back to article This whopping 16-bit computer processor is being built by hand, transistor by transistor

A bloke in Cambridge, UK, is building a computer processor using 14,000 individual transistors and 3,500 LEDs – all by hand, piece by piece. James Newman said his Mega Processor relies almost entirely on the hand-soldered components, and will ultimately demonstrate how data travels through and is processed in a simple CPU core …

  1. Steve Crook
    Thumb Up

    Completely and utterly bonkers

    But I hope he manages to complete it and find a home for it because it'll be a wonderful achievement.

    I'm assuming it'll go abroad because that's where most great British technology ends up...

    1. Martin Taylor 1

      Re: Completely and utterly bonkers

      Doesn't have to go abroad, bring it to the Museum of Computing in Swindon if they have space (it's almost abroad, I guess, from a Cambridge perspective). It may not be truly a museum piece yet, but it's undeniably a brilliant educational tool.

      We have good beer, too.

      1. Spiracle

        Re: Completely and utterly bonkers

        If they'll take it in at the Cambridge museum he'll be able to throw a couple of spools of solder into his bike basket and cycle down to finish (or, more likely, mend) it.

        1. TRT Silver badge

          Re: Completely and utterly bonkers

          It could also find a home as the set of some homage Sci-Fi production, along the lines of Space:1999. Now that was a computer with a lot of lights!

          1. Anonymous Custard Silver badge
            Thumb Up

            Re: Completely and utterly bonkers

            Given some of the stuff they put in there, he could probably get a room in the Tate Modern for it for a while too.

            Wonderful stuff anyway, hope it doesn't drive him too crazy getting it finished and debugged.

      2. This post has been deleted by its author

    2. Steve Crook

      Re: Completely and utterly bonkers

      If you haven't, go and look at the WEB site for the project. It's fascinating, board construction, component layout, testing, managing connections. Amazing breadth of skills the man has.

      From his site:

      "I spent a bit of time trying to work out how to do the 7-segment display using discrete transistors but the answer is vast. Really, really big. It would have near doubled the size of the thing and the circuitry for the display would have obscured the circuitry for the processor which would have undermined what I was trying to do. As its only for debug and not proper function I went for chips. This is definitely NOT cheating, it is just for debug. It is irritating though."

      And

      "The RAM's turning out to be quite sizable. A square inch per bit ! I'm hoping to do 64 bytes, but that translates to the best part of two square metres."

      Really, I had to laugh. Sizeable? Not half it isn't.

      1. bonkers

        Re: Completely and utterly bonkers

        As the final arbiter of all things Bonkers, I approve, wholeheartedly.

        I actually know the guy, we discussed this in the kitchen at work just a few months ago.

        I suggested he use these new "chip" things you can get.

        1. TRT Silver badge

          Re: Completely and utterly bonkers

          Imagine if he'd used valves...

          1. Roq D. Kasba

            Re: Completely and utterly bonkers

            Seems to me this would be a great project to distribute between many enthusiasts - lots of similar modules, so publish the schematics and a bill of parts, enthuse a bunch of others, and spend the time integrating :-)

          2. Fatman Silver badge
            Joke

            Re: Completely and utterly bonkers

            Imagine if he'd used valves...

            There are several examples of those monstrosities around.

            Here is a list:

            https://en.wikipedia.org/wiki/List_of_vacuum_tube_computers

            1. metasonix

              Re: Completely and utterly bonkers

              >There are several examples of those monstrosities around.

              None of which are actually functioning today. The Computer History Museum in California has a number of historic tube computers which would be a nightmare to restore to working order. Most of them used magnetic drum memories, guaranteed to be nonfunctional and almost impossible to repair. The only tube computer that is functional today is the Colossus replica at Bletchley Park, and it's not even a "general purpose" computing device.

              1. Phil Endecott Silver badge

                Re: Completely and utterly bonkers

                > None of which are actually functioning today.

                The Manchesterr "Baby" replica in the museum of science and industry is functional. Or was last time I visited.

              2. Chemist

                Re: Completely and utterly bonkers

                "None of which are actually functioning today"

                AFAIK the replica of the Manchester 'Baby' is around and ran in 1998. I was taught physics by a chapvwho worked on the original and had a photo of himself, stripped to the waist, working in basement surrounded by racking

      2. Phil O'Sophical Silver badge

        Re: Completely and utterly bonkers

        The RAM's turning out to be quite sizable. A square inch per bit !

        Sounds like he's using static RAM, maybe he should have tried a dynamic RAM design? With decent capacitor sizes he wouldn't have too fast a refresh cycle...

        I suppose core memory would be better still, if he's into knitting!

        1. elDog Silver badge

          Re: Completely and utterly bonkers

          The hum from those cores would be amazing. And to replace a burnt-out one? I remember the days when we "programmers" would write a loop to flip a bit on and off and get that one core very toasty red.

    3. Fortycoats

      Re: Completely and utterly bonkers

      Of course it's completely bonkers. It even has an "Igor" (4th module from the left in that basic mock-up diagram). No mad-scientist project is complete without an Igor.

      Yeth, marthter......

      Well done that man. Hope it works out.

    4. JeffyPoooh Silver badge
      Pint

      AN OUTRAGEOUS ERROR!!

      "...20,000 instructions per second from a 20KHz clock."

      The 'k' in kHz should be lowercase.

      Thanks.

      1. zhveurnq

        Re: AN OUTRAGEOUS ERROR!!

        It was bitflip, ociffer.

      2. Daniel von Asmuth Bronze badge

        Beat the clock

        I wonder what's keeping him from increasing the clock speed.

        1. Phil O'Sophical Silver badge

          Re: Beat the clock

          I wonder what's keeping him from increasing the clock speed.

          Propagation delays across those square metres of panels, I'd guess.

