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Cake day: June 14th, 2023

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  • I did a course in photolithography, including a lab session where I literally made an unpackaged ASIC by hand, using technology that was current in the mid 90s. Etching silicon and doing photolithography is completely out of the reach for a hobbyist, even from scratch, even with 30 year old technology. Reusing a random chip and adding to it is simply impossible.

    Essentially, you are looking at the following problems with simply creating a new chip:

    1. Need access to a large clean room
    2. Need a furnace that can heat up your silicon wafers to silly temperatures in order to do doping via sputtering.
    3. Need chemical handling equipment, including safety gear required for handling hydrofluoric acid.
    4. Need a photolithography device with your designs.
    5. Need to cut, test, and package chips after they are created.

    And the additional problems with using an existing chip:

    1. Need to decapitate the existing chip and remove it from the package.
    2. Need to work with a single already sliced chip instead of a wafer.
    3. A completed chip will have metal vias that cover a large portion of the silicon, you would need to perform your chemical etching without harming these or any silicon that has been used.
    4. Generally, Asics don’t have wasted space, but simply larger components. There would be no footprint available for your design, even if your hobbyist tooling was smaller than the one used for the components, which is probably wouldn’t be.






  • I am a bit late to this party, but I thought I’d piggy back on your comment to halfway address it using math.

    We want to run data centers cool. This means keeping the center itself as close to 20°C as possible.

    If we lose our convection and conduction then our satellite can only radiate away heat. The formula governing a black body radiator is P = σAT^4. We will neglect radiation received, though this is not actually a negligible amount.

    If we set T = 20°C = 294K. Then we have the relationship of P/A = 423.6 W/m^2

    According to an article I found on the Register from this April:

    According to Google, the larger of the two offered pods will consume roughly 10 megawatts under full load.

    This would imply a surface area of at minimum 23600 m^2 or 5.8 acres of radiator.

    I don’t know how large, physically, such a pod would be. But looking at the satellite view of a google data center in Ohio that I could find, the total footprint area of one of the large building of their data centers is ballpark in that range. I don’t know how many “pods” that building contains.

    So it’s not completely outside of the realm of possibility. It’s probably something that can be engineered with some care, despite my earlier misgivings. But putting things in orbit is very expensive, and latency is also a big factor. I can’t think of any particular practical advantages to putting this stuff into orbit other than getting them out of the jurisdiction of governments. (Not counting the hype and stock song and dance from simply announcing you’re going to set a few billion dollars on fire to put AI into space.)