Open Systems
Carl Hewitt pointed out that openness was becoming a fundamental challenge in software system development. Open distributed systems are required to meet the following challenges:
- Monotonicity
- Once something is published in an open distributed system, it cannot be taken back.
- Pluralism
- Different subsystems of an open distributed system include heterogeneous, overlapping and possibly conflicting information. There is no central arbiter of truth in open distributed systems.
- Unbounded nondeterminism
- Asynchronously, different subsystems can come up and go down and communication links can come in and go out between subsystems of an open distributed system. Therefore the time that it will take to complete an operation cannot be bounded in advance (see unbounded nondeterminism).
- Inconsistency
- Large distributed systems are inevitably inconsistent concerning their information about the information system interactions of their human users
Carl Hewitt and Jeff Inman worked to develop semantics for Open Systems to address issues that had arisen in Distributed Artificial Intelligence. Carl Hewitt and Carl Manning reported on the development of Participatory Semantics for Open Systems.
Read more about this topic: Actor Model Later History
Famous quotes containing the words open and/or systems:
“Manuel showed her his open hand: Look at this finger, how meager it seems, and this one even weaker, and this other one no stronger, and this one all by himself and on his own.
Then he made a fist: But now, is it strong enough, big enough, solid enough? It seems so doesnt it?”
—Jacques Roumain (19071945)
“We have done scant justice to the reasonableness of cannibalism. There are in fact so many and such excellent motives possible to it that mankind has never been able to fit all of them into one universal scheme, and has accordingly contrived various diverse and contradictory systems the better to display its virtues.”
—Ruth Benedict (18871948)