Image courtesy of Dave Fischer.

(This is the story of the EAI TR-48 as told by Dennis Bernstein of the University of Michigan.)

About 15 years ago I bought an old analog computer from Notre Dame University through Mike Sain, an EAI TR-48. My students rented a van and in midwinter drove to South Bend to pick up the TR-48.

It turned out that Mike tossed in for free a 2nd analog computer which was an EAI 580. I never turned on the 580, so I have no idea if it was in working order-although I did use the one that I paid for, the TR48. I still have it. In any event, I just donated the 580 to the Rhode Island Computer Museum.

RICM has asked me about any background information on the 580 relative to its use at NDU by Mike and others (just to be clear-it had NO use at UMich, where it just sat for 15 years (since 1995). I'm wondering if you or anyone at NDU might have any information that they could pass on to RICM. Pleas feel free to forward this email to anyone who might have memory about use of the 580.

Dennis S. Bernstein


Editor in Chief, IEEE Control Systems Magazine

Aerospace Engineering Department

University of Michigan

Ann Arbor, MI 48109

More to all From Notre Dame:

Yes, I remember the EAI 580 computer that I used in EE-571 "Hybrid Computation" that I taught in the Spring semesters of 1973 and 1975: a 4-credit graduate course with three lectures and one laboratory per week. The EAI 580 had an analog patch panel that was not fully populated, and it had a digital patch panel for logic gates and flip-flops that could be used to control the analog integrators. Our machine had a special interface to our Digital Equipment Corporation PDP-8 digital computer, with D to A and A to D converters for data transfers, as well as logic control. It was nice to see the photo of our machine. I will check my file cabinets at ND to see if I still have further information on the EAI 580.

To place this in perspective:

I originated a course in Electrical Engineering at the University of Notre Dame in 1963 entitled Computer Simulation. It was a four credit-hour course with three 50-minute lectures and one 3- hour laboratory per week. It was a popular elective course for seniors and graduate students that I taught once every year from 1963 through 1991, except for 1982-83 when I was on active Air Force duty in the Computer Division at Kirtland AFB in Albuquerque, New Mexico.

The course began with analog computer simulation of dynamic physical systems, and evolved to include hybrid analog/digital simulation as well as digital computer simulation of both continuous and discrete-event systems. The laboratory began by using a Bendix G15 vacuum tube analog computer. It was quickly replaced by Electronic Associates TR-10 and TR-20 solid-state analog computers that I later modified so that they could be controlled by digital- logic training units. The TR-10 and TR-20 computers were also used in control system laboratories for experiments that I developed when I taught the control courses, and later were used by professors Michael Sain and Panos Antsaklas. Professor John Uhran and I used the TR-10 and TR-20 computers in a laboratory course for 105 EE juniors in 1984.

For advanced courses and research projects, we obtained a fully-expanded EAI TR-48, and later we acquired our last analog/hybrid computer - the EAI 580.

Eugene W. Henry, Professor Emeritus

Department of Computer Science & Engineering

384 Fitzpatrick Hall

Notre Dame, IN 46556

There is a museum in Germany dedicated to analog computers.