Digital Equipment Corporation M8186 LSI-11/23 CPU board

    This is the actual "brains" of the pdp11/23 in my collection. The microprocessor proper is the large IC in the centre of the board with two gold covers on it. The master clock crystal is just above it.

    When I make remarks of dual height, quad height, and hex height boards, I'm using DEC's parlance for the number of "finger connection planes" used on a given card. This board sports two, hence it classes as a "dual height" card; those with 4 are "quad height", and so on.

    There's been a certain amount of noise lately that the Pentium P6 is one of the first microprocessors to use two separate ICs in a single carrier. While not legible on the Web picture, the clock crystal on this board carries a handwritten "test and check" date of "Sep 10, 1988" (9-10-88 is the exact note; I imagine that the board is somewhat older). The 11/23 itself was introduced by DEC in 1979. It looks like there's really nothing new after all.

    The three socket areas directly below the microprocessor IC proper are for various expansion options such as memory management, EIS, and FIS. This individual obviously has none of the options. Oh, well....

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