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The 8-Bit Computer That's Been Built By Hand

Posted by Soulskill on from the just-enough-bits-for-mario dept.

nk497 writes "Forget snapping a few components into a motherboard — programming enthusiast Jack Eisenmann has made his own PC from scratch. His Duo Adept, as he's named it, features 64KB of main memory, 256 bytes of RAM and, in total, 263 lines of code for his homemade OS. Sure, it can't run Crysis, but it does run a game he's written himself."

117 of 161 comments (clear)

  1. Old school by Zakabog · · Score: 4, Interesting

    I wasn't around for this sort of stuff but wasn't this the sort of thing Radio Shacks customers were doing 25+ years ago?

    1. Re:Old school by NixieBunny · · Score: 1

      Yes, we were. My brother and I started with a Motorola MEK6800D1 board and took it from there. It's amazing what you can fit in 4K of RAM if you have to.

      --
      The determined Real Programmer can write Fortran programs in any language.
    2. Re:Old school by brainboyz · · Score: 1

      Pretty much. I would've been impressed if he had done it from actual transistors not full-blown ICs, but given CompEng students make stuff like this in school (admittedly, with FPGAs, but the concept is the same) it's not as complex as it looks. I'd say the hardest part is probably the output to monitor. The wiring would be tedious, but not unthinkable.

    3. Re:Old school by frank_adrian314159 · · Score: 1

      Yes. I built a simple CPU+memory system in school around 1979 or so. That's 32 years ago.

      --
      That is all.
    4. Re:Old school by Anonymous Coward · · Score: 1

      This guy built a home-built *CPU* from TTL chips. So, no, it's considerably more impressive that using any kind of dev board with an onboard microprocessor.

      (You're starting with RAM already existing - he isn't.)

    5. Re:Old school by dotwhynot · · Score: 1

      I wasn't around for this sort of stuff but wasn't this the sort of thing Radio Shacks customers were doing 25+ years ago?

      Indeed. I built a 6502 machine with the help of an electronics magazine, starting with actually etching my own circuit boards. It had an hexadecimal display and keyboard (thanks to manual Dymo of old), only the imagination was the limitation. And yes, I did write a game for it.

    6. Re:Old school by j00r0m4nc3r · · Score: 3, Funny

      TTL chips? Luxury! When I was a lad we had to use coconuts and vine to fashion NAND gates.

    7. Re:Old school by engineerofsorts · · Score: 1

      Circa 1975-76, this was just a design exercise at the tail-end of our logic design class--we just called it a minicomputer then, using SSI and MSI TTL modules--it would have been a bit tricky to come up with 64K of storage then, since 1Kbit to maybe 4Kbit chips was state of the art. If anything, you do have to commend the guy, not for design, but for getting such a large number of proto-boards and all those aggravating wires hooked up and get all of it working. A wire-wrapped version would be more compact/reliable, and just about as "homemade" in my book. No big deal.

      --
      Life is tough. Life is even tougher when you're stupid.
    8. Re:Old school by MightyMartian · · Score: 1

      Yup, this isn't just going and getting some old 6502 or Z80 and building a new computer around it. That's been done plenty over the last thirty-odd years. This guy has actually built an 8-bit CPU. Fuck, I'd be impressed if he'd built a 4-bit processor, but this is pretty damned cool.

      --
      The world's burning. Moped Jesus spotted on I50. Details at 11.
    9. Re:Old school by Dachannien · · Score: 2

      There are two differences. One, he didn't use a prefab microprocessor - he built one from gates, counters, etc. And two, his website hasn't collapsed from the slashdotting.

    10. Re:Old school by msobkow · · Score: 3, Insightful

      The hard part is finding the loose wire.

      --
      I do not fail; I succeed at finding out what does not work.
    11. Re:Old school by camperdave · · Score: 1

      I had a book, back in the long ago, called "How to Build a Microcomputer and Really Understand It". It walked you through building a 6502 based machine. It had PCB printouts that you could photo-resist onto circuit boards. You would build dozens of "nybble cards": circuit boards with edge connectors and a binary pattern of diodes to encode 4 bits of information. By inserting these cards two at a time into edge connector sockets, you could do some simple programming. I loaned it out and never got it back.

      --
      When our name is on the back of your car, we're behind you all the way!
    12. Re:Old school by JeremyR · · Score: 1

      That's pretty much what we did in a CS/EE class. Designed a CPU from scratch, put the microcode on a FPLA and used a bunch of supporting TTL chips. If I recall correctly, it was 16-bit, but it might have been 8. He has taken it a step further with video output, and that's impressive (at least to me).

    13. Re:Old school by Anonymous Coward · · Score: 2, Interesting

      Err, I may have confused this with another story - from here. If I have, sorry.

