My favorite "lost" type of computer is the balanced ternary machines. These were actually built in the Soviet Union in the 1960s:<p><a href="https://dev.to/buntine/the-balanced-ternary-machines-of-soviet-russia" rel="nofollow">https://dev.to/buntine/the-balanced-ternary-machines-of-sovi...</a><p>Programming with trits and trytes!<p>Unfortunately, domestic Soviet computers were effectively killed by a 1970 decision to base all future efforts on a "Unified System" which was really a clone of IBM System/360:
<a href="https://en.wikipedia.org/wiki/ES_EVM" rel="nofollow">https://en.wikipedia.org/wiki/ES_EVM</a><p>Playing it safe by shooting yourself in the head...
Wow... the writing, the prose... wish I could put words together like that.<p>Sample:<p>""" Fame is partial with her favor, and has not seen fit to bestow any upon the creators of the panel switch, the type E relay, the crossbar marker circuit. There are no biographical anecdotes we can summon to illuminate the lives of these men; the only readily available remains of their lives are the stark fossils of the machines they created.
"""
You had electronic relays?<p>Finland had strong import controls directly after the war, so imported electronics was very expensive. Industry automation still used legacy hydraulic logic (fluidic logic) to control complex automation in pulp mill processes in 70's. It was very steampunk.<p><a href="https://en.wikipedia.org/wiki/Fluidics" rel="nofollow">https://en.wikipedia.org/wiki/Fluidics</a><p>Hydraulic logic control is still a useful thing but nobody builds complex industry automation using them.<p><a href="http://ph.parker.com/us/17567/en/hydraulic-logic-element-valves-hcd" rel="nofollow">http://ph.parker.com/us/17567/en/hydraulic-logic-element-val...</a><p><a href="http://www.logichyd.com/" rel="nofollow">http://www.logichyd.com/</a>
Today, hobbyists build these computer for fun and to test their engineering mettle:<p><a href="http://www.nablaman.com/relay/" rel="nofollow">http://www.nablaman.com/relay/</a>
<a href="http://web.cecs.pdx.edu/~harry/Relay/" rel="nofollow">http://web.cecs.pdx.edu/~harry/Relay/</a>
I accidentally discovered a year or so ago that Thomas L. Dimond (working at Bell) invented core rope memory (which the wikipedia page says was "first used in the 1960s") in the 1940s. His memory got used in phone switches as a fast and reliable read-only lookup table. Here is a paper about the "Dimond ring translator": <a href="http://etler.com/docs/Crossbar/articles/30-AMATranslator.pdf" rel="nofollow">http://etler.com/docs/Crossbar/articles/30-AMATranslator.pdf</a>
This book contains descriptions of many of these, including a particularly nice discussion of the Zuse Z3:<p><a href="https://mitpress.mit.edu/books/first-computers" rel="nofollow">https://mitpress.mit.edu/books/first-computers</a><p>Also here: <a href="http://www.inf.fu-berlin.de/lehre/SS01/hc/zuse/node4.html" rel="nofollow">http://www.inf.fu-berlin.de/lehre/SS01/hc/zuse/node4.html</a><p>Interestingly, the machine (built in 1941) used binary floating point. (Not IEEE754. :-))
I worked on a project that replaced an electromechanical Telex switch. Four racks of microcomputer based hardware replaced an entire floor of mechanical relays.<p>However it was a marvel to see and hear that thing click and clack all day, with technicians with their ear trained to detect issues and replace relays by listening to the switch.<p>Of course billing was done through a guy on top of a ladder taking large format B&W pictures of the bank of user's (mechanical) counters.
Even though I only scanned the article, many of those computers appear in Turing's cathedral G.Dyson[1], book which I enjoyed, given that there is not a lot of history lessons at the universities (at least the one I went to in Buenos Aires... UBA).<p>[1] <a href="https://openlibrary.org/search?isbn=0375422773" rel="nofollow">https://openlibrary.org/search?isbn=0375422773</a>
If this interests you, I've got to throw in a plug for the Museum of Communications in Seattle. They've got a bunch of old mechanical telephone switches running. There's something truly awesome -- in the correct sense of the word -- to be standing inside a computer and hearing the signals passing around you. It is a unique experience that I strongly recommend.
I built a relay computer for a science fair in the 60's. The power supply was from a pinball machine. The relays were mercury-sealed, from an aircraft.<p>It had seven words of five bits each (that's all the relays we had). It could add, subtract and store results.<p>We got honourable mention.
Yann Guidon made a nice little relay computer on hackaday.io<p><a href="https://hackaday.io/project/18757-ygrec16-ygs-16bits-relay-electric-computer" rel="nofollow">https://hackaday.io/project/18757-ygrec16-ygs-16bits-relay-e...</a><p>Enjoy
Fascinating read, especially The part about Bell Model III.
The machine had lookup tables, which were actually tab-separated paper. It was an actual table. They further implemented in the functionality to jump forward and backward in that table (they called it "hunting").<p>I don't have much experience in assembly, but reading this article made me appreciate it more. Assembly basically operates with the same principles as the first computers.
There's another kind of "lost" computer that many don't know about. Actually, I hesitate to call it a computer, as it didn't compute anything, and none of the actual machines had anything like a conditional branch operation that I am aware of...<p>...they're called "reproducing pianos" (also "reproducing player pianos" and "reproducers"). Not many were manufactured, due to their complexity, need for a lot of maintenance, and sheer cost.<p>Basically, they were a kind of player piano that strived to reproduce the actual mechanics and technique of the person who "recorded" the original paper roll. They did this by having additional tracks which handled certain nuances of the player and such, such that when the roll was played back, the piano could play in the same manner.<p>These player pianos were much more mechanically sophisticated than regular player pianos, and those extra tracks acted like a form of control structure for the notes being played. I believe that on some of the models meant for public performances, you could select the song (and it would "wind" itself to the song, sensing when it had located the piece), and I think they also had an auto-rewind function - but that was about the limit of their operations.<p>I've always thought of a CPU - in it's simplest form - as nothing more than a sophisticated and fast "player piano", with memory being the roll, the word at an address being the holes in the roll at a certain point, and the CPU being that which controlled the operations and were instructed by those same holes. This in fact was actually implemented in some early electronic computers (known as "drum-based" computers).<p>The history of computers and computation is a fascinatingly deep and varied field of study; I encourage everyone to delve into it a bit.
We built relay computers in HS in the early 60's. There was this street in London: Lisle St, in the Soho district. One could buy surplus PO 3000 multi-pole relays there real cheap - up to 10 pole IIRC. These were the relay type used on the Post Office Telephone exchanges, pre-electronics (up to #5?). In 66 I also discovered a recently published book by Russian authors: "Introduction to the Theory of Finite Automata" by Trachtenbrot and Kobrinskji <a href="https://g.co/kgs/EqZYC2" rel="nofollow">https://g.co/kgs/EqZYC2</a> which taught me the formal of the topic using relay logic. I believe the robustness of Russian space tech was due to use of relays as well as tubes. That book gave me my career, effectively; turned out to be equally appropriate for electronic logic circuitry.
Wonderful read.<p>These types of articles always puts the amount of computing power I spend to watch videos of a cat jumping into a box and falling over into perspective.
Anyone who enjoys relay computers would probably find electromechanical pinball machines fascinating.<p>It's quite amazing what they accomplished with mechanical relays!