          1. adam 40

            Re: Beat the clock

            It's only 14m long. Assuming 0.7c because of the dielectric of the wires that would be 66.6ns propagation delay end-end. So you could run is under 15MHz, say 1MHz should be do-able.

            With the current speed it still beats the 1957 all-valve DASK.

            1. Charles Manning

              Re: Beat the clock

              It's the capacitance, not the length.

              Those wires act as huge capacitors which need to charge and discharge on each cycle to allow the signal to stabilise.

              1. Nigel 11

                Re: Beat the clock

                Those wires act as huge capacitors which need to charge and discharge on each cycle to allow the signal to stabilise.

                Not huge.

                The general rule for a signal to settle on a plain old wire is something like six times longer than the speed of light along the wire. (Or two to-and-fro bounces at 0.7c)

                I've often wondered what is the optimum design for a discrete-transistor computer. Minimise the transistor count, build as small as possible, and clock as fast as possible, or go for wider buses and more transistors clocking more slowly? (Of course in the early days they went for small component counts, because transistors - germanium alloy junction ones - were significantly expensive, and suffered thermal runaway at fairly low temperatures so cooling really mattered. )

            2. ChrisBedford

              Re: Beat the clock

              "It's only 14m long. Assuming 0.7c because of the dielectric of the wires that would be 66.6ns propagation delay end-end. So you could run it under 15MHz, say 1MHz should be do-able"

              Yeaaahhhh... I only know a tiny little bit about RF, so I might be talking complete rubbish here, but wouldn't there be radiation issues? I seem to remember that one of the constraints on the original IBM PC (4.77 MHz) was that pushing the clock any higher led to disproportionately high energy losses to radiation (and of course interference with your transistor radio!), and that on a printed circuit board of much less than 2 sq ft. I imagine that a 14m long assembly with lots of interconnecting cable and hand-soldered assemblies might have a slightly worse problem with that.

              1. Nigel 11

                Re: Beat the clock

                Take a look at a photo of an old enough computer that the CPU consisted of a large number of logic modules connected with a wire-wrapped backplane (for example Google "Images PDP-8 Backplane). You'll soon deduce that the interference problem is not insurmountable. It was not negligible, though!

                The routing of wires within the backplane was a black art. Some were artificially lengthened so as to introduce deliberate signal delays. Others took non-parallel routes from A to B to reduce crosstalk - interference is by far the greatest between closely parallel wires. The general term was "random-wired". It was most definitely not a good idea for structure in the circuit schematics to be explicit in the physical arrangement of wires in the backplane.

          2. Andrew Torrance

            Re: Beat the clock

            My final year university project was something similar , building a bit sliced processor . The limiting factor on speed for us was the capacitance and length of the cabling . I expect it will be similar for this guy .

            1. Michael H.F. Wilkinson Silver badge
              Pint

              Re: Beat the clock

              Maybe he is initially being conservative. I bet there is some room for overclocking this BRILLIANT piece of work that I am certainly going to feature in next year's "Introduction to Computing Science" course that I teach.

              1. Simon Harris Silver badge

                Re: Beat the clock

                He found out that a state transition takes about 1uS to propagate through a gate, and to work right through an adder was about 40uS (change on the LSB through to carry out) - it's this that sets the maximum clock frequency.

        2. picturethis
          Mushroom

          Re: Beat the clock

          To some degree it not just the length of the wires, but the differences in length wrt the frequency being used.

          I sure hope he's keeping the length of the wires (as appropriate) the same to each (and within) similar functional banks of transistors, otherwise the differing propagation delays will be madness to try to debug. This is normally done at chip layout and PCB layout. Clocking in incorrect bits (on some lines) and not others would surely lead to a long stay at a mental institution.

          Slowing down the frequency until it worked might be practical, but with a little attention to the lengths, he might find that he could run at a much higher frequency. Overclock - baby....

      3. Old Handle
        Joke

        Re: AN OUTRAGEOUS ERROR!!

        You're not familiar with Kelvin-Hertz? It's a measure of how much a computer heats up per cycle. Although at 20 Kelvin-Hertz this design does seem fairly impractical.

      4. jeffdyer

        Re: AN OUTRAGEOUS ERROR!!

        kHz or KHz is valid, after all, little "m" means "milli", big "M" means "mega", as kilo = 1000, it is a multiplier and can be K. But from wikipedia:

        * The engineer's society, IEEE, and most other sources prefer "kHz" to "KHz." This apparently makes it less likely that users will confuse "kilo" (decimal 1,000) with the computer "K" (1,024).

  2. Hans Neeson-Bumpsadese Silver badge
    Thumb Up

    Yes!

    In a world where school "IT" lessons revolve around how to use PowerPoint, *this* is exactly what we should be doing to show kids how proper IT works.

    1. Terry 6 Silver badge

      Re: Yes!

      Absolutely,

      I'm no fan of "coding" in schools.

      Which seems to be pretty pointless for most kids.

      But if we're showing the kids what is actually under the bonnet and then letting them try to make it do something there's a chance that some ( the right ones ) will be inspired to really get involved.

      1. hplasm Silver badge
        Thumb Up

        Re: Yes!

        I seem to remember a ladybird book ( I think) with a computer made from wood and OC71 germanium transistors, and some dairy/milk Co series* of many-how to booklets that did the same sort of thing.

        Where are these sort of things now...?

        *can't find them on Goog - they were thin, square and white, with blue titles etc.

        1. Hans Neeson-Bumpsadese Silver badge

          Re: Ladybird?

          Are you sure it was Ladybird. The content sounds like the sort of thing that used to be in MacMillan books (squarish format, white cover with thin orange/red border).

          Either that, or something out of Professor Branestawm perhaps

          1. J.G.Harston Silver badge

            Re: Ladybird?

            Project Books published by the Dairy Industry Council.

        2. Charles Manning

          Re: Yes!

