
4 bit computer built from discrete transistors - danielam
https://hackaday.io/project/665-4-bit-computer-built-from-discrete-transistors
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bashinator
I always like to point out the telegraph relay computer[0] built by one Harry
Porter. I think that pretty much takes the cake for retro hardware. It also
brings up the question of how early a binary computer could have been built,
since the relay was invented in the early/mid 1800s[1] and Boolean logic in
1847[2]

[0]
[https://www.youtube.com/watch?v=n3wPBcmSb2U](https://www.youtube.com/watch?v=n3wPBcmSb2U)
[1]
[https://en.wikipedia.org/wiki/Relay#History](https://en.wikipedia.org/wiki/Relay#History)
[2]
[https://en.wikipedia.org/wiki/George_Boole#Symbolic_logic](https://en.wikipedia.org/wiki/George_Boole#Symbolic_logic)

~~~
TheOtherHobbes
For some reason it took 90 years for Boolean switched hardware to appear -
originally invented by Shannon in the US and Zuse in Germany in the late
1930s.

It's interesting to wonder why it took so long, and what would have happened
if it had been invented much earlier.

The first may have been because Boolean algebra was very obscure and unlikely
to cross the path of the electromechanical and telegraph engineers who worked
with relays.

The second I can't even begin to speculate about - although the first FET was
patented in 1925, so in theory it would have been possible to build a solid
state computer not long after.

~~~
13of40
Let me don my tinfoil hat and say that one of the major functions of a
computer back then was fire control for artillery, later seconded only by
cracking Axis encryption. Maybe anyone who tried to source 10,000 reliable
relays in 1938 got a knock on their door...

[tinfoil hat off]

~~~
cpayne
I don't think that is as crazy as it sounds. Remember, back then, the
commercial potential of a "computer" was for the military.

Even if you had the idea & concept back then, AND the money to build it - what
would you do with it? You're not using it like we use computers today...

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MarcScott
I went to see this 16 bit processor a few months ago. It's stunning to see.
[http://www.megaprocessor.com/index.html](http://www.megaprocessor.com/index.html)

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kuschku
I’d like to point out that this is common at many universities for compsci
undergrad students as 2nd-year project (although usually done simulated in
Xilinx ISE and ISim).

It’s definitely interesting to do these things (I’m currently taking
abovementioned course at my uni, designing first a 4-bit harvard architecture
processor in Xilinx, and, after that’s done, in 2 weeks starting with
designing a DLX in Xilinx), but it’s even more amazing to see someone actually
build these things IRL (and thereby prove that these are actually useful
skills to have!)

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tdeck
If you like this, you might appreciate the very retro homebrew CPU webring:

[http://members.iinet.net.au/~daveb/simplex/ringhome.html](http://members.iinet.net.au/~daveb/simplex/ringhome.html)

~~~
bashinator
Yep, that's the ring Harry Porter is on.

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toomanythings2
I used to design and build whole systems from TTL logic in the 70s and 80s.
The most integrated part was the ALU from AMD, otherwise, it was mostly NAND
and NOR gates. Great fun, especially cause we knew how everything worked.

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userbinator
Just recently there was another project building processors with discretes, a
6502:
[https://news.ycombinator.com/item?id=11703596](https://news.ycombinator.com/item?id=11703596)

