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A 1961 Relay Computer Running in the Browser

minivac.greg.technology

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Re: A 1961 Relay Computer Running in the Browser

#21

Post by JKCalhoun »

analog31 wrote: post #3
etaioinshrdlu wrote: post #2

"Before microchips existed, computers were built with mechanical relays." Should probably say something about vacuum tubes as well!

And discrete transistors. Now that my curiosity is piqued, I found this nice timeline: https://www.computerhistory.org/timeline/computers/ It looks like transistorized computers were dominant at the point when integrated circuits were introduced.

Interesting: the entry for the Apollo Guidance Computer (AGC) indicates it used integrated circuits—I had remembered hearing it used RTL (resistor-transistor logic).

It turns out both are true [1]. The "integrated circuits" were sort of "flat-packs" of RTL circuits. I had forgotten that early IC's were not quite what we envision today. Regardless I suppose ICs were RTL before they were TTL (before they were CMOS, etc.).

[1] https://en.wikipedia.org/wiki/Apollo_Guidance_Computer#Logic...

Re: A 1961 Relay Computer Running in the Browser

#22

Post by JKCalhoun »

analog31 wrote: post #7
hbrav wrote: post #4

Earlier quoted context omitted.

And before that with gears! (With limited success.)

Indeed, my dad was a research scientist at a large chemical company, and every scientist had a Friden mechanical calculator, which was capable of multiplying and dividing. But it was not a programmable computer. When the HP 35 came out, it was cheaper than the annual maintenance contract for the Friden. They bought one, and passed it around to try out for a week, then all of the Fridens went into the dumpster. Of cou…

Ha ha, the rich kids when I was in high school Physics had these calculators. It was the first I had seen them. At over $100 (as I recall) they were completely out of reach for me and half the class.

(Ands they had to either have an extra set of batteries handy or access to an outlet to plug in the cord since the possibility of the batteries dying during a test was a real likelihood.)

Re: A 1961 Relay Computer Running in the Browser

#23

Post by JKCalhoun »

ljsprague wrote: post #6

I imagine it would be easier for me to build the simulator than to make it do anything of interest.

While snarky, I see where you're coming from. Sometimes a lot of the fun is in the building of a thing to understand how it works. Learning how a thing works from the user-facing side of the control panel is, for some of us, less rewarding.

If anything though, I want to go build a physical relay computer mechanism myself now (if even just a 4-bit adder or something).

Re: A 1961 Relay Computer Running in the Browser

#25

Post by gregsadetsky »

JKCalhoun wrote: post #20
gregsadetsky wrote: post #9

Thank you so much everyone, this is something I've worked on for a few years on and off -- I posted about it here in a Show HN a few hours ago [0] The biggest unlock was finding Willy McAllister's excellent Circuit Sandbox [1], which provides the Minivac Simulator's underlying electrical math. I tried so many approaches to simulate electricity (a doomed DIY approach, Falstad, Spice...) but Circuit Sandbox's DC analys…

Super cool. And thanks for links to the original manuals for those that want to take a deep dive. Feature request: I was wanting for a bit more sound… I mean, when I see "relay computer", I'm heading there for lots of soft clicks.

More…?! :)

I totally feel you - the one reservation is that I’m using (gasp) not the original Minivac Relay sound. I need to go to a Computer Museum that will let me record one to offer a more authentic simulated experience.

So tldr - let me get a clean real sound and then we can come back to this question :)

Re: A 1961 Relay Computer Running in the Browser

#26

Post by gregsadetsky »

bolangi wrote: post #24

Here's a demonstration of a 1958 relay computer. https://youtu.be/_j544ELauus?t=373

Thanks!

The Enigma-cracking Bombe (on display at the extraordinary Bletchley Museum of Computing) also used relays

https://www.tnmoc.org/bh-10-bombe-description

And the Z3 as well!

https://en.wikipedia.org/wiki/Z3_(computer)

Re: A 1961 Relay Computer Running in the Browser

#28

Post by gregsadetsky »

anonzzzies wrote: post #17

Ah yes, I have a stack of these; lovely things for kids to learn some basic stuff. They are the oldest systems I own and they still work (they are fairly easy to fix).

Amazing! I don’t think I’ve heard of anyone owning many..!

1) Are any of them for sale? :)

2) Would you be open to recording a clean sound of one of its relays turning on and off? And helping me figure out some specifics about the motor wheel (its speed and whether it experiences any speed up)

Thank you! My email is:

hi at greg.technology

Re: A 1961 Relay Computer Running in the Browser

#29

Post by vipvip »

analog31 wrote: post #7
hbrav wrote: post #4

Earlier quoted context omitted.

And before that with gears! (With limited success.)

Indeed, my dad was a research scientist at a large chemical company, and every scientist had a Friden mechanical calculator, which was capable of multiplying and dividing. But it was not a programmable computer. When the HP 35 came out, it was cheaper than the annual maintenance contract for the Friden. They bought one, and passed it around to try out for a week, then all of the Fridens went into the dumpster. Of cou…

[dead]

Re: A 1961 Relay Computer Running in the Browser

#30

Post by anonzzzies »

gregsadetsky wrote: post #28
anonzzzies wrote: post #17

Ah yes, I have a stack of these; lovely things for kids to learn some basic stuff. They are the oldest systems I own and they still work (they are fairly easy to fix).

Amazing! I don’t think I’ve heard of anyone owning many..! 1) Are any of them for sale? :) 2) Would you be open to recording a clean sound of one of its relays turning on and off? And helping me figure out some specifics about the motor wheel (its speed and whether it experiences any speed up) Thank you! My email is: hi at greg.technology

I am currently on vacation, but when back I will contact you.
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