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City And/Or Photo As CPU

A city which works as a CPU whose photo can also work as such
  [vote for,

It's a cliche that PCB and microprocessors look like aerial views of cities, so this has that issue, but I hope I've done something new with it.

Design a city with enormously wide power cables clearly visible from the air along with junctions to those power cables which work as relays or storage capacitors, the former wired together in such a way as to implement logic gates. The top surface of everything in the city is painted with contrasting paint and a literal outline of a component which if realised in conductor plus insulator form would work as the component it actually contains.

The components are buildings with continuous stripes of contrasting colour down their walls which glow in the dark or not according to whether they are insulators or conductors. These join directly into an underslung monorail transit system which is similarly painted on top accordingly.

The entire city works as a CPU which happens to implement a program which controls various aspects of the city such as transport, utilities, stock control and logistics.

At night, the city lights up in strips rather than the usual street lighting. This enables it to be photographed aerially using old-fashioned silver compound emulsion type techniques. If the photograph is then processed in the right way, it will become a functional network of silver wires on a plate which will itself function as an identical CPU to the city itself.

There are a number of problems with this:

* I've been vague about the nature of the contrasting colours. I've mentioned glowing, street lighting and so forth, and I don't like that I've done that because it's made it too vague.

* I'm not sure whether a method really exists whereby a photographic emulsion can be completely converted to metal plus insulating gaps. I do, however, think the surface of the emulsion should be glassy rather than crystalline.

* Only one layer of circuitry is possible, unlike a conventional microprocessor.

* I'm not at all sure if silver in particular or any single layer of metal can be used to realise electronic components. I'm more or less confident it can be used to make capacitors but the rest seems a bit implausible. In particular relays, valves and transistors are all ruled out because there are no moving parts, no evacuation, no ferromagnetism and no semiconductors. Having said that, I wonder if a photography technique could be developed that deposits semiconductors, or whether that actually exists in the form of however they make chips.

nineteenthly, Jan 26 2017

Home, sweet home ... http://cdn.wallpape...om/51/31/Q8DVba.jpg
Baked and WKTE ... [8th of 7, Jan 26 2017]

A good article, includes the bit about how AMD made the 9080 http://silicongenes...nscripts/hailey.htm
…search for the first occurrence of 'xerox' and read onward a few paragraphs. [Ian Tindale, Jan 26 2017]

Electron flow in transistors http://www.faqs.org...ic/Semi/SEMI_4.html
Go to the third diagram, see how the electron flow is for NPN and PNP transistors. [Ian Tindale, Jan 26 2017]



8th of 7, Jan 26 2017

       Yes, [8th], very pretty.   

       But we all know that the Borg cube is only a gigantic Rubik's Cube, accidentally manufactured with 1km sides due to a decimal point error when placing the online order through Shapeways. Just because you've peeled the stickers off doesn't make it clever, though it is big.
MaxwellBuchanan, Jan 26 2017

       Not to counteract anything you've said, but I'd add a few thoughts:   

       Start with something that isn't a microprocessor. Microprocessors are wonderfully functional things, all in one slab, but there's examples of other equally wonderful integrations that aren't so big and yet are just as much fun. I'd suggest something like the 555. In fact, not something like it, I'd suggest it. It's smaller, easier to understand, and yet contains a packet of tools that enable some fairly definite functions and behaviours to happen. The 555 is also very well understood and a fundamental block that is used in teaching and actual industry even to this day (although in actual use, the 7555 cmos version is preferable, as it doesn't slam the power lines so brutally upon output excursions).   

       There is a method of converting photographic emulsion to conductor and insulator patterns, because indeed all actual chips and even microprocessors start their life as a photographic film image. Indeed, AMD when they were beginning out had to hand retouch the negatives of the cpu they were working on, which contained errors in the repro process. I'll post some links on the early days of AMD and their 9080 copy of the Intel 8080 made from piecing together photographs of the silicon die and redrawing it back to the circuit. But yes, the die starts off as a negative film (line film), and in those days, full of pinholes.   

       Semiconductors should be able to be created simply by making an 'in between' between a conductor and insulator. To a certain extent, a resistor is that, but what we generally mean by a semiconductor also incorporates directionality, hence a diode allows greater electron flow in one direction than another (and a transistor (which can be thought of as two back to back diodes, because it is a three layer sandwich of the two doping polarities) acts as a kind of lever whereby the flow through two ends is contingent on the level of energy on the middle connection). So, you'd need not necessarily a semiconductor (which is just the way we do it now, valves were not semiconductors) but rather, you'd need the functional urban equivalent of a diode.   

       The other advantage of a 555 rather than a full cpu is that you could do it on the scale of a village, or a town, rather than a whole city.
Ian Tindale, Jan 26 2017

       // you'd need the functional urban equivalent of a diode //   

       It's called the Chiswick Flyover on the North Circular, and unfortunately it's Baked and WKTE.
8th of 7, Jan 26 2017

       The Hogarth Roundabout flyover on the A4 is more closely equivalent to a diode, surely?
hippo, Jan 26 2017

       Well, are there any traffic systems that exhibit a behaviour of a maximum flow from one end to the other, but regulated by a flow into a middle? (Or out of, in the case of NPN) (see page I've linked to here, no, not here, up there elsewhere, somewhere).
Ian Tindale, Jan 26 2017

       Actually, I just thought - a severe road traffic accident in the opposite lane of a motorway has the effect of retarding flow in the unaccidented lane as people slow down and think about things for a while. This is essentially a field effect, the accident is the gate exhibiting a field effect on the flow between source and drain of a single doped layer, as a normal FET is.
Ian Tindale, Jan 26 2017

       And also, hippo, bicycles.
Ian Tindale, Jan 26 2017

       Processor speed tends to go down as size increases, due to the time it takes signals to travel from one part of the CPU to other parts. A CPU as large as a city might be too slow to handle the real-time city-data processing that was suggested in this Idea
Vernon, Jan 26 2017

       //Only one layer of circuitry is possible//   

       Subways? Flyovers?   

       Also <placeholder for bus-related pun>
MaxwellBuchanan, Jan 26 2017

       It would be problematic to take a photo of a subway from the air.   

       I thought about clock speed and decided it should be asynchronous, but yes, it might be slow.
nineteenthly, Jan 26 2017

       Synchronicity is overrated. Once we develop proper computers it will be seen as a very strange idea.
MaxwellBuchanan, Jan 26 2017


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