I often think whether I could (or should) try to build something like this out of a cluster of SBCs, hooked to a bigger board by the GPIO pins and lighting LEDs depending on CPU core activity. 16 boards with 32 cores each would require 8 RPi 4's per board, plus the network cables coming out the back and a total of 64 nodes.
It'd probably be cleaner to use compute modules such as the RPi 4 CM or the Pine64 SOPINE because they pass ethernet and GPIO via the board connectors and wouldn't require more than one ethernet port per board (provided the board has its own switch) but I have no idea of how to design a switch, much less misusing the bits and pieces of one where the network cables are traces on a PCB.
Either that, or have 32 Octavo SoMs, which would allow two separate networks per board, but I'd still need to design the switches (and I have no clue as to how to do that beyond "try to make the traces of equal length").
At least the "neck" of the CM-2a has space for a very large and, presumably, quiet fan.
It'd probably be cleaner to use compute modules such as the RPi 4 CM or the Pine64 SOPINE because they pass ethernet and GPIO via the board connectors and wouldn't require more than one ethernet port per board (provided the board has its own switch) but I have no idea of how to design a switch, much less misusing the bits and pieces of one where the network cables are traces on a PCB.
Either that, or have 32 Octavo SoMs, which would allow two separate networks per board, but I'd still need to design the switches (and I have no clue as to how to do that beyond "try to make the traces of equal length").
At least the "neck" of the CM-2a has space for a very large and, presumably, quiet fan.
http://www.corestore.org/cm2a.htm