In addition to the trace facilities that print information to standard output, as described in the previous section, the x-kernel also provides a facility for saving detailed trace information about protocol execution to disk. This data can later be processed by various protocol-specific analysis tools. We anticipate most protocols using the trace facility described in the previous section, rather than the facility given in this section.
This data tracing facility supports operations for creating and managing circular trace buffers, writing trace entries to a buffer, saving traces to a file, and appending ``postamble'' information to trace files..