Thread

1. geerlingguy · 1790997473 · focus · HN ↗

   So... at what point does someone re-create a 386 or 6501 but using only a motherboard, with no discrete circuits?

   1. Cieric · 1791000210 · focus · HN ↗

      Shouldn't that have already been do-able? I know the The MOnSter 6502 is a thing. The 386 I have no idea about though, that's to far out of my wheel house.

      <a href="https:&#x2F;&#x2F;monster6502.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;monster6502.com&#x2F;

      1. duskwuff · 1791002040 · focus · HN ↗

         A replica 386 would be impractically large - it&#x27;s got around 275k transistors, compared to the 3.5k in the 6502. At the same scale as the MOnSter 6502, that&#x27;d be about a hundred square feet of PCB.

         The number of layers isn&#x27;t even remotely close to being a constraint. The real i386DX was manufactured on a process which only supported two metal layers, and a PCB version isn&#x27;t subject to the same constraints as silicon.

         1. Cieric · 1791003680 · focus · HN ↗

            Interesting, thanks for the info.
         2. geerlingguy · 1791003694 · focus · HN ↗

            But in terms of rearranging the stack vertically; is that a possibility?

            1. duskwuff · 1791005280 · focus · HN ↗

               Components like transistors usually have to go on the surface of a PCB. (While there are techniques for embedding components in a PCB, they&#x27;re extraordinarily expensive and would not be feasible for a project like this one.)
            2. snek_case · 1791026459 · focus · HN ↗

               Probably not, because transistors produce some heat, and you can&#x27;t really sandwich surface mount transistors between PCB layers either. You could vertically stack PCBs with some spacing, however, but then normal PCBs will do the job.

               1. rcxdude · 1791068424 · focus · HN ↗

                  It is possible to embed components in the middle of a pcb, but it&#x27;s a pretty specialist process (read: a pain in the neck because it interleaves the pcb fabrication and assembly stages, making both steps more complicated).
         3. snek_case · 1791026530 · focus · HN ↗

            The ARM1 was a 32-bit CPU and it only had about 25K transistors so that one might be fair game if you can bring the components a little bit closer together, but you don&#x27;t need a fancy PCB for that, and I guess the clock speed would need to be very slow if it&#x27;s several square feet in size.

Unofficial Hacker News client; not affiliated with Y Combinator.