Jan 12, 2014

A Personal Analog Computer Story

EAI-680 Analog Computer

During my undergraduate years, I took many mechanical engineering courses. In one course, we were modeling an automotive suspension (springs, shocks and the rotating mass of the wheels going over a conveniently sinusoidal road surface). Capacitors and resistors were used in the model, of course. Then we went to the lab and our task was to properly connect wires to appropriate banana jacks on this big patch panel to set up the simulation. The patch panel was to be connected to an old computer, I was told. I realize now that was an analog computer. The computer itself didn’t work, however, so the professor merely checked our panel to see if it was set up correctly. Not the rewarding feedback it could have been.

Today, none of my classmates seem to remember this. The photo that most closely matches my imagination is this EAI-680 analog computer. Except the panels were a bit smaller – slightly more than one-foot square based on my fading memory.

This was the mid-1980s; I’m not so old that my college needed analog computers (although they retired the punch-card programmers the year before I got there). Analog computers like this were transistorized, but they evolved directly from vacuum tube models. In searching for the type of computer I used, I came across this lone record of a “personal” analog computer from 1963 which I’ll quote directly.

The idea of a personal computer in 1963 is enchanting (and way ahead of its time)! The Pastoriza Personal Analog computer was designed to be used by students at the Case Institute of Technology (which later merged with Western Reserve University in 1967 to form Case Western Reserve University). These computers were issued to 200 students in late 1962 or early 1963 by the school for use in their linear systems course. The students were part of a study to compare students who used slide rules with those who had their own analog computer. The computer was designed by Dr. James Reswick, who was then Head of the Case Engineering Design Center, James Pastoriza (who manufactured them and for whom they were named) and George Philbrick who was already well known as one of the founders of the analog computer systems.
The computer was battery powered and built into a small case so that it was easily portable. They consisted of several modular units that could be configured however the student wanted. 
Dr. Reswick demonstrating the personal analog computer

Reswick had been at MIT and is now best known for his work in rehabilitation engineering. Philbrick, of course, is a legend in the analog industry. Pastoriza worked for Philbrick at one point. Rumor has it that Philbrick actually gave Pastoriza the company that became Pastoriza Electronics. In 1969, Analog Devices bought out Pastoriza Electronics to get into the modular analog-to-digital converter business.

Everything is connected in this business. You don't have to go back very far.



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