          Was the wood + gerrmanium transistors not a book on radio? I have a copy of one of those.

          The "computer" I remember from one of these books was nothing more than a continuity-based wire game thing that buzzed or lit up when you connected 2 + 2 = to 4.

      2. Tocsin

        Re: Yes!

        Our maths teacher did this to us in 1971 - built on vero boards, 16x 8bit memory, accumulator, command register, counter and a few gates... after one or two attempts to do other things, I spent a (mostly) enjoyable career in IT ;)

        (I still have the manual!)

    2. Sgt_Oddball Silver badge

      Re: Yes!

      If it helps I remember managing to make a desk calculator (not this beasty but still) getting binary to work on a hardware level is not easy but really fun (for the geeky types anyways)

  3. Anonymous Coward
    Anonymous Coward

    Awesome! I cannot approve more of this project - what a geek, utterly awesome!

    Cambridge Uni: He mentions space is a problem for the final CPU, please promise this guy a room for a few months to demo the finished CPU - knowing this will surely aid his motivation.

    Funding: How much is this all costing? Where do I donate some transistors?

    1. A Non e-mouse Silver badge
      Pint

      Where do I donate some transistors?

      Transistors? Give the bloke beer. And lots of it.

      1. Anonymous Coward
        Anonymous Coward

        Maybe best to save the beer for when he's finished. :-)

    2. keithpeter
      Windows

      Sponsorship...

      Or sponsor a gate or two?

      1. TRT Silver badge

        Re: Sponsorship...

        They'll name them after you. I hear Bill has a few already.

  4. TedF

    The Fellow is a fraud! Commercially made transistors? Pah! Get some Silicon and get doping...

    1. This post has been deleted by its author

      1. James Cane

        Re: Hand Made Vacuum Tubes by Claude Paillard

        Thank you. That was 12 minutes well spent.

        1. Martin-73 Silver badge

          Re: Hand Made Vacuum Tubes by Claude Paillard

          Seen this video dozens of times. It's worth the 17 minutes every time. More wine!

      2. Nigel 11

        If you really want to go off-piste ...

        A technology that existed in Babbage's time, but of which Babbage was unaware, is hydraulic logic. It's possible to create a bistable out of fluid (air) being pumped through an appropriately shaped cavity, and to switch it between its two stable states using pipework connected to the output of others. Logic gates are also feasible.

        Anyone fancy building the world's first (?) hydraulic programmable computer?

        Or even a simulation thereof, just to hear what it might sound like while it is computing.

        1. Frumious Bandersnatch Silver badge

          Re: If you really want to go off-piste ...

          re: hydraulic computers, there was MONIAC but I'm not sure if it counts as hydraulic (involving water pressure in some useful way) or a computer in the usual sense.

          What prompted me to reply, though, was that I just recently came across the idea of a hydraulic ram pump. Sounds like it would make an excellent component in this speculative machine.

          Now you've got me thinking about powering stuff with water in Minecraft :(

    2. Anonymous Coward
      Anonymous Coward

      Re: Get some Silicon and get doping

      Great suggestion. With a bit of care, he may even be able to put more than one transistor on the same piece of silicon, and save on all that tedious wiring interconnect. Perhaps he could use some sort of photographic system so that the repeating units don't have to be drawn by hand.

  5. Esme

    Gosh. Well done thet man! Although if I'd had the knowhow and wherewithal, I'd have gone for replicating a 6502, always prefered the instruction set for them over the 8080. Less transistors to connect up, too, apparently (I'm astonished the 6502 used so few - I honestly thought it was more like an order of magnitude more than that!).

    1. ZanzibarRastapopulous

      Looking at that table the 6502 was something of a wonder of efficiency, makes ARM look hefty..

  6. GrumpyOldMan

    The finished circuitry, when mounted on a wall of boards, will measure 14 metres long and 2 metres high (46ft by 6.6ft), will weigh about a half-ton, and will consume 500W.

    So a bit like my old XT then?

    1. wolfetone Silver badge

      As the current owner of a PC XT, I can confirm that this is indeed the case.

  7. Alister Silver badge
    Facepalm

    Each transistor acts like a digital switch, and can be chained together to form huge decision-making circuits that execute software, instruction by instruction.

    Wow, amazing. So that's how they do it is it?

    I always thought it was done by little Elves, or something.

    1. Alister Silver badge
      Unhappy

      Okay.

      To all the downvoters of my comment above, do you really need to be told that a transistor is a digital switch? on an El Reg Forum?

      That was the point of my post.

      I'm in awe of the Prof, and think it's a great (if bonkers) project.

      1. James Cane

        Digital switch?

        Um, aren't most switches digital? Do you mean electronic?

      2. Mark 85 Silver badge

        To all the downvoters of my comment above, do you really need to be told that a transistor is a digital switch? on an El Reg Forum?

        That's entirely possible. There's lots of people in tech who don't understand the basic tech. For most, the operational theory behind the processor is the FM* Theory of Operation.

        * aka: Freakin' Magic

        1. Charles Manning

          "That's entirely possible. There's lots of people in tech who don't understand the basic tech."

          Any of them will be used to abuse by now.

        2. Nigel 11

          I've met computer science graduates who don't understand the connection between writing a value to an output port:

          *port=0x3c

          and (say) light number 3 going to brightness level 12/16.

      3. Terry 6 Silver badge

        What! I thought it was done by elves.

        Does that mean I didn't need to pour the biscuits and milk into the laptop after all?

      4. the spectacularly refined chap

        To all the downvoters of my comment above, do you really need to be told that a transistor is a digital switch?

        No, I don't need to be told that. You think that a transistor is a digital switch. I know that it isn't. You can wire them into an arrangement where their gain is high enough that it makes no difference and the resulting system behaviour is very digital, but that is in circuit. In isolation there are no ifs or buts, a transistor is an analog device.

