Windows NT
    The kernel records a process's creation time and the CPU time it has consumed including the time spent in user mode and time spent in system mode. 

    Processes may also have their own interval timers, which may be single shot or periodic. These can use signals to notify the process when timers expire.

    Timer objects exist as an Executive support service which will record the passage of time. After a set time or on expiry of a time interval the object becomes 'signalled' which will release all waiting threads.