Trace Format Files (.TFF) & Trace Definition Files (.TDF)
Static tracing occurs when a program developer has coded an API call to the system trace interface, which means you cannot specify at what point in the program flow tracing occurs, nor can you control what data is collected.
Trace Format Files are used by TRACEFMT. They specify how the trace data should be formatted. The filename implies which major code is described, and TRACEFMT generates the filename for the .TFF file from the major code of the event about to be formatted. If no description is found, or if the description does not describe all of the trace entry, TRACEFMT defaults to hexadecimal bytes for a default formatting. This will be covered in detail by hands-on exercises.
Trace Definition Files are used for dynamic tracing, and specifying one of them requires you to name the .DLL involved, or KERNEL. You may optionally a type or list of types and a group or list of groups. The .TDF file is used by TRACE to define where to collect data, and what data to collect.
Dynamic tracing occurs when trace definition files ( .TDF ) are used by the TRACE command. The implementation is that OS/2 inserts actual breakpoint instructions at the specified locations, and collects the data specified when the breakpoint is executed. There is no overhead for dynamic tracing when it is not in use, and a technician can be very creative when defining where to collect trace data, and what data to collect. We will create custom dynamic trace entries during hands-on exercises.
The OS/2 static tracepoints do not have associated TDF files, but may have associated TFF files that are used by the TRACEFMT.