IIRC MIT modified the early PDP-10s to have demand paging support for running ITS, so even Maclisp wants many kilo-words of address space. Yes, and then convin

IIRC MIT modified the early PDP-10s to have demand paging support for running ITS, so even Maclisp wants many kilo-words of address space. Yes, and then convinced ARPA to fund the purchase of 1 megabyte (MiB, of 9 bit bytes) of core memory, a full address space. At the edge of the state of the art back then, many people said it couldn't be made, and I seem to remember coming across some stories about it being quite difficult to get operating. When I showed up in 1979 it was referred to with names like the "crufty", it wasn't all that reliable. Those were original formula KA10s. Afterwards came a KI 10 processor I don't know much about, none were bought by MIT. For MIT-MC, David Moon modified the KL10 firmware to do ITS style paging. Developing that KA10 paging unit must have been wild; a student run computer center I started inherited the hardware, and the schematics were fascinating, especially since they were from before there was a standard for logic gates. Instead, they were represented by boxes with the logic function marked in an upper corner. A friend of mine (who I recruited into LMI and who put several "100 hour weeks" into successfully debugging and finishing their LAMBDA processor) noticed that in some cases the state of a gate, or perhaps a flip-flop?, was changed by hitting its output hard. Gates were sufficiently expensive, and the designers knew the hardware sufficiently well; you can see a picture of one 9 transistor Flip-Chip here: https://en.wikipedia.org/wiki/Flip_Chip_(PDP_module) https://en.wikipedia.org/wiki/Flip_Chip_(PDP_module)