On Wed 06 Dec 2017 at 15:25:10 (-0800), James H. H. Lampert wrote:
> Now, now, you walk up to the physical console on an AS/400, you're
> not going to be able to do a PWRDWNSYS from a sign-on screen, nor
> can do it if signed on as a user who doesn't have sufficient
> authority to do a PWRDWNSYS. And you might be physically locked out
> of the front panel. It's even possible that you might be physically
> interdicted from unplugging the box, or shutting it down from the
> circuit breaker panel.
With the Cambridge University computing service in the days of the
370/165, the cut-off switch was high on the wall in the "cafeteria"
area (self-service card reader and line printer) which was open to
users 24 hours a day.
> Not every OS assumes by default that anybody with physical access to
> the hardware also has the authority to shut it down.
I didn't know we were talking about authority. One of the pastimes
of kids in rough neighbourhoods is to pull the Engine Stop lever
while a bus is picking up passengers.