        I did look into doing something similar to this a few years ago and it got much further than a thumbnail sketch. The goals were slightly different - this was a 38.4kHz 12-bitter with a few niceties (e.g. hardware multiply and divide) and a few oddities (hardware assisted garbage collection). It was a lot simpler than this, estimated at 3,500 transistors and perhaps 3ftx2ftx18" in size, but no integrated circuits anywhere - not even memory. Most of that reduction in complexity was down to the use of threshold logic gates which are a slightly quirky semi-analog system - digital inputs, digital outputs, but internally the processing is very analog in nature which allows for a much richer set of functions than pure Boolean logic. This approach was common for research systems in the 60s to reduce the complexity of the systems by exploiting that very analog nature of transistors.

        Utmost respect for the guy though because I know precisely what is involved. My project didn't get further than design, a few test assemblies, and a software emulator and assembler before the transistor I had based it around (BF199) went out of production. They were less than 3p each in quantity and when I saw the cheapest through hole alternative was £1.50 the entire thing went on the back burner.

        1. Joey M0usepad Silver badge

          "To all the downvoters of my comment above, do you really need to be told that a transistor is a digital switch?"

          As the refined chap said , that is far from the case - thats why there are big ones with big heat sinks attached in your amplifier.

      5. werdsmith Silver badge

        "To all the downvoters of my comment above, do you really need to be told that a transistor is a digital switch? on an El Reg Forum?

        I didn't downvote you (I don't use the up/down vote thingies, because I am over 12 years old) but my memory of college fiddling with transistors and doing calculations about how to bias the base so that it operated in the "knee" part of the accompanying datasheet graph made them work in a very analogue way as they were transitioning. Hence the analogue output of a transistor amplifier. They can work as a switch, but there is more to a transistor than the behaviour of a relay.

        Of course, this makes no difference the way that transistors are being used for this project.

        After I left college and fell into the world of hardware development, I found that using transistors in projects was done using shortcuts and I didn't have to think about all that NPN PNP shit ever again.

        Off the top of my head, did silicon bias at 0.7V, germanium at 0.5V? It''s been 25 years since I did hardware, little has been retained.

      6. Solmyr ibn Wali Barad

        "do you really need to be told that a transistor is a digital switch?"

        Article said "acts like a digital switch". Which is correct in the current context. Saying that it *is* a switch sounds like an universal claim.

  8. Anonymous Coward
    Anonymous Coward

    Individual transistors and LEDs - sure - but hand made wiring looms? I'd at least have gone for some PCBs for the backplane (with hand made looms linking the PCBs together). Density of components looks low enough that even one sided PCBs would work with small hand soldered bridges to jump wires.

    Fair play indeed - more patience than I have ...

    1. Simon Harris Silver badge

      If you look at his website, where the pictures are bigger, you'll see there are PCBs for the modules, mostly linked together via ribbon cable terminated with IDC connectors.

  9. Neil Barnes Silver badge
    Boffin

    Kudos and beer

    That's most impressive. I designed and built a sort-of hybrid 8080/6502 from discrete TTL, so just eight bits, and even that took four Eurocards (and several months of simulation beforehand).

    Now if only one of the chip makers had got around to doing a 74HC ALU chip...

    1. bonkers

      Re: Kudos and beer

      They did, the 74181.

      1. Neil Barnes Silver badge

        Re: Kudos and beer

        Yah. But it only appears to be still available in the hot'n'hungry 'LS181 version. :(

        1. Simon Harris Silver badge

          Re: Kudos and beer

          If you're still interested LittleDiode claim to have some of the HC variety in stock.

        2. Solmyr ibn Wali Barad

          Re: Kudos and beer

          Quite obtainable.

          https://octopart.com/search?q=74HC181

          1. Neil Barnes Silver badge

            Re: Kudos and beer

            End of life or what? Looks like LittleDiode's rip-off prices for the UK... thanks, guys. Time to replace the huge proms that emulate an ALU.

            1. Solmyr ibn Wali Barad

              Re: Kudos and beer

              Yes, TI 74LS181 seems to be the only 181 still in production. If you wanted industrial quantities of HC181, then it's a bit tough, there are only leftovers.

    2. Dwarf Silver badge
      Thumb Up

      Re: Kudos and beer

      Seems someone else had similar ideas. An internet connected machine made from 74 series.

      http://www.homebrewcpu.com

  10. TonyJ Silver badge

    Tip of the hat

    I am always amazed at the dedication some people put into their hobby projects.

    And I agree with the other posting - THIS is the kind of thing that should be taught about in school.

    I don't envy him when it comes to troubleshooting it though. Ouch.

    1. keithpeter
      Windows

      Re: Tip of the hat

      "And I agree with the other posting - THIS is the kind of thing that should be taught about in school."

      OK TonyJ and anyone, what is the THIS that you want teaching?

      I'm serious.

      1. sabroni Silver badge

        Re: what is the THIS that you want teaching?

        How computers work, as opposed to how to use them.

        1. keithpeter
          Windows

          Re: what is the THIS that you want teaching?

          "How computers work, as opposed to how to use them."

          OK, so are we taking an historical/hardware approach or building up from logic (and/or/not and Boolean algebra, leading to shift registers, half adders &c) or from the conceptual side (Von Neumann machine/Turing computability which rests on the 'diagonal proof' and its generalisation) or through programming (variables, assignment, loops, subroutines/functions then into more abstract areas) or all of those?

          Could take a bit of time (and need some serious skills). Best of luck. One tiny activity I use sometimes: take an 8 by 8 grid of squares on squared paper. Draw a resonably complex shape (each square is either black or white).

          Now devise a way of sending the shape to someone else using an sms message. Document the method for reconstructing the shape.

          Now find a method that will work for a shape drawn on a 16 by 16 grid, and then a 32 by 32 grid &c.

