On error, the buffer can be dumped into the log. Trace messages have seven predefined levels. Lower levels typically contain more detail. Which levels are logged can be changed at launch time or runtime. Which levels are logged can be set independently for different subsystems.
Log files can have a fixed size.
Versioning can be used to protect old log files or the contents of logfiles that fill up. This guide has four more sections. Background material and definitions . There are links from the other sections to terms defined here. You may be able to skip this section, except for the first part .