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From: baum@apple.UUCP (Allen J. Baum)
Newsgroups: comp.arch
Subject: Re: Architecture behind early electronic calculators
Message-ID: <1410@apple.UUCP>
Date: Thu, 30-Jul-87 20:55:08 EDT
Article-I.D.: apple.1410
Posted: Thu Jul 30 20:55:08 1987
Date-Received: Sat, 1-Aug-87 15:25:37 EDT
References: <1893@kitty.UUCP>
Reply-To: baum@apple.UUCP (Allen Baum)
Organization: Apple Computer, Inc.
Lines: 33

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[]
>In article <1893@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
>
>	While I have always had a keen interest in the history and development
>of computers, and have collected and read many books on the topic, there is
>one area which I have never seen mentioned: the early electronic calculator.
>By "early", I am referring to 1966 and prior years.
>	My first electronic calculator experience was a Wang scientific
>calculator in 1965.
>Did they operate using some form of stored program control, and hence
>a "software" algorithm for these exponential, log and trig functions?
>Or did they have dedicated hardware logic for each mathematical function?

These are my interests as well. As I recall, the Wang's did have some
kind of programmed or microcoded control. I don't recall which
algorithm was used (Taylor-series, continued fraction, etc.), but I
believe it was different from what HP used on their HP9100. The
HP9100 was an amazing machine, and resulted in my first programming
experience. Internally, it was a highly microcoded bit serial,
decimal machine. It did not have an adder! All it could do is
increment or decrement a decimal digit! It counted one down, and
another up until the first equalled 0, and then went on to the next
digit to perform an addition (similarly for subtraction).
Multiplication, and all the CORDIC routines it used for the log, exp,
and [hyper][arc]trig functions. The HP65 handheld programmable
almost exactly duplicated its functions years later.

The microprogram control was an inductively coupled 14-layer PC
board!  The Russians actually copied this, ROM & all. It must have
been fun to peel apart those 14 layers.....

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