        2. werdsmith Silver badge

          Re: what is the THIS that you want teaching?

          It would be an exception for computers if we were to start teaching how they work.

          I don't believe that as part of the standard syllabus we are teaching how anything works to GCSE level apart from maybe light bulb filaments.

      2. TonyJ Silver badge

        Re: Tip of the hat

        "OK TonyJ and anyone, what is the THIS that you want teaching?"

        The underlying architecture of what drives a computer.

        How the core components from a transistor upwards come together to make a gate. How gates come together to build logic. How... and so on.

        In other words, it's all well and good showing kids how to use PowerPoint, but let's start by showing them how the actual computer works.

        1. Steve Davies 3 Silver badge
          Coat

          Re: Tip of the hat

          In other words, it's all well and good showing kids how to use PowerPoint, but let's start by showing them how the actual computer works.

          Using animated powerpoint naturally

          Mines the one with a wire-wrap tool in the pocket (yes I have one from the days of actually wiring up computer backplanes)

  11. Jim Lewis

    If possible I would also have opted to replicate suitable chip based registers with an option to swap them in/out as necessary during fault finding.

  12. Terry 6 Silver badge

    Next project

    Imagine the handwired Smartphone.

  13. Crisp Silver badge

    It's so beautiful!

    And something that I've always wanted to do myself.

    A work of art of that quality deserves to be in a museum for all to see.

  14. string
    Trollface

    but can it run crysis?

    1. Rich 11 Silver badge

      In ASCII mode, yes.

      1. Simon Harris Silver badge

        ... on an ASR33 at 110 baud.

    2. James Cane

      Actually yes, if you give it access to a large enough persistent data store and spent the time writing a PC emulator for it.

      The speed wouldn't be much to write home about - we'd be talking about one frame every few thousand years I reckon - and there'd be no visual display on a monitor. But yes, in principle, it could.

      1. FartingHippo
        Mushroom

        A strange game

        The only winning move is not to play. How about a nice game of chess?

        1. ElectricFox
          Boffin

          Re: A strange game

          It will run a text version of Crysis:

          You are flying through the alien caverns

          Your nanosuit is configured to maximum speed

          You see a button.

          What wouldst thou do?

          =>

  15. carup008

    Really?

    Some people have far too much spare time and money on their hands!

    1. Destroy All Monsters Silver badge

      Re: Really?

      One of the nastier side-effects of having enough capital infrastructure to escape subsistence farming.

      In the old times, one would take to the Mayflower in protest and sail west.

    2. hplasm Silver badge
      Meh

      Re: Really?

      "Some people have far too much spare time and money on their hands!"

      Yes, and spend them on Sky TV and paying for footy millionaire's cars.

      1. DropBear Silver badge
        Unhappy

        Re: Really?

        It always amazes me that some people allegedly don't have to spend 25 hours out of 24 simply to ensure their continued existence. It must surely be a wonderful feeling.

    3. MJI Silver badge

      Re: Really?

      Have you ever thought about thaving a hobby or two?

  16. Joey

    Some day, all computers will be made like this. This miniaturisation thing has had its day. Long live the 2N2222!

  17. Christoph Silver badge

    3,500 LEDs

    It's a real computer - it has Blinkenlights!

    But he really ought to be winding his own Core memory.

    1. Simon Harris Silver badge

      Re: 3,500 LEDs

      The memory appears to be an array of bistable flip-flops with a density of approximately 1 bit per square inch.

      1. Matt Langley

        Re: 3,500 LEDs

        In Minecraft, people dream of such density!

  18. Tom 64
    Pint

    Can he do me a Radeon Fury?

    They only weigh in at 8.9 billion transistors, he'll be done by lunchtime, right?

    1. Anonymous Coward
      Anonymous Coward

      Re: Can he do me a Radeon Fury?

      "They only weigh in at 8.9 billion transistors, he'll be done by lunchtime, right?"

      You sound like my manager.

      AC for obvious reasons.

  19. JimmyPage Silver badge
    Thumb Up

    Reminds me at Uni ...

    I programmed a bit-slice CPU ...

    And hand soldered my final year project.

    1. wabbit347

      Re: Reminds me at Uni ...

      A very cool project.

      Reminds me a bit of "The Elements of Computing Systems" , although the book used software emulators so you don't need so much physical space. Enough to get started on the principles of CPU design though.

      (not associated in any way with this, just an interested reader that bought the book)

    2. TonyJ Silver badge

      Re: Reminds me at Uni ...

      "Reminds me at Uni ...

      I programmed a bit-slice CPU ...

      And hand soldered my final year project."

      Mine were much less fun.

      Had to design and build a bar code reader. It did the utterly pointless thing of reading the bar code, and recreating it on a plotter - also built by me.

      Had to build a memory expansion for the "D5E evaluation kit" to hold the necessary lookup tables and "driver" for the plotter.

      I learned far more about bar codes than anyone would ever really wish to know. :)

    3. Anonymous Coward
      Anonymous Coward

      Re: Reminds me at Uni ...

      Same here. Nat Semi IMP16P circa 1974/75

      around the time when the real JPage was at his best.

      http://www.bbc.co.uk/news/entertainment-arts-29550639

      Used a 2901 4bit slice (for a 16bit CPU) for a Real Time interface some years later.

  20. a well wisher

    Just call him Von !

  21. Winkypop Silver badge
    Coat

    That's quite a bit of work

    I hope he solders on....

    1. Spiracle
      Coat

      Re: That's quite a bit of work

      He should do. He sounds fairly down to earth...

      1. Crisp Silver badge

        Re: That's quite a bit of work

        He seems to know watt he's doing.

  22. chris swain

    Mucho kudos to Mr (von)Newman

    Totally agree with the commenters who suggest housing this in a public institution as an educational exhibit. NMoC was my first thought but Cambridge makes more sense geographically (damn you both - put it in my local science museum so that I can go and ogle it!).

