The architecture of UNIX united

UNIX United is an architecture for a distributed system based on UNIX. As it is compatible with UNIX at the system call level, any program written for a normal UNIX system can be transparently extended to exploit the richer environment of UNIX United. As it relies on having a UNIX system beneath it, the implementation of UNIX United, called the Newcastle Connection, provides an interesting example of the construction of a very powerful distributed system with only a modicum of effort. A description of the basic semantics of UNIX United is followed by that of the architecture implied by the protocol between components in a UNIX United system, and of a software structure appropriate to the architecture and the protocol.