The file I/O trace is an EBCDIC encoded trace that can be used
as a debugging aid for file I/O failures. The files that are traced,
the level of detail provided by the trace, and the trace table size
can be controlled with the environment variable _EDC_IO_TRACE. For
more information about _EDC_IO_TRACE, see _EDC_IO_TRACE. Figure 1 shows the result of running a file I/O application
with the displayed environment variable setting.