    El Reg is being a tad lazy by comparing its performance to integrated circuits of yore. It would be nice to see how it stacks up on the whole continuum of computing, at least as far back as the first valve-based systems.

    All hail the man in a shed (or spare bedroom) with too much time on his hands!

    (And before anyone points it out I know it's von Neumann)

  23. cantankerous swineherd

    a grateful nation should give that man a shed!

    1. Anonymous Custard Silver badge

      And a pipe...

  24. This post has been deleted by its author

    1. Simon Harris Silver badge

      Re: For fuck's sake.

      Maybe his oscillator is off by 2.4%

    2. DropBear Silver badge
      Trollface

      Re: For fuck's sake.

      "It's kHz, not KHz."

      Yeah, yeah, sure, but which one is 1.000 kilocycles and which one is 1.024...?

  25. Anonymous Coward
    Joke

    This is brilliant...

    ...but when is he going to start on the GPU?

    1. John Tserkezis

      Re: This is brilliant...

      "...but when is he going to start on the GPU?"

      Soon. If you can't log into facebook with it, the kids lose interest.

  26. Tom Wood

    I must be the only software guy here

    because I think it's a ridiculous project :-)

    Just because you can, doesn't mean you should. This is the opposite of progress - deliberately doing thousands of small repetitive tasks that a machine can do much better (for almost every definition of better - smaller, faster, cheaper, more reliably, using less resources)...

    1. James Cane

      Re: I must be the only software guy here

      I'm a software guy too and this is high art.

      Software doesn't really exist. Everything is hardware. Software guys should remember that more often.

      1. James Hughes 1

        Re: I must be the only software guy here

        I'm also a software guy. I think this is an awesome project!

    2. Mark 85 Silver badge

      Re: I must be the only software guy here

      Did you forget the troll icon, maybe?

    3. sysconfig

      Re: I must be the only software guy here

      "This is the opposite of progress [...] a machine can do much better "

      Yes, it is, and a step back in time. It goes back to the roots and *wonderfully* demonstrates how computers work. I can see that being a fantastic educational tool for those who want to learn about it, before they go off and build machines which produce the next generation of Raspberry Pi.

      You didn't think that this 14x2m project was going to go into mass production for you to buy and use, did you?

    4. chris swain

      Re: I must be the only software guy here

      And I suppose you exist on a diet of soylent rather than waste your time on inefficient cooked food?

    5. 404 Silver badge

      Reading suggestion

      The Foundation series by Issac Asimov.

      Specifically the decline of the Empire and the Engineer Priest class.

  27. Anonymous Coward
    Anonymous Coward

    Would be better using discrete logic surely?

    Wiring up big boards of TTL isn't uncommon, that's what the original Amiga chipset was done with.

    http://www.amigahistory.plus.com/prototypes/cbm-lorraine-daphne-agnus.jpg

    1. Dr_N Silver badge

      How about 7400 ICs and wire-wrap ?

      1. TonyJ Silver badge

        "How about 7400 ICs and wire-wrap ?"

        Oh god I loathed wire wrapping.

        But...the end results looked enchanting. Almost beautiful if done properly.

        It's worth noting, not much (if any) of mine did! :)

      2. kventin

        something like this?

        http://www.homebrewcpu.com/

    2. Simon Harris Silver badge

      "Would be better using discrete logic surely?"

      Nothing wrong with doing it with discrete logic, or valves for that matter, if that's your own preference - the challenge of building it with discrete transistors is his.

  28. harmjschoonhoven
    Go

    Transistors?

    No, no, no. A real vintage computer uses (hand-wired) relays like the ARRA I

    1. Kubla Cant Silver badge

      Re: Transistors?

      No. Gears.

  29. Anonymous Coward
    Anonymous Coward

    500W at what voltage?

    I shudder to think he'd be running it at 5V… that's a 100A busbar that'd be needed to power the thing!

    I've seen what power leads carrying 400A look like, feeding a 20kW 3-phase BLDC motor. We'd lock the rotor to measure torque, in doing so, we'd watch two wires get attracted to each other, and two repel each other according to magnetism (F = (µ₀I₁I₂l)/(2πr)).

  30. Simon Harris Silver badge

    Drum storage...

    Will he be 'repurposing' the washing machine?

  31. This post has been deleted by its author

  32. This post has been deleted by its author

    1. Simon Harris Silver badge

      I'm waiting for the FORTRAN compiler.

  33. MacroRodent Silver badge

    Quite a challenge

    ...building a 16-bit system. Doing a 8-bit design would have been less than half the work. If he had chosen to clone the 6502 or some other early 8-bit CPU, there would also have been lots of existing software to run. But maybe he considered it too easy.

    1. the spectacularly refined chap

      Re: Quite a challenge

      Doing a 8-bit design would have been less than half the work.

      That is something of a mixed bag. It reduces complexity in terms of components and wiring but significantly increases design effort. Large parts of a 16 bitter are simply the equivalent 8 bit circuit replicated but going in the other direction introduces some significant extra issues. Presumably you would want to address more than 256 bytes memory so that makes an address (at least) two words long. Similarly it's somewhere between difficult and impossible to encode a complete, useful instruction set in eight bits so you have multi-word instructions too. That gives you a large amount of hassle co-ordinating those half quantities and you need multiple cycles to send those values around. That in turn adds complications as you co-ordinate timing in multiple-cycle instructions.

      I mentioned somewhere above that 12-bitter I set about designing a few years ago. 12 bits was chosen very deliberately as the simplest option - it's the narrowest width where you can sensibly have arithmetic, addresses and instructions all the same length. All instructions were single cycle so keeping everything in sync was also made a lot simpler, even if multiple cycles would have allowed you to crank up the clock rate a little. It did limit you to a 4096 word address space but I considered that adequate for a demonstration system.

