The Advanced Personal Machines (APMs)

The Advanced Personal Machines, affectionately known as Fred Machines in honour of Fred King, their designer, were the result of a project to produce a flexible architecture that would facilitate experimentation with sophisticated computer modules. The first prototypes were built during the academic year 1981-2. The central feature was a common system bus, designed to a minimal hardware specification that allowed attached modules to communicate reliably, leaving other issues to be dealt with by software. Building on the experience gained from creating EMAS, the system software included an IMP compiler and an IMP run-time system, the latter being written in Motorola MC68000 assembly language.

As in most academic environments at that time, there was a conflict of interest between the research and development of computer systems and the demands of the user community for a sophisticated computing service. Satisfying the latter need supplied essential feedback to the former activity but inevitably required systems to have firm specifications and stable behaviour. In the case of the Fred Machine, what was meant to be an experimental workstation immediately became public property. In the summer of 1982, the statement "The Edinburgh Advanced Personal Machine (APM) has been developed in the Department of Computer Science to fulfil its requirements for general purpose computing over the next five or so years"  appeared in publicity accompanying a demonstration of the workstation at a University Open Day, This marked the transition of the Fred Machine from an experimental research and development project to an official computing resource. Ultimately around sixty APMs were constructed, about half of them with colour graphics. They continued in use until the late 1980s.

A more detailed history and an evaluation of the APMs can be found in a Computer Science Research report "The Evolution of the Fred Machine" (CSR-246-87) by Gordon Brebner and Fred King.