Distributed system for educational use

The paper describes how five minicomputers used in undergraduate teaching have been linked with, initially, a ring topology. An operating system kernel providing message primitives, already operational for a single site, has been extended for multisite connections and supports a hierarchy of processes according to the Reference Model for Open Systems Interconnection.In parallel, single-site systems based on procedural and rendezvous primitives are being formulated and extended for a distributed system. The aim of this work is to illustrate concepts and mechanisms in an educational environment.