
• free text fields