There are three categories of messages logged in the log files. These are described below.

• Information – This type of message is preceded by a lower case 'i'. It indicates messages containing general information about the events being logged. Each message of this type has four parts – the event information, the module generating the event, the machine on which the event took place, and the date and time of the event.
  
• Warning – This type of message is preceded by a question mark '?'. It indicates messages containing warning notes to the users about the events being logged. The messages of this type have a structure similar to the 'Information' messages with the same four parts mentioned earlier.
  
• Error – This type of message is preceded by an exclamation mark '!'. It indicates messages containing details about errors that occur. The messages of this type have the four parts found in the other two message categories. In addition it has the 'Exception Stack Trace', which occurs before the machine name and date/time. It can be identified by the keyword 'Source' and it can be used to trace the source of the error.