Jay W. Forrester, a pioneer in computer models, has died | Hacker News Reader

Jay W. Forrester, a pioneer in computer models, has died

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"He recalled in 2011 that he once asked students in an engineering class if they understood how the feedback mechanism in a toilet’s water tank maintained the water level.

“I asked them, ‘How many of you have ever taken the lid off a toilet tank to see how it works?’” he recalled. “None of them had. How do you get to M.I.T. without having ever looked inside a toilet tank?”"

This is really surprising. Then again, this is not the first time I've glimpsed the possibility that attendnce at a prestigious school is a very noisy signal.

There was a generation of engineering professors at MIT (and I'm sure elsewhere) like Forrester, Doc Edgerton, Doc Draper, etc. who represented a sort of hands on experimentation who I suspect would not have become faculty in a later era. Which I consider rather unfortunate.

I remember that! I had the pleasure of being asked that very question by Professor Forrester around 1990. (though I could answer in the affirmative).

It's a bit les surprising if you realise professor Forrester taught at the MIT Sloan school, which is the Business School. A fairly large percentage of the B-school students at MIT have an engineering background so it's still surprising they didn't know what the inside of a toilet's tank looks like.

I was in one of his classes and it was one of the best courses I ever had. Understanding of system dynamics has turned out to be surprisingly useful in lots of aspects of my career, not just engineering. Professor Forrester thought it might be good to teach it in Kindergarten, and I've come to realise that is not as crazy as it sounds.

more memorably (ha ha you'll see what I did there) for the majority of people here, Jay Forrester invented core memory which revolutionized computers of that generation. Prior to core, memory schemes were bizarre and klugy, like storing information on the screen of a cathode ray tube, detectable when you scan across it again; or sonic vibrations in mercury which you wait to emerge from the other end.

Primary memory is still called core by old timers.

https://en.wikipedia.org/wiki/Magnetic-core_memory

>Primary memory is still called core by old timers.

Plus we still call them core dumps and have .core files

As well as basically the way we still design and build computers to this day.

In the one talk of his I attended, he said he switched to modeling because after he'd finished Whirlwind, he (and his team) had solved all the significant outstanding problems in computer design. And that's not an exaggeration, read this excellent book for the details: https://www.amazon.com/Project-Whirlwind-History-Pioneer-Com...

A great book by one of his proteges, Donella Meadows: https://www.amazon.com/Thinking-Systems-Donella-H-Meadows/dp...

This book changed my life. After reading this, I had an insatiable need to learn more about systems and dynamic systems interactions - a passion that led me to getting my macroeconomics degree today.

People used his models without understanding the mathematical solutions. Most of his models had links with first order difference equations with exponential solutions. Hence most factors went to infinity or zero if you ran then long enough. Worse was the Club of Rome projections which predicted the end of civilization by year 2000.

Forrester was himself very involved in the Meadows report. Forrester wrote "World dynamics" which is the system dynamics basis for the Meadows report.

https://en.wikipedia.org/wiki/World3

I learned recently that Will Wright was apparently influenced by Forrester and it lead to the creation of SimCity. Here a cool article about it. http://www.filfre.net/2016/06/simcity-part-1-will-wrights-ci...

It's not uncommon for influential scientists in different fields to have similar names, but when I was a student I was astonished that there were several with the unusual (to me) name "Jay Forrester". Eventually I figured out that they were all the same person!

If you have not stumbled upon DYNAMO before it is quentesential forrester https://en.m.wikipedia.org/wiki/DYNAMO_(programming_language...

If you want some context on the significance and influence of his work modeling systems through the concept of feedback loops, I recommend the second part of Adam Curtis' "All watched over by machines of loving grace":

"The use and abuse of vegetational concepts" https://vimeo.com/groups/96331/videos/80799352

Jump to minute 6:00 to watch the part about Jay Forrester, including an interview with him.

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