MFC: rev. 1.27
MFC: rev. 1.27

Clarify how the 'channel' argument should look like and add an
example on how to obtain information on devices on an ata channel.

Approved by:	re (hrs)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase