Systems Concepts SC-4 computer

Eric Moore mooreericnyc at
Mon Feb 15 09:07:52 CST 2021

You can see some info on the systems (gould SEL) concept line here, but
looking at that PDF, systems concepts was something different.


On Mon, Feb 15, 2021, 4:47 AM Lars Brinkhoff via cctalk <
cctalk at> wrote:

> Anyone ever heard of the Systems Concepts SC-4 computer?
>  "This is an two's-complement 18-bit machine, with 16 general registers
>   and a 16 level priority interrupt system.  Its programming ascpects
>   are explained in great detail in the SC-4 Reference Manual, of which a
>   draft is enclosed.  Below are times for some typical instructions.
>   Add word on stack (not top word) to general register      1.5 us
>   Multiply general register by memory word                  6.2 us
>   Jump                                                      750 ns
>   Push and Jump                                             1.5 us
>   Compare Immediate                                         750 ns"
> From page 6 here:

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