      Neverthless, it seems this story is, however, not unique even in the modern day.

    14. Re:Old school by TrisexualPuppy · · Score: 2

      TTL chips? Luxury! When I was a lad we had to use coconuts and vine to fashion NAND gates.

      Gilligan, don't forget the NOT gate that we fashioned out of the two transistors from the radio or the infinite power source that came out of it. Now why couldn't have that satellite flown overhead a few moments after we completed the digital telecommunicator device?

      --The Professor

    15. Re:Old school by Deltaspectre · · Score: 1

      Same here, in computer design. Used some PLDs with ridiculous gate limits and at the end of the project, we were playing a counting game via serial

      --
      My UID is prime... is yours?
    16. Re:Old school by ckeck · · Score: 1

      Survived the Slashdotting because his site is hosted on MobileMe ;)

    17. Re:Old school by ShakaUVM · · Score: 1

      Building a functioning 8-bit CPU and writing apps for it was required for graduating from our CS program at UC San Diego... not seeing why this is newsworthy.

    18. Re:Old school by Dachannien · · Score: 1

      You make a good point. Maybe none of us should be impressed unless the formation of a new universe is somehow involved.

    19. Re:Old school by strags · · Score: 1

      To be fair, that's not exactly comparing apples and apples. You didn't actually MAKE the 6502 itself, which is much closer to what he's done here. That said, yes, plenty of others have done this.

    20. Re:Old school by jhoegl · · Score: 1

      I think its the fact that there are still "web rings"... WTF?!?!?

    21. Re:Old school by HBSLTV · · Score: 1

      it's worth noting he's in high school, not college... http://youtu.be/qYvr0b8jqbg

    22. Re:Old school by Pseudonym · · Score: 1

      Not really, no. 25 years ago you could buy a Z80 or 8085 in that kind of store for cheap, so there was no need to build your own CPU from TTL.

      Yes, I was there.

      --
      sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
    23. Re:Old school by garyebickford · · Score: 1

      Oblig. XKCD strip.
      "So if you see a mote of dust vanish from your vision in a little flash or something, I'm sorry, I must have misplaced a rock."

      --
      It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
    24. Re:Old school by barneythebigdog · · Score: 2

      you are missing the point here...this was done by a kid who just finished high school...i think it is amazing!

    25. Re:Old school by jshackney · · Score: 1

      A thousand monkeys standing around a box of parts would "accidentally" build a computer long before I figure it out. I'm impressed by what this guy did.

    26. Re:Old school by Jeremi · · Score: 4, Funny

      A thousand monkeys standing around a box of parts would "accidentally" build a computer

      Ah, I see you are familiar with the TRS-80.

      --


      I don't care if it's 90,000 hectares. That lake was not my doing.
    27. Re:Old school by sartin · · Score: 1

      This guy has actually built an 8-bit CPU. Fuck, I'd be impressed if he'd built a 4-bit processor, but this is pretty damned cool.

      Been there done that. Standard undergrad project in a semester course introducing computer design in 1982. I took it in a compressed summer sessions over 5 weeks. We designed a four bit computer from scratch, built it, and wrote some programs for it. My group designed an eight bit CPU, too, but we didn't have time to breadboard; we wrote an 8 bit math library for the four bit CPU instead.

      I fail to see what is so impressive about this accomplishment.

    28. Re:Old school by Arlet · · Score: 1

      It's a lot easier with FPGAs, because the synthesis tools will make sure you meet all the timing constraints and setup/hold requirements, or will complain if it can't. They will also complain if you connect two outputs together, or do other silly things. With real hardware you have to do all of that yourself.

    29. Re:Old school by Nyder · · Score: 1

      A thousand monkeys standing around a box of parts would "accidentally" build a computer

      Ah, I see you are familiar with the TRS-80.

      Well, i have to hand it to those monkeys, my TRS-80 Mod 4p is still working...

      --
      Be seeing you...
    30. Re:Old school by drolli · · Score: 1

      Well. i thought he soldered it from discrete elements, like transistors. that would be something.

    31. Re:Old school by asdf7890 · · Score: 1

      It is rare these classes start from the point of having no CPU and RAM modules or anything, which is where this project started.

      For instance in my first year of CS out electronics module involved putting together an 8-bit machine, but we were given RAM and EEPROM chips plus a CPU (something Z80 based). The bit that wasn't just putting the data bus together was the actual programming of the CPU (that was done from scratch in assembler, and the result dumped onto the EEPROM) and the I/O sub-system (we created a vector based display using an oscilloscope, and used a simple keypad for user input). The most impressive demo at the end of term was one fella had a Cobra Mk III on screen rotating and moving in 3D, other demos included simple pong implementations. The extension project next term was to create a simple positioning system, which picked up signals output from a beacon in the room calculated their absolute position within the building.

