Problem(s) Encountered:

When I used owl,there were several errors.

INFO - Checking DS9 version ...  done      
ERROR - Driver  PCI Device 0  failed to open
ERROR - ( CArcPCI::Open() ): Failed to open device ( /dev/astropci0 ) : ( errno: 16 ) - Device or resource busy
ERROR - Not connected to any controller!

Solution:

There were multiple instance of Owl running.  The hint is the line about “device or resource busy”.  I went in and killed all Owl processes.  I also closed a bunch of excess terminals and web browsers to reduce memory usage.  I restarted Owl and verified connectivity and functionality.  All is well.