11 Jun
2026
11 Jun
'26
8:09 a.m.
On Jun 11, 2026, at 12:04 AM, Ethan Dicks via cctalk
<cctalk(a)classiccmp.org> wrote:
On Wed, Jun 10, 2026 at 10:44 PM Gavin Scott via cctalk
<cctalk(a)classiccmp.org> wrote:
A lot of systems used one's complement through the 1960s. I'm not really sure
why. Not just for integers but floating point also (as on the CDC mainframes, and around
the same time the Electrologica X8 with a slightly different approach).
paul
RAMAC refers to a complete computer system that
implements the "Random
Access Method of Accounting and Control", such as the IBM 305 RAMAC of
which the IBM 350 disk storage unit is a *component*.
Back at one of my early jobs in the 80s, the owner told me a story
from when his dad worked at Columbus Coated Fabric (before they were
bought by Borden Chemical, the makers of Elmer's Glue). As the story
goes, CCF was either the first or second big company in Columbus to
buy a computer, an IBM 305 RAMAC, specifically for payroll. It was
then that I learned about one's-complement machines and 'negative
zero'.