      My point is that this lad has done all that (he has a raster based graphics output, but I assume the challenge was similar to our vector based one) *and* put together his own CPU and RAM rather than using pre-made TTL chips (though he used gate chips rather than making his own individual gates, that is quite different from using a pre-made RAM module and a world apart from the pre-made CPU we used). The whole machine, from scratch. And to top it off he is a little younger than a first year undergrad. So I think you are definitely underestimating his level of personal achievement here, and that he deserves that feeling of achievement. I just hope he has a couple of good friends to have a pizza and/or a beer or few with to celebrate his current 15 minutes of techie fame!

      FYI when I picked my Uni (some years ago now) I deliberately went for one whose CS course included a bit of this as well as the abstract math, programming and such. I'm of the opinion that a little dicking around with TTL chips is a useful part of a well rounded understanding of the industry.

    32. Re:Old school by L-four · · Score: 1

      Monkeys don't have enough entropy to do something like that.

    33. Re:Old school by ShakaUVM · · Score: 1

      >>it is newsworthy because this kid did this all on his own while he was in High School. With no training. What were you doing in High School?

      I did a summer internship between my junior and senior years with Dr. Clark Guest (an amazing EE Professor) at UCSD to work on a fuzzy logic AI system that ultimately got me a job at a defense contractor before I graduated. But nice try with your tu quoque attempt.

    34. Re:Old school by tibit · · Score: 1

      These days, you don't even need an FPGA. Take any fast multicore chip like Parallax Propeller or fast multithreaded chip like XMOS XC-1 and you can emulate pretty much any retro 4 or 8 bit CPU at native or faster speed. With video output. All pretty much single chip -- all you need is a clock crystal and some voltage regulators. The propeller has 8 completely independent cores called cogs, each with 4 kbytes of dedicated RAM, and 32 kbytes of shared RAM in so-called hub. XC-1 has hardware multithreading with zero-overhead thread switching: it can run 8 threads in parallel, and thread switch is done after each single instruction, and those usually each take 1 cycle so you have true 400/500 MIPS performance, with 32 bit transfers.

      There is a single cog Z80 implementation for Propeller, called ZiCOG, and it runs at about the speed of a Z80. Not cycle accurate, though. On XMOS, you can trivially run an order of magnitude faster, or more, and be cycle accurate at native speed. Both Propeller and XC-1 enable you to have a single-chip emulation of pretty much any 8 bit computer -- that is the CPU and everything else, with sound and video output. It's somewhat less work on XC-1 to keep it cycle accurate.

      --
      A successful API design takes a mixture of software design and pedagogy.
    35. Re:Old school by qubezz · · Score: 1

      The 1970's called, it said you are low tech. Here's an example of a single TTL board from a VAX. There must be about 300 individual TTL chips from the 7400 series on it (where one chip has 4 nand on it, etc). The left 29 boards in this VAXare the cpu.

      It is very noble to build your own CPU architecture with your own instruction set, however building CPUs out of gates in individual chips is just an exercise in wasting money when you can do the same thing on FPGAs, like the guy that built an entire Cray-1 on an FPGA development board. A more impressive project, the visual 6502 in javascript, made by scanning the actual chip and rebuilding the circuit out of individual transistors on the die, proves you don't even need hardware.

    36. Re:Old school by qubezz · · Score: 1

      Is that you, Chuck Peddle?

    37. Re:Old school by Tablizer · · Score: 1

      Yes, but you had Mary Ann in shorts, and we didn't.

      --
      Table-ized A.I.
    38. Re:Old school by GrpA · · Score: 1

      I don't think they are missing the point. I was building Z-80 based systems and computers when I was 15 and by the time I was 17, I was creating embedded systems with complete multitasking OS'es from scratch. I thought I was pretty clever until I made friends with a Romanian kid my age who built an his own CPU out of TTL logic because he couldn't get hold of a microprocessor CPU. We became good friends at the time.

      Over time, I met many others who had completed similar achievements. It's not as uncommon as you'd imagine. If I recall correctly, not a single one of our group ever made it through university, except the Romanian kid. I tried once and got kicked out of the electronics class for arguing with the lecturer ( what kind of an idiot makes a lab experiment that drives TTL outputs directly into other TTL outputs and leaves the inputs floating? Yes, he really was the inexperienced...) but got picked up by an R&D lab a month later.

      The main difference perhaps is that we were working on such projects because there was no other alternative. So nice things like keyboards? Forget it. We had to find whatever keyboards we could, desolder the original electronics,hand-wire a matrix to the keys and build the IO controls to read the keyboard. That was pretty normal. IO chips were sometimes difficult to get, but nothing shift registers couldn't fix with a little clever controlling logic. Make it on a separate board and it was suddenly a "module" that could be stacked. Buses were replaced by ribbon cables ( a luxury! ) and I still remember our excitement at presensitised PCBs and CAD software so we could hand-make circuit boards and no longer had to manually solder together protoboards for prototypes.

