THUDS: A HIGHLY AVAILABLE DISTRIBUTED COMPUTER SYSTEM.

A distributed computer system is characterized by three main features: modularity (resource distribution), parallelism (processing distribution), and autonomy (control distribution). All these characteristics are necessary in order to provide a system with a series of advantages of distributed processing. THUDS is an experimental distributed computer system intended to satisfy all these requirements. The system architecture of THUDS based on the group-shuffle interconnection network with mixed static and dynamic topologies is stated and evaluated to verify its high performance, especially its high fault tolerance capability. The implementation scheme, including the interconnections among processor-switch pairs, the distributed routing algorithm, and the fault tolerant control strategy, is described. The structure of the high-level message-based software system of THUDS is given. This software system includes a distributed programming language DM based on modula-2 and a distributed file management system based on the original operating system of the resource computer.