Page History
...
The MFS should simply perform any tasks required to clear all pending locks for that filing system. When this task is complete, the MFS should return with status set to true.
Additional Lock Calls
Additional lock calls exist in the system that are not available to MFS programmers. These are calls that the system uses to initialize and reset itself; as a result, these calls are passed only via direct calls at system initialization and reset time.
System lock calls are:
LOCK.SEMAPHORE
UNLOCK.SEMAPHORE
SET.USER.SEMAPHORE
An MFS will never receive these calls, and should therefore simply execute a RETURN for the CODE values of 23, 24, and 25.