      Though in a world in which there's no need to do such things anymore, I still respect the kid's drive and motivation. Doing things the old way is hard. While I appreciate his desire to learn, I question whether he will achieve anything out of this other than satisfaction, though sometimes that is enough. :)

      GrpA

      --
      Enjoy science fiction? "Turing Evolved" - AI, Mecha, Androids and rail-gun battles. What more could you want?
  2. To bake an apple pie from scratch... by John.P.Jones · · Score: 3, Insightful

    Ever since Cosmos I can't take the phrase 'from scratch' seriously.

    Also there is this TED video where a guy tries to build a toaster from raw materials...

    1. Re:To bake an apple pie from scratch... by Anonymous Coward · · Score: 2, Informative

      http://www.ted.com/talks/thomas_thwaites_how_i_built_a_toaster_from_scratch.html

    2. Re:To bake an apple pie from scratch... by jawtheshark · · Score: 1

      Obviously, it's easy peasy to create your own universe... I mean, it's as easy as saying "let there be light".... Ooops, damned, I did it again. *sigh*

      --
      Ahhh...the great dumpster continuum. Many a free computer will be found there. -- sowth (748135)
    3. Re:To bake an apple pie from scratch... by tylernt · · Score: 3, Insightful

      Also there is this TED video where a guy tries to build a toaster from raw materials...

      I don't think people appreciate the "tech tree" (to use Starcraft parlance) you have to walk down to get to the simplest of modern household items. The toaster is a good example, but now imagine starting from zero -- you can't even start with iron ore, because you don't have any tools to mine it with! So start with banging rocks to get something sharp you can use to cut down a tree, so you can make a handle to make a stone axe. Hopefully this is enough to get some iron ore, but now you also need to make something to smelt your ore in, such as a bloomery. And for that, you need charcoal. And for that...

      Basically, the TED guy making his toaster cheated by used modern tools to get his raw materials. And even with cheating, his toaster never toasted any bread.

      The tech tree for a dollar store pocket calculator is staggering, let alone a Space Shuttle. I don't think many people are conscious of this when they toss that toaster in the garbage and spend $10 on a new one.

      --
      DRM 'manages access' in the same way that a prison 'manages freedom'
    4. Re:To bake an apple pie from scratch... by Neil+Boekend · · Score: 1

      He could have procured iron, smelted it and used it to make a toaster for toasting bread near a fire, like the one Bill Compton has in True Blood. See an 19th century toaster. Toaster.org has some other models without electricity. He decided he should make a modern toaster from scratch. Off course that's not going to work. Before electricity there were solutions to toast your bread.

      --
      Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
  3. wow by heptapod · · Score: 1

    holy shit, who knew that web rings still existed in the 21st century!

    1. Re:wow by nitehawk214 · · Score: 1

      holy shit, who knew that web rings still existed in the 21st century!

      Throwback to the 80's computer. Throwback to the 90's webpage.

      --
      I'm a good cook. I'm a fantastic eater. - Steven Brust
    2. Re:wow by camperdave · · Score: 1

      As a web ring, it sucks. I want to open the next site in the ring in a new tab, but it's Javascript controlled. It doesn't allow me to do it.

      --
      When our name is on the back of your car, we're behind you all the way!
  4. very cool by pz · · Score: 1

    Reminds me of the Maybe systems that MIT undergraduates build by hand in 6.004 (or used to, when I was involved) that were then programmed to emulate about 3 or 4 different architectures.

    --

    Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
    1. Re:very cool by Lord+of+Hyphens · · Score: 2

      Yeah, there's a upper-level undergraduate course that does single-board computers with a 8088 MPU and some supporting hardware. It's a mess and I personally believe that the course should be changed to give a "interfacing with reality" bent to it, as a single MCU can be tuned to do the same (external memory bus, etc) and you can go beyond the "look I made a light blink" to "Look I can actually do something useful with this thing".

      --
      "I've spent my whole life figuring out crazy ways to do things. It'll work." -- Montgomery Scott, "Relics"
    2. Re:very cool by Lord+of+Hyphens · · Score: 1

      Yeah, there's a upper-level undergraduate course that does single-board computers with a 8088 MPU and some supporting hardware. It's a mess and I personally believe that the course should be changed to give a "interfacing with reality" bent to it, as a single MCU can be tuned to do the same (external memory bus, etc) and you can go beyond the "look I made a light blink" to "Look I can actually do something useful with this thing".

      Upper-level undergraduate course at my university, which is not MIT.

