Messages Sent to USM

Following is the specification of the Epina ImageLab messages:

Message Key	Parameters	Explanation & Details
LISTENING	none	Epina ImageLab is waiting for status messages until the "DONEEXIT" message is received.
KILL	none	Epina ImageLab requests the USM to abort any tasks and to kill itself. Epina ImageLab then waits until the USM has sent the 'DEAD' message and deletes the semaphore (both files).