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Re: Transputer - schools

On 29 Jun 2013, at 19:18, Larry Dickson <tjoccam@xxxxxxxxxxx> wrote:

It might be of value for you to cobble up two or three examples where "prioritised vectored interrupts" give a clear advantage over round-robin interrupts (which is what PRI PAR amounts to). The advantage has to be clear, because of the price paid in priority inversions. It always seemed to me that round-robin interrupts were enough to give the required response in most problems - unless you did not have enough hardware. And Transputer-style PRI PAR can be implemented on any embedded chip that offers interrupts.
I admit it is a long time since I needed them, and I could nowadays saturate the problem with resources, but the logic remains.

We built astronomical instrumentation.  An example of a high-priority task was the arrival of data, or a telescope about to hit the wall (very crude computer control in them days!), over low-priority tasks like continuing data reduction or temperature control.  Surely auto and aviation control systems have even more demanding behaviour to express.

Perhaps it's just me!

PS Must go off line till late tomorrow now.

Ian East
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