
The Dornier DO-960 Analog Computer - quakeguy
http://www.vaxman.de/my_machines/dornier/do960/do960.html
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pavlov
An artist named John Whitney made the world's first computer motion graphics
in the 1950s using an analog computer that was converted from a WWII anti-
aircraft gun control system. The results looked like this:

[https://youtu.be/TbV7loKp69s](https://youtu.be/TbV7loKp69s)

In the 1960s IBM hired him to work on digital computer animation concepts, and
he gave up on the analog system. But it's interesting how the technical
complexity of the work dipped for years while he had to wait for IBM's
general-purpose digital systems to catch up with the capabilities of the
analog computer setup.

~~~
jordanb
I read a book[0] a few years ago that spends some time on the rise and fall of
analog computing. Of course in the early electrical computer era it was not
obvious that digital computing would be the best way forward.

Digital modeling is a pretty block-headed way to go about building a
simulation. And when computers were slow and tubes and memory were very
expensive it seemed even more block-headed. The main advantage was flexibility
so as digital computers got faster and cheaper they ate more and more domains
where analog computers might have seemed more ideally suited.

[0] [https://www.amazon.com/Universal-History-Computing-
Quantum-C...](https://www.amazon.com/Universal-History-Computing-Quantum-
Computer/dp/0471441473)

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quakeguy
Linking the manual:
[https://drive.google.com/file/d/0B7h4vPhh2vD2SlY1OUdmNkFGRzQ...](https://drive.google.com/file/d/0B7h4vPhh2vD2SlY1OUdmNkFGRzQ/view?usp=sharing)
Sadly only in german.

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hengheng
I love German engineering jargon. They (correctly) wrote Moduln instead of
'Module' that is so common nowadays. Mutterplatine feels forced but I'll let
it pass. Some words for which there are no direct equivalents they took from
English (like Strobe), some are just as bad and contrived as the English word
(Aussprung for Escape).

~~~
quakeguy
Motherboard - Mutterbrett is ok i'd say, even Platine goes well.

~~~
blkhawk
I think "Hauptplatine" is the most common parlance - Just as
mainboard/motherboard is somewat exchangeable in english.

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dom0
His entire site is really quite interesting, almost strange that I never
stumbled over it (given a large overlap of interests).

Thanks for posting this!

~~~
2sk21
I agree - I love reading about how the guys are able to bring ancient
computers back to life.

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vasili111
Is there any type of calculations in which analog computer can outperform
modern digital computer?

~~~
nickpsecurity
Analog computers perform a few, specific operations at full-speed that take
quite a few components to do in digital with them only running at a specific,
clock rate. Combining them with digital computers that feed them problems and
measure the answers can be quite powerful. See especially the math-coprocessor
at first link. The neural simulation at second is illustrative where one wafer
(300+ chips) of analog NN's took 294,912 cores to simulate. That's full-
custom, high-end digital stuff rather than the average stuff. Analog also gets
used a lot in mixed-signal ASIC's where specific things are cheaper or lower
power per unit in analog so they mix digital and analog.

[https://www.schneier.com/blog/archives/2015/07/friday_squid_...](https://www.schneier.com/blog/archives/2015/07/friday_squid_bl_488.html#c6701962)

[https://news.ycombinator.com/item?id=11731697](https://news.ycombinator.com/item?id=11731697)

EDIT to add: The paper below is a short history of them that gives examples
whose benefits are consistent with other stuff I linked to. Some really cool
stuff there, too. :)

[http://oro.open.ac.uk/5795/1/bletchley_paper.pdf](http://oro.open.ac.uk/5795/1/bletchley_paper.pdf)

~~~
Animats
The question is the level of simulation. It's common to use a large number of
computers to run a VLSI simulation before fabbing a chip. NVidia has been
known to use 50 racks of 1U servers to run a gate-level simulation of a CPU.
The machines are running C code generated from VHDL. You could do the job of
the GPU with far less CPU power; a gate level simulation is executing multiple
instructions for each bit transition in a gate.

~~~
nickpsecurity
The level of detail is part of it. The inherent speed of analog on a large
range of numbers is the other part. I recall early efforts to model analog
circuits like digital gates overwhelmed the computer. One circuit with 9
transistors took over 50,000 equations or something to check. It just did that
much.

This is only true when they're doing the things they directly implement like
filters or differential equations. They run faster at fraction of size and
power.

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smoyer
Very cool project!

"I am quite desperately looking for an EPROM programmer capable of reading and
writing 2708 type EPROMs since I am afraid that the 2708 EPROMs on this board
will loose their contents - the are already about 20 years old."

It's not very hard to build your own programmer/verifier (reader) ... if you
can't find schematics then message me. But this is __very __important. Those
EPROMs are are erased by shining UV light through the window in the package
... get some UV opaque material over those windows immediately and stop
leaving them in the light.

In the mean-time, I'll dig around in my basement and see if I still have the
correct programmer for that part (I vaguely remember using it to restore my
COSMAC ELF to operation).

~~~
alexandrerond
it's from 2005...

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quakeguy
What's your point again? Said mainframe is from the 70ies.

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ThomaszKrueger
I used EAI's analog computers when getting my EE bachelors degree. It was
quite interesting, we even had a hybrid model that the professors were
scratching their heads to make it work, but the purely analog was great to
simulate integrals and such.

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perilunar
Not to be confused with the Dornier Do 217 'flying pencil'. Then I RTFA and
learned they are the same company!

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mrfusion
How can an analog computer do logic?

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dom0
Fuzzy logic for one thing, but usually you do not user analogue computers for
digital tasks, since that's a very inefficient use of their capabilities.
Instead, they can be used to directly calculate differential and integral
equations, "simulate" analogue filters of all kinds and so on. This works by
recreating the system in question using analogue integrators, differentiators
, amplifiers, log converters etc.

Input variables and output variables become voltages.

This is very different from digital, quantified computers. It's also extremely
useful, because a whole lot of things can be described by differential
equations, and since analogue computers have no FLOPS limit, but only noise
(also dynamic range) and bandwidth limits.

PS: There were also mechanical analogue computers (using gears but also more
complex constructions) and hydraulics based computers (but I think these were
not used practically, just for demonstration).

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david-given
Eevblog has a teardown of the mechanical analogue computer that drove an
astrocompass from a B52 bomber:

[https://www.youtube.com/watch?v=hzGaO4Kdz2Y](https://www.youtube.com/watch?v=hzGaO4Kdz2Y)

So, so many beautiful cams and moving arms...