      --
      "I've spent my whole life figuring out crazy ways to do things. It'll work." -- Montgomery Scott, "Relics"
    3. Re:very cool by edmudama · · Score: 1

      6.004 was awesome, both taking it and helping teach and debug other student's projects as a lab assistant. It's was a great introduction to the basic skills required to be a firmware engineer in today's job market, since you really got to figure out, clock by clock, how a CPU operates.

      --
      More data, damnit!
  5. not quite... by Sebastopol · · Score: 1, Insightful

    ...He still used a microprocessor in an integrated circuit. In college back in the 1980's some ubernerds built a 4004 with discrete transistors.

    But still, i give this person _HUGE_ props, breadboarding a circuit that complex is very, very, VERY time consuming amount of debug. it would drive most people insane, literally, it would break their brains to try and debug this.

    --
    https://www.accountkiller.com/removal-requested
    1. Re:not quite... by Dachannien · · Score: 2

      He still used a microprocessor in an integrated circuit.

      Really? Which one did he use?

    2. Re:not quite... by Osgeld · · Score: 1

      agreed, I have constructed a "computer" around a Z80, and there for a while ... wow. from countless hours tracing to out right fury as I yanked entire sections out with both fists and even in the end it never worked correctly

    3. Re:not quite... by DreamArcher · · Score: 1

      I was right there with you stabbing my wirewrap tool into the desk yelling "JUST WORK!!!"

    4. Re:not quite... by Darinbob · · Score: 3, Insightful

      It looks like he used actual 74xx series TTL chips to make the CPU. From the parts list he isn't doing microcoding, and isn't even using ALU or bit-slice MSI chips. It's the real thing.

    5. Re:not quite... by CODiNE · · Score: 1

      Oh good, that'll be next on my list of things to try and drive myself insane with.

      1) Hinton's cubes
      2) breadboarding an 8-bit computer

      Please let me know if you think of any other surefire ways to go nuts. Okay, now off to watch Brainstorm again.

      --
      Cwm, fjord-bank glyphs vext quiz
    6. Re:not quite... by Sebastopol · · Score: 1

      calm down: i meant to say he "just" used integrated circuits.

      --
      https://www.accountkiller.com/removal-requested
  6. Re:The mid 1970s called by kwoff · · Score: 1

    The mid 1990s also called, and they want their WebRing back.

  7. 2 Memes With One Stone by Scarletdown · · Score: 2, Funny

    I have to ask (since at the time I am writing this, no one else has done so yet)...

    Does it run Linux?

    And if it does, just imagine a Beowulf cluster of these things.

    --
    This space unintentionally left blank.
    1. Re:2 Memes With One Stone by CyberSaint · · Score: 1

      Came for this, left satisfied...

    2. Re:2 Memes With One Stone by Windwraith · · Score: 1

      It'd probably be quite the clumsy cluster. I can't wait for the smell of hot plastic when those wires start overheating.
      Correction: It'd probably be quite the smelly cluster. Like a tire factory.

    3. Re:2 Memes With One Stone by camperdave · · Score: 1

      Now, if he was running his website on this kludge, I'd be even more impressed.

      --
      When our name is on the back of your car, we're behind you all the way!
    4. Re:2 Memes With One Stone by datapharmer · · Score: 1

      still slow?

      --
      Get a web developer
  8. When can I get ... by damn_registrars · · Score: 1

    ... the portable version?

    --
    Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
  9. Can it store bitcoins? by turkeyfeathers · · Score: 1

    This computer is of no use if it can't store my bitcoin wallet.

  10. Homebrew CPU runs Minix by Anonymous Coward · · Score: 2, Interesting

    Here's one that running Minix: http://www.homebrewcpu.com/

  11. printer memory by e3m4n · · Score: 1

    dont forget to scavenge that printer memory from old dot matrix printers like the old days ;-)

  12. So its cool again? by Cute+Fuzzy+Bunny · · Score: 1

    I used to do this sort of thing 30-35 years ago. I remember building some of the first altair machines and hacking some cp/m code with Neil Colvin in his basement. I got together with a couple of guys to wire wrap one of the first (if not THE first) S100 bus graphics boards. We used to cobble up single board computers like this all the time, but they cost thousands of dollars to build. Good times, good times. Glad its the 'in' thing now, I feel like I know something ahead of the curve.

    1. Re:So its cool again? by jon_doh2.0 · · Score: 1

      Now we know your age, your user name seems creepy.

    2. Re:So its cool again? by Cute+Fuzzy+Bunny · · Score: 1

      Yes its true. I'm not cute, I'm not fuzzy, and believe it or not I'm not a bunny either. Thats the joke.

    3. Re:So its cool again? by jon_doh2.0 · · Score: 1

      Haha, nice. I felt mean as soon as i posted that, seems i missed the irony. Jokes on me.

