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:
“Don: Why are they closed? They’re all closed, every one of them.
Pawnbroker: Sure they are. It’s Yom Kippur.
Don: It’s what?
Pawnbroker: It’s Yom Kippur, a Jewish holiday.
Don: It is? So what about Kelly’s and Gallagher’s?
Pawnbroker: They’re closed, too. We’ve got an agreement. They keep closed on Yom Kippur and we don’t open on St. Patrick’s.”
—Billy Wilder (b. 1906)
“The only people who treasure systems are those whom the whole truth evades, who want to catch it by the tail. A system is just like truth’s tail, but the truth is like a lizard. It will leave the tail in your hand and escape; it knows that it will soon grow another tail.”
—Ivan Sergeevich Turgenev (1818–1883)