5 ms·

Good luck with that. Just making glass is going to take you a while. Making semiconductors at a scale that you can start thinking of building a working comput

by 0x12 15y ago

Good luck with that. Just making glass is going to take you a while. Making semiconductors at a scale that you can start thinking of building a working computer will take you quite a bit longer. It's simple in principle. It would be far easier to stuff a bunch of people in rooms with paper (assuming you could make that) and pencils (ditto) and have them execute your program.

zerostar07 15y ago
but that's how it started! http://xkcd.com/505/ http://xkcd.com/505/
mechanical_fish 15y ago
Among other things, "how to make a semiconductor" is like that joke about how to make a million dollars: "First, you take a million dollars..." You're going to spend years just bootstrapping your metal refinery to the point where you can bootstrap your machine shop to the point where you can bootstrap your chemical industry to the point where you can produce undoped silicon of sufficient purity to make a decent integrated circuit. Sure, maybe you can slap together a handful of cheesy transistors to rival the first-ever transistor (Google up the picture of the first transistor; it's hilarious; you can practically smell the hot glue wafting from that picture) but it takes a bunch of transistors to make a computer, and you'd probably like your computer to get through three whole clock cycles before melting. You might actually be better off just recapitulating history by starting with vacuum tubes. You'll need to master glassblowing and vacuum pumps to build semiconductors anyway, and tubes have lots of handy uses. (You could build an oscilloscope, which you will also need.) But you'll need to bootstrap your metal wire industry (generators aren't that hard to make if you can get hundreds of continuous feet of insulated wire...) and note that you'd better be very careful until you've had time to bootstrap your plastics industry; there are scary stories from the early days of TV when they had high-voltage circuits but nothing to insulate the wires with but varnish and paper...
- prodigal_erik 15y ago
  Jeri Ellsworth managed to make transistors in a pottery kiln, starting with modern wafers. She said it took three years of research and interviewing graybeards who were working on it in the 1970s. Makes me hope she wrote that stuff down.
  - mechanical_fish 15y ago
    That sounds about right. But "build a transistor, given a wafer of pure undoped silicon" really is isomorphic to that joke about using a million dollars to make a million dollars.
  - 0x12 15y ago
    The wafer is the hard part. That's why I suggested making glass first, it's a good primer on the kind of gear that might one day lead up to the tooling you'll need to make silicon pure enough to make a transistor. You'd be much better off choosing a road that leads via relays, that's just metalworking and some coating. Vacuum tubes would still be an order of magnitude easier than silicon. Think sandy beach + pit mine, before you turn that into a working transistor you're going to be busy for a while.
    - JoshTriplett 15y ago
      > You'd be much better off choosing a road that leads via relays One Portland State University professor built a relay computer, with an ALU: http://web.cecs.pdx.edu/~harry/Relay/ http://web.cecs.pdx.edu/~harry/Relay/ Quite impressive to see it in action.
      - 0x12 15y ago
        Thank you for that link. I took the liberty of re-posting it separately, it is one of the coolest things I've ever seen built. Besides the memory (and that would just add another couple of 10's of thousands of relays for a usable machine) that looks like the shortest direct path between 'man on a beach' and having a working automatic computer with a practical degree of reliability.

by 0x12 15y ago

zerostar07 15y ago

but that's how it started! http://xkcd.com/505/ http://xkcd.com/505/

mechanical_fish 15y ago

Among other things, "how to make a semiconductor" is like that joke about how to make a million dollars: "First, you take a million dollars..." You're going to spend years just bootstrapping your metal refinery to the point where you can bootstrap your machine shop to the point where you can bootstrap your chemical industry to the point where you can produce undoped silicon of sufficient purity to make a decent integrated circuit. Sure, maybe you can slap together a handful of cheesy transistors to rival the first-ever transistor (Google up the picture of the first transistor; it's hilarious; you can practically smell the hot glue wafting from that picture) but it takes a bunch of transistors to make a computer, and you'd probably like your computer to get through three whole clock cycles before melting. You might actually be better off just recapitulating history by starting with vacuum tubes. You'll need to master glassblowing and vacuum pumps to build semiconductors anyway, and tubes have lots of handy uses. (You could build an oscilloscope, which you will also need.) But you'll need to bootstrap your metal wire industry (generators aren't that hard to make if you can get hundreds of continuous feet of insulated wire...) and note that you'd better be very careful until you've had time to bootstrap your plastics industry; there are scary stories from the early days of TV when they had high-voltage circuits but nothing to insulate the wires with but varnish and paper...

prodigal_erik 15y ago
Jeri Ellsworth managed to make transistors in a pottery kiln, starting with modern wafers. She said it took three years of research and interviewing graybeards who were working on it in the 1970s. Makes me hope she wrote that stuff down.
- mechanical_fish 15y ago
  That sounds about right. But "build a transistor, given a wafer of pure undoped silicon" really is isomorphic to that joke about using a million dollars to make a million dollars.
- 0x12 15y ago
  The wafer is the hard part. That's why I suggested making glass first, it's a good primer on the kind of gear that might one day lead up to the tooling you'll need to make silicon pure enough to make a transistor. You'd be much better off choosing a road that leads via relays, that's just metalworking and some coating. Vacuum tubes would still be an order of magnitude easier than silicon. Think sandy beach + pit mine, before you turn that into a working transistor you're going to be busy for a while.
  - JoshTriplett 15y ago
    > You'd be much better off choosing a road that leads via relays One Portland State University professor built a relay computer, with an ALU: http://web.cecs.pdx.edu/~harry/Relay/ http://web.cecs.pdx.edu/~harry/Relay/ Quite impressive to see it in action.
    - 0x12 15y ago
      Thank you for that link. I took the liberty of re-posting it separately, it is one of the coolest things I've ever seen built. Besides the memory (and that would just add another couple of 10's of thousands of relays for a usable machine) that looks like the shortest direct path between 'man on a beach' and having a working automatic computer with a practical degree of reliability.