  13. Minecraft by Nethemas+the+Great · · Score: 1

    If this was Minecraft someone would wander by, grab and handful of those pretty blue wires and rip them out.

    --
    Two of my imaginary friends reproduced once ... with negative results.
  14. Bad summary by ZyBex · · Score: 1

    263 lines of code? Really ??? How can you mix lines of code with video scanlines on your head?

    Those would have to be some long lines, anyway...

  15. Re:Obviously not real by turkeyfeathers · · Score: 1

    He could be a Chinese exchange student living in Massachusetts.

  16. Scratch? by rjhubs · · Score: 1

    If you wish to make a computer from scratch, you must first invent the universe.

    1. Re:Scratch? by Neil+Boekend · · Score: 1

      And then still someone is going to complain "it has been done before" and "you stole Jehova's idea".

      --
      Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
  17. Reminds me of the one by Jim+Buzbee · · Score: 4, Interesting

    Reminds me of the one my brother built here except my brother's computer runs Minux.

    1. Re:Reminds me of the one by ChrisMP1 · · Score: 1

      I saw that once before, and if I remember correctly, I said aloud, "That's fucking cool!" Really, that thing is amazing. I like that it actually runs Minix. Probably the most complete "homebrew computer" I have ever seen.

      --
      <sig>&nbsp;</sig>
  18. Wrong direction by iamacat · · Score: 2

    Everyone has right to their own hobbies, but think what can be accomplished with the same amount of labor and modern parts. Instead of making a CPU from hundreds of TTL gates, build a personal supercomputer from hundreds of ARM processors and custom operating system to effectively use that power for virtual reality or physics simulations. Hobbyists who has done this decades ago were futuristic not retro, creating devices that were not widely available, at least to private individuals.

    1. Re:Wrong direction by iamacat · · Score: 1

      Are 11 used first generation PS3s terribly expensive? They already run Linux, have 9 cores each for a total of 99 and support networking.

  19. Right direction by jabberw0k · · Score: 2

    It's the right direction for demonstrating that computers are based on discrete logical components, no matter how tiny and embedded in a chip; and the right direction for demonstrating that, given enough time and information, it would be possible to truly understand any digital device.

    Hmm, I wonder how many TTL chips I would need for a nice little PDP-11...

    1. Re:Right direction by not-my-real-name · · Score: 1

      Years ago, I had some youngsters ask what microprocessor our schools PDP-11/34 used. They had a tough time grasping that it didn't use a microprocessor at all and that the CPU was actually a couple of circuit boards. I think that they thought that a microprocessor was some sort of magical thing that couldn't be implemented in another fashion.

      Hmm, I wonder how many TTL chips I would need for a nice little PDP-11...

      I used to own a PDP-11/10. The CPU was two fairly large circuit boards. I also got a set of schematics when I got the computer. Sadly, they and the computer parted company with me a few moves back. I still miss it :-(

      Anyway, the number of TTL chips needed would depend on which PDP-11 you wanted to build and what level of integration you were willing to use. A few bit slice ALU chips could replace quite a few gate level chips.

      --
      un-ALTERED reproduction and dissimination of this IMPORTANT information is ENCOURAGED
    2. Re:Right direction by garyebickford · · Score: 1

      I don't recall very well, but wasn't the 11/34 the first PDP-11 using the Western Digital mpu chips? The ones that DEC tried to run WD out of business for, so they could buy the company cheaper than the chips?

      --
      It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
    3. Re:Right direction by garyebickford · · Score: 1

      (replying to self) - according to Wikipedia, the LSI-11 was first used in the 11/03, which was on the Qbus architecture, not the Unibus used by the 11/34. I stand corrected. :)

      --
      It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
    4. Re:Right direction by hamster_nz · · Score: 1

      It would take 1,389 flip-flops and 4,610 4-input look-up tables. So that's maybe 700+ 74LS74s and a few thousand 74LS series AND/OR/NAND/NOR/NOT chips. At 4mA per chip you will need a 5A or 10A power supply.

      But you could do it the easy way and configure an FPGA using http://opencores.org/project,w.11:

      The project contains a complete PDP-11 system: a 11/70 CPU with memory management unit, but without floating point unit, a basic set of UNIBUS peripherals (DL11, LP11, PC11, RK11/RK05), and last but not least a cache and memory controllers for SRAM and PSRAM. The design is FPGA proven, runs currently on Digilent S3BOARD and NEXYS2 boards and boots 5th Edition UNIX and 2.11BSD UNIX.

      A $150 FPGA board will be a lot cheaper than a drawer full of TTL. And a USB cable is a very cheap power supply.

      And you can have it up and running in a few nights.

  20. Not "from scratch"... by rthille · · Score: 1

    He wired up a bunch of ICs. For "From Scratch", google 'toaster from scratch...

