10 ms·

As so happens, an article in the "popular press" totally misses the point. This is about the "Megaprocessor" - a CPU built entirely from discrete components.

As so happens, an article in the "popular press" totally misses the point. This is about the "Megaprocessor" - a CPU built entirely from discrete components. It's an amazing project, superbly executed, and submitted/discussed here on HN many times. You can see some of the previous submissions by using this search: https://hn.algolia.com/?query=megaprocessor&sort=byDate&dateRange=all&type=story&storyText=false&prefix&page=0 https://hn.algolia.com/?query=megaprocessor&sort=byDate&date... Recent submissions haven't had much discussion, but it deserves it. The testing and verification processes alone are fascinating - just how do you test something like this? Amazing project.

StavrosK 10y ago
My thoughts exactly. This guy built an entire computer, complete with CPU, ALU, memory, storage, etc from transistors, and the article just says it plays Tetris? Sure, it was going to run some program, but that's missing the point.
- stephengillie 10y ago
  It's as impressive as someone building a dune buggy by welding axles onto steel tubes and making their own engine and transmission mounts. Quite a feat of engineering, but not really pushing the bounds of known science. And with limited utility.
  - mrob 10y ago
    It's more like building that dune buggy, including the engine, entirely out of glass. It's not very useful for driving, but you can see exactly how everything works.
    - hatsunearu 10y ago
      More like transparent Legos. Discrete transistor circuits have terrible switching characteristics.
- gens 10y ago
  Many people build computers of varying complexities, but they usually use IC-s from the 4000 and 7400 series. These IC-s are mostly simple things, like NAND gates, adders and such (there are some complex ones). Making discrete equivalents of those IC-s is rather easy, especially with modern high speed low capacitance FET-s. I am impressed by this computer because it is verbose and thus educational.
  - TheOtherHobbes 10y ago
    Building a few gates on a small board is easy. Building a complete computer the size of a room isn't easy at all, because the connections between the elements have to be active transmission lines, and Vcc and GND still have to be clean enough to avoid spurious switching. There's a whole order of magnitude of extra design pain involved in building something that big, including LEDS in all the elements, and making it run fast enough not to be completely useless.
    - kyberias 10y ago
      Do you think this particular contraption is not useless?
      - laumars 10y ago
        It's not useless, it plays Tetris.
    - gens 10y ago
      Most used, and thus cheapest, transistor BC 639 is 100MHz (or 50MHz, i had a beer). Cheapest MOSFET is much faster then that. The Megaprocesor is 20kHz and the creator clearly states that it is for educational purposes. While on that topic; i will read the docs and watch the videos for educational purposes. ;)
jgrahamc 10y ago
As so happens, an article in the "popular press" totally misses the point. As it happens I know Zoe (who wrote this) very well and would be happy to pass on constructive suggestions on what folks would like to see in this article (and other tech. articles from the BBC).
- FussyZeus 10y ago
  I'd be surprised if Zoe picked her title, but that's a big point: > Huge home-built computer used for Tetris This makes it seem like the guy just wanted to play Tetris and took an extremely roundabout way to do it, where in fact he built the thing specifically to show the insane complexity we all carry around in our pockets and take for granted (I include myself in that statement 100%). Modern computers are nothing short of an engineering marvel and something like this, which is only a millionth as powerful and not capable of nearly as much built from scratch takes up an entire room. It reminds me a lot of that photo from not terribly long ago showing an Air Force crew unloading a 50 MB hard drive that was roughly the size of a walk in freezer. A good comparison would be someone who built their own aircraft to demonstrate how insanely complex an aircraft is, and then the news story about it says "Local Man Builds own Plane to jump down to Florida for a Burger."
- qq66 10y ago
  I would have appreciated a greater emphasis about the fact that a modern computer is made out of invisible transistors and that this is a fully discrete but working model, like a large cutaway steam engine in a science museum. Here, I'll take a wild stab: "You may have heard that computer processors consist of billions of transistors crunching through 0's and 1's. But what is actually happening inside these processors? A man has recently build a computer out of individual transistors, the components that control electric currents to perform computations. Instead of using one chip with billions of transistors, he has used individual transistors wired together, allowing him to visualize the individual computing structures and the electric currents that flow through them. His completed computer has "only" 40,000 transistors, which is just enough to play a game of Tetris, but he hopes that the relative simplicity of this computer, as compared to a modern smartphone, can help educate the public on how computers actually work."
empath75 10y ago
I've actually had this idea for a while now of creating snap-together redstone-like (from minecraft) cubes. Each would generate a signal, unless it's receiving a signal from a neighbor, making each one a NOT gate. You wouldn't literally build it with a transistor per block, they could have some fairly complicated logic inside with led's showing where the signal is going and so forth. You'd set each side to be input or output with a switch, and you could have different types of blocks (light or sound detectors, for example), or ones with usb ports for power/output, etc.

