M8650 async board problem

From: Pete Turnbull <pete_at_dunnington.u-net.com>
Date: Sun Dec 23 04:53:22 2001

On Dec 23, 1:22, Pete Turnbull wrote:
> On Dec 22, 23:15, Tony Duell wrote:
>
> > As the fault wasn't on the M8650, why did they cut that track? Did they
> > just never want interrupts?
>
> I've no idea. It wasn't cut by the previous owner; he doesn't know why
> either.

I've just realised something. The machine was used in a real-time process
control system in the pharmaceutical industry. If that system was designed
as a "hard" real-time system, then interrupts would be verboten, as then it
would be impossible to calculate the worst-case execution times for
scheduling routines. I guess this was built not very long after the
Flixborough disaster in 1974 -- an event still used as an example in
safety-critical systems design courses. My guess is the designers just
eliminated all the unlikely problems they could, as well as the likely
ones.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York
Received on Sun Dec 23 2001 - 04:53:22 GMT

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