
Harvard Mark I - angrygoat
https://en.wikipedia.org/wiki/Harvard_Mark_I
======
williamstein
A fun thing about this computer is that you see it (for free) every time
you're in the Science Center at Harvard. You don't have to go to some special
museum.

~~~
sandworm101
But it wasn't actually a computer. It was technically just a calculator. The
way it was designed meant that it was not the Turing-complete and/or von
Neutmann-type machine that we now describe as a computer. It did some things
very very well, but was not a general purpose machine capable of running any
program asked of it.

~~~
commandlinefan
Well, it was still more than a calculator, since it was programmable: a
calculator can add or subtract, but can't be instructed to do one and then the
other without human intervention.

~~~
sandworm101
Yes and no. It is a programmable calculator, but it cannot run an unending
program. It doesn't have the "go to X" functionality to bounce back and forth
along a long tape of instructions. It can run a sequence of tasks, much like a
player piano can, but eventually gets to the end of the program and is
therefore limited. A proper computer can calculate anything. It might take
trillions of years to complete some tasks, but a proper "computer" can run
programs with no defined end. Calculators can only run sequences.

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dmix
If only WW2 lasted another 5yrs I'm curious what else would have been
accomplished in that timeframe. They were all just starting to perfect some
advanced technology.

The motivation from people dying and patrotic goals, combined with budget (but
a constrained one) and every person in the country attempting to contribute to
the effort seems like a good recipe for new technology development. Especially
for finding the stuff that will actually do something useful today and not in
10yrs, since it was already needed yesterday.

Obviously the costs of the war outplay the value from this but it's
interesting to think about.

~~~
crimsonalucard
There are other alternative paths of technology that we could've went down. A
turing machine is isomorphic to lambda calculus and possibly isomorphic to
many other machines.

Like how javascript is an arbitrary way to do frontend programming, it's
possible the current computing paradigm is also arbitrary.

~~~
Ididntdothis
“it's possible the current computing paradigm is also arbitrary.”

I think that’s true. Makes me wonder how things would look if you redesigned
things with today’s knowledge if you didn’t have to worry about existing
infrastructure.

~~~
crimsonalucard
Not just that. Arbitrary choices are made at every level of computing from
even logic below the turing machine all the way up to javascript for browsers.

Imagine if they decided to use 3 voltages to represent numbers. Instead of 3.5
volts for 1 and 0 volts for 0 what if we had a trinary representation 5 volts
for 2, 3.5 for 1 and 0 volts for 0.

Or what if analog computing took off instead. Instead of trying to make
everything digital we built machines that are functions of analog voltage
waveforms and poured all of our abilities into reducing noise instead of
upping clock speed.

Is the technology we use now the result of arbitrary choices made out of pure
luck or given enough time all civilizations will develop digital computing due
to inherit limitations of the physical world.

~~~
nradov
No need that imagine. Ternary computers have been built. They do work but are
less practical than binary.

[https://en.m.wikipedia.org/wiki/Ternary_computer](https://en.m.wikipedia.org/wiki/Ternary_computer)

~~~
Ididntdothis
Question is : are they really less practical or have we just put a lot of
effort into binary and with the same effort ternary would be better?

~~~
jdsully
The beauty of digital is you are avoiding the “linear” portion of transistors
and are always running them saturated. A ternary machine would require running
the transistors in the linear region - which ultra small transistors are
terrible at.

There are alternative designs using +/0/\- saturated signaling but those have
higher voltages and larger transistor counts.

I’ve played around with linear designs which can indeed use fewer parts but
you need high quality transistors and they’d still be slow.
[https://hackaday.io/project/3628-trinity/log/11995-2-transis...](https://hackaday.io/project/3628-trinity/log/11995-2-transistor-
carry-function)

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elipsey
TIL "patch" and "loop" didn't used to be metaphorical -- they did it
physically with punch card tape!

Also, that has to be the classiest enclosure ever made. Check out some of the
designer's other work:
[https://en.wikipedia.org/wiki/Norman_Bel_Geddes](https://en.wikipedia.org/wiki/Norman_Bel_Geddes)

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dmix
> After two rejections,[4] he was shown a demonstration set that Charles
> Babbage’s son had given to Harvard University 70 years earlier. This led him
> to study Babbage and to add references of the Analytical Engine to his
> proposal

It's amazing how old rediscovering old ideas can create scientific/technology
revolutions.

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cpr
This was in the lobby of the old Aiken Computing Center my undergrad years,
but moved out when they built the new "cheese wedge" Gates/Ballmer building on
the same spot.

Always entertaining to walk by and see the "bugs" (moths) in the (then already
defunct) relays...