      1. MacroRodent Silver badge

        Re: Quite a challenge

        The 6502 does everything in 8-bits width, except addresses. An opcode byte is optionally followed by an 1 byte immediate value, or a 1 or 2 byte address. I'm guessing that it has 2-bit field in the instruction byte that causes it to load 0, 1 or 2 following bytes to a register determined by rest of the opcode (and increment the PC). If performance is no big concern, shouldn't this operand loading sequence be implementable with a simple state machine? Though I must admit my knowledge about CPU design comes from one mostly-forgotten university course a quarter-century ago... (the final exercise was creating a paper design, which was not even simulated, never mind built.)

        1. Simon Harris Silver badge

          Re: Quite a challenge

          Here is an interesting piece on how the 6502 decodes instructions:

          http://www.pagetable.com/?p=39

          It explains how the instruction decode causes undefined opcodes to do the strange things that they do.

  34. Anonymous Coward
    Anonymous Coward

    We tried making a RAM register with air pistons.

    We managed to make one single register, but we used all of post-grad air pistons kit in our pneumatics lab. Just for the heck of it. Ours could retain the ram memory even without power, obviously. It would have become even bigger if we tried to do anything larger.

    But hey, kudos, that was mighty impressive. I guess that's what would have happened if we didn't have single-die processors, or in a post-apocalyptic steampunk future.

  35. Bob H

    Is there any reason for the slow clock speed?

    Any reason not to use SMD instead of through hole?

    1. Simon Harris Silver badge

      You might want to read the creator's web pages, particularly this one...

      http://megaprocessor.com/progress.html

      where he explains the limitation.

  36. Jagged

    Can we change the photographers name from Newman to Neumann?

  37. gerdesj
    Linux

    WINE

    To do list:

    * Run up the assembler and simulator in WINE.

    * Learn just enough assembler to try and understand what on earth is going on.

    Sounds like a project for tonight.

  38. Tom 7 Silver badge

    Mips???

    You'll find most instructions take at least 3 cycles or more so 0.02 Mips is a bit of a sales figure.

  39. Matt Langley

    That's cheating - he should do it in Minecraft.

    That's nothing, when he can do it in Minecraft, I'll be impressed.

    (And before I get spammed, yes I know there are Minecraft computers, but the limitations of the 'platform' do quickly make large scale computer exponentially more difficult than actual computer construction, so they tend to be rubbish.)

    1. Simon Harris Silver badge

      Re: That's cheating - he should do it in Minecraft.

      Minecraft? It would be cheating to do it as a simulation.

      Why not get back to reality and do it with Lego?

      1. Matt Langley

        Re: That's cheating - he should do it in Minecraft.

        No Not gates in lego, but I like your thinking.

  40. John Savard Silver badge

    I'm shocked. The thing is costing more than a PDP-8 did. And these days, one ought to be able to find discrete transistors cheaply in old junk people are throwing away.

    Actually, that would have been more true a decade or so ago. These days, the "junk" has become valuable antiques.

    1. teacake

      "And these days, one ought to be able to find discrete transistors cheaply in old junk people are throwing away."

      He's already mentioned that reliability is likely to be an issue, and that's without using old components of uncertain provenance and condition.

  41. Steve Todd

    PDP 8 anyone

    The original version of that was all discrete transistors and diodes, no ICs in sight. Plus it had lots of blinkenlights.

  42. TWB

    I wish I could help out

    I don't live nearby and don't have the time but would love to help out if I could. I have joked for several years about buying replacement gates/pixels/ccd cells etc for stuff at work [TV engineering] (no one laughs for some reason...........I know, I know)

    I wonder if you can step-by-step the clock for debugging?

    1. Simon Harris Silver badge

      Re: I wish I could help out

      "I wonder if you can step-by-step the clock for debugging?"

      Apparently, yes.

      http://megaprocessor.com/VitalStatistics.html

  43. Anonymous Coward
    Anonymous Coward

    We might have a very nice home for your pet and you can visit! :-)

    How about the Centre for Computing History in Cambridge?

    www.ComputingHistory.org.uk

  44. Christian Berger Silver badge

    Cool project, but if you want to have it easy...

    As a German engineer, and therefore a rather lazy person, I have to point out that there's a way to make such a computer with _much_ less parts at the expense of speed.

    The idea is that you build a bit serial computer. This means that lots of parts will suddenly become a lot simpler. You can still have 16 bit words, but your ALU, for example will just process one bit a time. Your registers become shift registers with a one bit input and a one bit output. All your buses will also have one bit and clock in their values serially.

    There's a book describing such a system. I think it's called "Elektronische Rechenmaschinen". I think it describes a 20 bit machine working bit serially. Back in the early days of building computers, reducing the complexity was essential for many teams building a computer. Trading a factor of n in speed for a factor n of complexity seemed a _really_ good idea back then. Particularly since back then as now, computers rarely were fully utilized.

    1. metasonix

      Re: Cool project, but if you want to have it easy...

      >The idea is that you build a bit serial computer.

      That is exactly how most tube/valve computers were designed. It saved enormous amounts of circuitry, although a magnetic drum memory was mandatory to hold all the data and registers. And damn were they slow.

      https://en.wikipedia.org/wiki/LGP-30

      1. Nigel 11

        Re: Cool project, but if you want to have it easy...

        There's also bit-serial parallel computing ... SIMD, with one instruction at a time broadcast to an array of one-bit processors. The ICL DAP, if there's anyone else out there who can remember that ill-fated project. I had great fun one summer learning to program it in assembly language.

  45. JustNiz

    Even though I am a geek I oficially don't get why anyone would spend so much time/money/space doing this as you can just go out and buy a functionally much better CPU for pennies that would fit easily into a matchbox.

