Systems Concepts SC-4 computer

[Lars Brinkhoff]

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:
http://people.csail.mit.edu/saltzer/Multics/MHP-Saltzer-060508/filedrawers/141.graphics-system/Scan%203.PDF