    --
    Awesome furniture, accessories and cabinetry in Santa Rosa, CA: http://humanity-home.com/
    1. Re:Not "from scratch"... by Arlet · · Score: 1

      Or, as the late Carl Sagan said: "if you wish to make an apple pie from scratch, you must first invent the universe".

      You have to start somewhere, though.

  21. No microprocessor there by NixieBunny · · Score: 1

    You appear to be wrong. He built a minicomputer from logic chips. Look at the schematic - why would there be an instruction decoder if he used a microprocessor?
    I wonder why he didn't wire-wrap it. This is a crazy way to build a computer - thousands of blue wires, any one of which could fail with a loose connection at any time.

    --
    The determined Real Programmer can write Fortran programs in any language.
    1. Re:No microprocessor there by Sebastopol · · Score: 1

      my bad, i meant to say that he used "just" integrated circuits not a microprocessor.

      still, that's a big "just"

      --
      https://www.accountkiller.com/removal-requested
  22. Re:The mid 1970s called by Darinbob · · Score: 1

    This is one of the best web rings though. Some really cool systems in there. Snag is many of those pages are served by the actual homebrew CPUs themselves, so they could be a bit slow (oh no, they're being slashdotted!).

  23. relay computer by mbreeze · · Score: 2

    Another interesting computer built from electrical relays.

    1. Re:relay computer by Hal_Porter · · Score: 1

      I'd normally hesitate to do anything that drags the erudite discussions here off on a tangent, but look at this Nixie clock made out of Neon Ring Counters

      http://www.youtube.com/watch?v=F4v7IDIYiNQ

      --
      echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
  24. A few decades too late by nurb432 · · Score: 1

    in the old days doing things 'by hand' was the only way it got done. But i guess ill give him credit for the patience that it requires to do this sort of stuff. ( does bring back old memories however.. sore fingers, smell of burnt solder in the air.. )

    --
    ---- Booth was a patriot ----
  25. It's me, the creator. by Anonymous Coward · · Score: 1

    Yes, Jack Eisenmann. Some of you guys are overly critical/speculative of the project. I didn't make this machine to make money or make a "superior computer"; I did it just for fun. Also, I have just graduated from highschool, so it is kindof miraculous that I can do this at all. So just appreciate it as a crazy mess of wires that actually works. :)

    No, there is no microprocessor. The most complex chips in the machine are SRAM chips. You can see from the list on my site.

    Thanks to the supportive comments!

    1. Re:It's me, the creator. by barneythebigdog · · Score: 1

      WOW...who would believe a high school kid could do this...way to go!

    2. Re:It's me, the creator. by Boxtracod · · Score: 2

      I made an account just to emphasize the point: I, Jack Eisenmann, built the DUO Adept in highschool, and I have no formal education in electronics. I learned everything by experimenting with breadboards, getting tips from online users, and poking around Google.

    3. Re:It's me, the creator. by mrchaotica · · Score: 1

      Awesome job; now you should use it to bootstrap your own trustable compiler.

      --

      "[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz

    4. Re:It's me, the creator. by thePig · · Score: 1

      This is amazing. This article doesn't give enough credit to what you have done. This is unbelievable - There is no question that you are a genius - but I also really admire your patience - I cannot believe the amount of frustrating debugging that you would have to go through for this.

      I am a low level entrepreneur/inventor myself - and while I have nowhere near the intelligence and patience that you posses, I do have enough experience in this area to appreciate this. Study hard and become a great - you have the capability - just focus it enough.

      --
      rajmohan_h@yahoo.com
  26. Fun with ICs by tftp · · Score: 2

    He certainly had some fun building this. The wires are used probably because he wasn't sure that everything works right; it's much easier to rework a wire connection than an inner PCB trace.

    I suspect he is a strong amateur, but not a professional. A professional would design the whole thing in a simulator first, and once that works he'd implement it on a PCB (if not an FPGA.)

    I personally haven't built processors, but I built a few peripherals for PDP11/LSI11, all from discrete logic. And I serviced IBM 360/370 systems [long time ago] - they were built exactly this way, but were a bit more modular.

    1. Re:Fun with ICs by barneythebigdog · · Score: 1

      check the link to his You Tube page...he just finished high school...http://www.youtube.com/watch?v=qYvr0b8jqbg

  27. EHEM -From the creator. by Boxtracod · · Score: 2

    I somewhat dislike the Slashdot commenting system. So for the 3rd time, since I want to stand up for myself, to avoid having a "hidden" comment I am going to restate: I, Jack Eisenmann, built the DUO Adept in highschool, and I have no formal education in electronics. I learned everything by experimenting with breadboards, getting tips from online users, and poking around Google. I don't feel that the blurb does justice for my accomplishments.