    Heck if he just wanted to see his processor design implemented he could/should have just programmed it into a PLD or something.

    1. werdsmith Silver badge

      "Even though I am a geek I oficially don't get why anyone would spend so much time/money/space doing this as you can just go out and buy a functionally much better CPU for pennies that would fit easily into a matchbox."

      It's quite tricky to teach visually about CPU logic design using a CPU in a matchbox. It would be like training a chef to prepare food by giving him a fiver and telling him to go and buy a big mac.

      And you matchbox wouldn't get you publicity, a shining CV, unlimited admiration.

      Or have I been whooshed?

  46. Kevin McMurtrie Silver badge

    TO-92!!!!

    I can think of no nightmare worse than hand-wiring 14000 of the TO-92 transistors pictured. They wiggle around unless you bend the leads, and bending the leads causes solder bridges. After all that, you'll find that one is in backwards and the slightly bent leads have anchored it down with such incredible strength that molten solder spatters everywhere when you pull it out.

    1. metasonix

      Re: TO-92!!!!

      Obviously he's not Mr. Ten-Thumbs or he wouldn't even try it. At least he's using PC boards. That will help with assembly and overall reliability.

  47. PT
    WTF?

    Meh. My then-girlfriend's dad did something like this in 1967, though sensibly restricted it to 4 bits so that it only took up part of a room.

  48. Colin Tree

    stack based

    could have saved himself a lot of effort by using stack based architecture like the 6502

    1. MacroRodent Silver badge

      Re: stack based

      The 6502 is not a stack-based machine. It does support a stack for push, pop and subroutine call instructions, but so does almost every other microprocessor. I think the 6502 can be best described as an accumulator machine, where all arithmetic and logical instructions require one of the operands to be in the accumulator (A) register. (The first CPU I ever tried programming in machine language, on the Oric 1, which is why I go on about it...).

      1. OhDearHimAgain

        Re: stack based

        I still have my 16kb Oric-1 and it still works fine - remember "zap", "ping", "shoot" & "explode" ?

        1. MacroRodent Silver badge

          Re: stack based

          Sure! Zap, ping etc. made the Oric easier to get started with, as I remember in C64 you needed peeks and pokes for sound effects. Sadly my Oric 1 (64k) does not boot any more, I suspect the EPROM has lost its contents.

  49. Fred Flintstone Gold badge

    I so love that *classic* understatement

    "Things got out of hand at that point."

    You don't say :). Admirable effort.

  50. Andrew Torrance

    Instruction set type ?

    If anyone is tempted to do something similar , a nice compromise might be to start off looking at the AMD 2900 family of chips . https://en.wikipedia.org/wiki/AMD_Am2900 . This stuff starts at the ALU level . But being interested in this stuff , does anyone know if he went for a RISC setup with microcode ?

  51. macaroo

    My Early Days

    This takes me back to my early days as a young lad. Exploring the basic precepts of computer logic down to the register level and instruction flow thru the various transistor gates. Wonder and excitement in exploring a new world of technology.

  52. Unicornpiss Silver badge
    Pint

    Several things...

    --That is an amazing undertaking, and a smart guy to build a processor from scratch.

    --He obviously has a lot more free time and ambition than I have.

    --Troubleshooting shouldn't be that bad as long as he has a diagram. He obviously understands the principles of operation, so he would just need to put a scope on the correct test point and make sure signals are present. The behavior will tip you off as to what's wrong. Many years ago when I took electronics, we had a donated DEC PDP 11/70. Our instructor would sabotage it, and armed with blueprints and a scope, we'd have to find the faulty component or failed wiring.

    --Looking at the MIPs on the processor comparison, it's obvious the MOS6502 was the greatest bang for the buck in its day. Half the transistors and clock speed and still as fast as its competitors.

    That is all :)

  53. Harry the Bastard
    Pint

    more of this heroic nonsense!

    designed a cpu with 10k ecl once, i thought that drew a lot of power, but 500w has me beat

    hurrah to him!

  54. Ed Jackson

    But will it run Fallout 4?

  55. OhDearHimAgain

    Totally brilliant, but not exactly "transistor by transistor"

    There's a lot of chips on there - presumably LSI discrete logic, but all the same - not "transistor by transistor"

    1. Simon Harris Silver badge

      Re: Totally brilliant, but not exactly "transistor by transistor"

      All the logic that does computation is done transistor by transistor.

      The only place that LSI has been used is on the 7-segment display boards - apparently it was too complex decoding hex (octal?) digits to a 7-segment display in transistors for something that is there 'for debugging purposes'. To quote Newman...

      "I spent a bit of time trying to work out how to do the 7-segment display using discrete transistors but the answer is vast. Really, really big. It would have near doubled the size of the thing and the circuitry for the display would have obscured the circuitry for the processor which would have undermined what I was trying to do. As its only for debug and not proper function I went for chips. This is definitely NOT cheating, it is just for debug. It is irritating though."

  56. Soap Distant

    Utterly stunning! The website is amazing. Our so called tech friendly gov should be funding this!

    SD

  57. Unicornpiss Silver badge
    Thumb Up

    6502 fan...

    Looking at his website, this article doesn't do justice to the scope of the project. Am I correct in my deduction that he is using "zero page" memory as another set of registers for results, very "6502-like"?

  58. Rtbcomp

    Brilliant

    The IT equivalent of the Tornado steam engine.

    Mainframes were like this when I was a lad!

  59. raving angry loony

    Amazing

    To me it's an amazing achievement of education over rationality. Far as I'm concerned, if "James" doesn't at LEAST get awarded a Masters (even honorary) over this, I'll be annoyed with the universities. Not sure if it's worthy of a doctorate, although perhaps he deserves one in education. That said, many people have received doctorates for a lot less. Even in computer science.

    Assuming the poor fucker doesn't already have one, which is why he's doing this in the first place.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2019