Not really; I don't seem to recall our having one on the MIT V6 machine. (We did add a 'reboot' system call so we could reboot the machine without having to take the elevator up to the machine room [the console was on our floor, and the reboot() call just jumped into the hardware bootstrap], but in the source it doesn't even bother to do an update(). Well, I should't say that: I only have the source for the kernel, which doesn't; I don't at the moment have access to the source for the rest of the system - although I do have some full dump tapes, once I can work out how to read them. Anyway, so maybe the user command for rebooting the system did a sync() first.) I suppose you could set the switch register to 173030 and send a 'kill -1 1', which IIRC kills of all shells except the one on the console, but somehow I doubt you're running multi-user anyway... :-) Noel