On 08/22/2015 04:23 PM, Sean Conner wrote:
   For my own morbid curiosity, and because it came up on another mailing
list I'm on [1], what machines commercially avaialble were sign magnitude
and one's complement?  Every machine I've encountered was two's complement
(okay, IEEE 754 [2] is a sign magnitude format but I'm talking about integer
implementations here, not floating point).  I've only found reference to one
sign magnitude computer (the IBM 7090, release in 1959) and a few one's
complement machines (mostly the PDP series from DEC).


The LINC (Laboratory INstrument Computer) was one's complement, with a 12-bit word. Several derivative machines were the same. The most confusing, of course, were the LINC-8 and PDP-12, which had the PDP-8 instruction set with two's complement, and the LINC instruction set, with one's complement, all in the SAME machine. SHEESH!

Jon

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