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From: werner@aecom.UUCP (Craig Werner)
Newsgroups: net.micro.pc,net.micro.atari,net.micro.mac
Subject: Re: DRI/GEM ;CDC/1s complement
Message-ID: <1945@aecom.UUCP>
Date: Tue, 15-Oct-85 00:25:12 EDT
Article-I.D.: aecom.1945
Posted: Tue Oct 15 00:25:12 1985
Date-Received: Wed, 16-Oct-85 07:01:32 EDT
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Organization: Albert Einstein Coll. of Med., NY
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> When I was first learning about computers (around '68) I asked a teacher
> why it was that CDC machines used 1's complement arithmetic.  He replied
> that IBM held hefty patents on two's complement algorithms that Control
> Data did not want to pay for.  I have no idea whether or not this story 
> is true,
> Henry M. Halff 

	This may be closer to the truth:  Someone was once describing how the
Cray machines used One's complement because Seymour Cray could wire it a 
certain way to get a speed advantage.
	Cray started at CDC, so if the above is true, it may explain the CDC
architecture without having to invoke patent rights.

	Speaking of patent rights, the original Mauchly/Eckert ENIAC patent,
one of, if not, the longest in US history, patented Digital Logic, binary
AND,ORs, adders, the works.   It proved possible to circumvent, but kept
lawyers busy for a decade.

-- 

				Craig Werner
				!philabs!aecom!werner
              "When I was your age, I did it for half an hour every day."