CHAPTER 5SMF: The Service Management Facility
I get knocked down, but I get up again, 'cause you're never gonna keep me down.
—From the song Tubthumping by Chumbawamba
Much of modern computer hardware is self-monitoring and self-correcting. It tests itself and reports real and impending errors so that preemptive maintenance can be performed, often in the form of "hot swap" components that can be replaced without interrupting system activity. What would a similar approach to system software look like? It would need a framework for identifying and classifying services and their dependencies, for monitoring and reporting their status, and for some form of autorecovery. UNIX has historically lacked such a framework, relying instead on ad hoc solutions ...