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Lookup NU author(s): Professor Brian RandellORCiD
Two recursive structuring principles which aid the construction of sophisticated distributed computing systems and described, namely that: (i) a distributed computing system should be functionally equivalent to the individual computing system of which it is composed, even with respect to exception reporting (i.e. the information that a system provides to its environment when it is unable, or perhaps even not designed, to carry out a requested operation), and (ii) fault tolerant systems should be constructed from generalised fault tolerant components. (Such components try to tolerate , wherever appropriate, their own faults and those reported to them by underlying components, and also being wrongly invoked - both by the components they interact with and the component of which themselves from part.) The first principle motivates the use of a strict context-relative naming scheme for all objects in the computing system - taken together the principles enable the problems of constructing coherent systems from heterogeneous components, of incorporating fault tolerance and of providing multi-level security, to be greatly simplified by being treated as essentially seperable logical problems. an operational distributed computing based on UNIX* and designed in accordance with these principles is used for illustration. This system has been implemented by adding a software subsystem, known as the Newcastle Connection, to each of a set of UNIX systems, so as to construct a distributed system which is functionally equivalent at both the user and the progress level to a conventional uniprocessor UNIX system. Prototype extensions of the system, providing multi-level security and hardware fault tolerance, have also been produced, and are briefly described, as are plans to incorporate non-UNIX systems into the overall distributed system.
Author(s): Randell B
Publication type: Report
Publication status: Published
Series Title: Computing Laboratory Technical Report Series
Year: 1982
Pages: 22
Print publication date: 01/12/1982
Source Publication Date: December 1982
Report Number: 181
Institution: Computing Laboratory, University of Newcastle upon Tyne
Place Published: Newcastle upon Tyne
URL: http://www.cs.ncl.ac.uk/publications/trs/papers/181.pdf
