Token timing question

[Kyle Butt <doorvole@xxxxxxxxxxxxx>]

I have a question about tokens and time-slicing. Clearly when working with
tokens you need to be aware that operations might block and perform a sanity
check with the data upon returning from a might-block operation. However,
what about time-slicing. When can a process be interrupted by the end of
it's time-slice? How does a process know that this is happening? If someone
could explain or at least point me to the right rtfm url, it would be greatly
appreciated.

Thanks,
   Kyle.