    1. Re:EHEM -From the creator. by thatskinnyguy · · Score: 1

      As someone who had the same thing happen, let it go man. In 5 years you will be wondering how you had your head that far up your ass commenting on this and identifying yourself.

      --
      The game.
    2. Re:EHEM -From the creator. by mrchaotica · · Score: 1

      Oh, you made an account. See my other reply

      --

      "[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz

    3. Re:EHEM -From the creator. by jones_supa · · Score: 1

      Don't worry, we heard you. :) So, what's the next big thing?

      Someone above posted this idea, what do you think about it?

      Instead of making a CPU from hundreds of TTL gates, build a personal supercomputer from hundreds of ARM processors and custom operating system to effectively use that power for virtual reality or physics simulations.

    4. Re:EHEM -From the creator. by JeremyR · · Score: 1

      It is an impressive accomplishment, and you should be proud of that. It demonstrates initiative, patience, imagination and maybe a bit of ingenuity.

      There are some responses here that amount to "BFD" and you would do well to ignore those. There are others that put the scope of such a project in context, comparing it to what an undergrad student might do in a CS or EE class (and without much more experience or education than you have). I believe these responses are intended not to diminish what you've achieved, but merely to point out that it isn't rocket science (if you'll pardon the use of an old expression).

      So, while similar things have been done before, it's still a monumental undertaking, and the fact that you saw the project through to completion says a lot. Again, nice job. The world (or at least some of us geeks) will be interested to see what you come up with next...

      Cheers!

  28. IN SOVIET RUSSIA by spaceyhackerlady · · Score: 1

    In Soviet Russia computer wirewraps you.

  29. Re:Have fun troubleshooting... by PPH · · Score: 1

    So when the bomb squad can't figure out what it is, they'll radio the point man the instructions, "Cut the blue wire". And then he'll shit himself.

    --
    Have gnu, will travel.
  30. TTL computer from Electronics Australia by Ozoner · · Score: 2

    Very similar to the "Educ-8" TTL computer from Electronics Australia mag in 1974

    see http://en.wikipedia.org/wiki/File:EDUC-8_Microcomputer.jpg

    and http://www.sworld.com.au/steven/educ-8/

       

  31. Wrong analysis by Peter+(Professor)+Fo · · Score: 1
    Young brains at work with basic materials that are tedious to work with MAY result in mega-technological-breakthrough or not. As most of us here are concerned we left our machine code/assembler/etc behind us 20+ years ago so who are we to judge? The way 'progress' has worked means that a very fey possible choices have been followed. These may not have been the best.

    And while you're pooh-poohing 'wasted effort' in bare-metal computing ask yourself what proportion of 'programmer-man-hours' (rough term) end up being wasted at high-level modern day systems? And for those that are implemented that don't cause grief, how long do they last? Of course some pootle on quietly for a very long time, but many never hit the mainstream or if they do for a short while until revision or abandonment.

  32. Spend your time more wisely by Anonymous Coward · · Score: 1

    This guy's apparently in highschool. Honestly, as someone with a computer engineering degree designing hardware and software for a living, forget doing this shit at his age, go chase some girls and try to get laid.

  33. I created life from scratch by NicknamesAreStupid · · Score: 1

    Actually, lots of scratches on my back by my wife, who then carried our son to term. Does that count?

  34. Tanenbaum quote by kasperd · · Score: 1
    This story reminds me of a quote from one of Tanenbaum's books.

    In theory, after fully understanding this chapter, the reader should be able to go out and buy a large bag full of transistors and build this subset of the JVM machine. Students who successfully accomplish this task will be given extra credit (and a complete psychiatric examination).

    I'm not sure if the guy from this article qualifies, but it sounds like he is close.

    --

    Do you care about the security of your wireless mouse?
  35. Not enough memory? by Faulkner39 · · Score: 1

    Jack Eisenmann will never need more than 256 bytes of RAM.

  36. Building Turing machines from scratch by cpghost · · Score: 1

    In an alternate universe where I missed theoretical CS lectures, I wanted to build a (Universal) Turing Machine from scratch... but soon ran out of tape. Then I wanted to build a Register Machine from scratch, but ran out of memory before realizing that it was equivalent in power to the Turing Machine I couldn't build. Then I got hold of an Oracle (sadly not the company), but this Oracle-augmented machine STILL had limitations and couldn't compute EVERY imaginable function. Every time I wanted to showcase those machine, someone came with a diagonalized function that wasn't supported. Then I gave up building computers from scratch altogether.

    --
    cpghost at Cordula's Web.
  37. Not 263 lines of code by gedhrel · · Score: 1

    263 lines on the display. The article describing it gets it wrong, too, but there's an OS listing at the site.

  38. boot time by idji · · Score: 1

    I wish my laptop booted as fast as his computer!