On Wednesday, 23 September 2020 at 22:33:38 -0400, Clem Cole wrote:
> Dave: Seymour used ones complement on the 3000 and 6000 series.
> Maybe there?   The primary HLLs I used on the CDC boxes were FTN and
> Pascal, but I would not be surprised if that was were you saw it.

I think most of the bigger pre-IBM 360 machines used one's complement.
Didn't the PDP-10?  I knew it not only from the CDC 3200 and 3800, but
primarily from Univac (1108 and 494).  The Univac techies explained to
me that the primary arithmetic function was subtraction; addition was
subtracting the complement.  And that worked faster with one's
complement.