EMAS - reliable, efficient, portable multi-user OS (Edinburgh, '70 to '92)

A trove of information, papers and a presentation by Bob Eager of a very well-used and long-lived operating system, written by a tiny team out of necessity, used at Edinburgh and Kent universities.

Some nice mentions of patching microcode - faulty hardware being one of the difficulties.

Here’s the presentation as a video:

The Edinburgh Multi-Access System (EMAS) project started in 1966, and resulted in a real service to users from 1971, running on an ICL System 4/75. In 1976, work started on porting this to the ICL 2900 series, and a service was offered from October 1978. The University of Kent took up the system, and offered a service from late 1979. A further port was made to IBM and IBM clone systems, with the final service being closed in 1992.

There’s an effort to resurrect EMAS in simulation, relatively well-advanced.

Nice paper title (1977):

An Experiment In Doing It Again, But Very Well This Time
The famously named paper on the process of re-implementing EMAS on the ICL 2900.

I particularly recommend the collection of anecdotes:

Some EMAS and ICL 2900 related anecdotes are here:

(I was at Edinburgh Uni in 1983/4, and used IMP, but had no idea it was such an early language.)

via @drogon on anycpu


Many details especially by Graham Toal we have in this thread

The facebook project (for an emulation) is here (rather few news)

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