Dan Price did some interesting optimisations to one of the undervalued, but nevertheless important processes of an operating systems. He was able to yield vast speedups in halting the system. There are two methods: A violent shutdown (triggered by reboot, halt or poweroff) and a non-violent shutdown (it´s triggered by shutdown and stops the services in their order of dependency, just backwards). The later one was really slow: roundabout 45 seconds on his test system and many people think the system crashes at shutdown on their systems. Well, Dan describes the optimizsation that brought down the time needed for a shutdown from 45 seconds to 7 seconds in “Speeding to a halt”. Worth a read as this optimisation will find its way into OpenSolaris 2009.next. It´s a little bit older but with the surfacing of 110a in the OpenSolaris repository many people are really positively surprised about the changes to this undervalued part of Solaris.