StavrosK 10y ago

My thoughts exactly. This guy built an entire computer, complete with CPU, ALU, memory, storage, etc from transistors, and the article just says it plays Tetris? Sure, it was going to run some program, but that's missing the point.

stephengillie 10y ago
It's as impressive as someone building a dune buggy by welding axles onto steel tubes and making their own engine and transmission mounts. Quite a feat of engineering, but not really pushing the bounds of known science. And with limited utility.
- mrob 10y ago
  It's more like building that dune buggy, including the engine, entirely out of glass. It's not very useful for driving, but you can see exactly how everything works.
  - hatsunearu 10y ago
    More like transparent Legos. Discrete transistor circuits have terrible switching characteristics.
gens 10y ago
Many people build computers of varying complexities, but they usually use IC-s from the 4000 and 7400 series. These IC-s are mostly simple things, like NAND gates, adders and such (there are some complex ones). Making discrete equivalents of those IC-s is rather easy, especially with modern high speed low capacitance FET-s. I am impressed by this computer because it is verbose and thus educational.
- TheOtherHobbes 10y ago
  Building a few gates on a small board is easy. Building a complete computer the size of a room isn't easy at all, because the connections between the elements have to be active transmission lines, and Vcc and GND still have to be clean enough to avoid spurious switching. There's a whole order of magnitude of extra design pain involved in building something that big, including LEDS in all the elements, and making it run fast enough not to be completely useless.
  - kyberias 10y ago
    Do you think this particular contraption is not useless?
    - laumars 10y ago
      It's not useless, it plays Tetris.
  - gens 10y ago
    Most used, and thus cheapest, transistor BC 639 is 100MHz (or 50MHz, i had a beer). Cheapest MOSFET is much faster then that. The Megaprocesor is 20kHz and the creator clearly states that it is for educational purposes. While on that topic; i will read the docs and watch the videos for educational purposes. ;)

jgrahamc 10y ago

As so happens, an article in the "popular press" totally misses the point. As it happens I know Zoe (who wrote this) very well and would be happy to pass on constructive suggestions on what folks would like to see in this article (and other tech. articles from the BBC).

FussyZeus 10y ago
I'd be surprised if Zoe picked her title, but that's a big point: > Huge home-built computer used for Tetris This makes it seem like the guy just wanted to play Tetris and took an extremely roundabout way to do it, where in fact he built the thing specifically to show the insane complexity we all carry around in our pockets and take for granted (I include myself in that statement 100%). Modern computers are nothing short of an engineering marvel and something like this, which is only a millionth as powerful and not capable of nearly as much built from scratch takes up an entire room. It reminds me a lot of that photo from not terribly long ago showing an Air Force crew unloading a 50 MB hard drive that was roughly the size of a walk in freezer. A good comparison would be someone who built their own aircraft to demonstrate how insanely complex an aircraft is, and then the news story about it says "Local Man Builds own Plane to jump down to Florida for a Burger."
qq66 10y ago
I would have appreciated a greater emphasis about the fact that a modern computer is made out of invisible transistors and that this is a fully discrete but working model, like a large cutaway steam engine in a science museum. Here, I'll take a wild stab: "You may have heard that computer processors consist of billions of transistors crunching through 0's and 1's. But what is actually happening inside these processors? A man has recently build a computer out of individual transistors, the components that control electric currents to perform computations. Instead of using one chip with billions of transistors, he has used individual transistors wired together, allowing him to visualize the individual computing structures and the electric currents that flow through them. His completed computer has "only" 40,000 transistors, which is just enough to play a game of Tetris, but he hopes that the relative simplicity of this computer, as compared to a modern smartphone, can help educate the public on how computers actually work."

empath75 10y ago

I've actually had this idea for a while now of creating snap-together redstone-like (from minecraft) cubes. Each would generate a signal, unless it's receiving a signal from a neighbor, making each one a NOT gate. You wouldn't literally build it with a transistor per block, they could have some fairly complicated logic inside with led's showing where the signal is going and so forth. You'd set each side to be input or output with a switch, and you could have different types of blocks (light or sound detectors, for example), or ones with usb ports for power/output, etc.