JLM,
This test checks if the parallel port controller circuitry of the I/O chip is working. It does this by writing data to the parallel port and reading back the data for comparison, reporting any errors in the test log.
If the test fails, it is an indication that the controller may be bad.
In order for this test to pass the parallel port must be set to bidirectional mode and the loopback connector installed; ECP, EPP or bidirectional are the words used in most BIOS' for this.
-Fred