lock manager/ concurrency

[kilmer.WBST at XEROX.ARPA]

		Hi-

		I need to implement some form of a lock manager under
		4.2bsd for concurrency control.  Are there existing software
		programs that anyone knows of ?  Failing that can anyone
		point me in a direction for implementation ?  I know very
		little of UNIX innards - are there semaphores available, a
		way to disable interrupts (seems a little extreme) or something
		better ?