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From: cy@ashtate (Cy Shuster)
Newsgroups: comp.arch
Subject: Re: Architecture behind early electronic calculators
Message-ID: <322@ashton.UUCP>
Date: Wed, 5-Aug-87 13:35:49 EDT
Article-I.D.: ashton.322
Posted: Wed Aug  5 13:35:49 1987
Date-Received: Sat, 8-Aug-87 10:43:21 EDT
References: <1893@kitty.UUCP> <1410@apple.UUCP>
Reply-To: cy@ashtate.UUCP (Cy Shuster)
Distribution: world
Organization: Ashton-Tate, Torrance, CA
Lines: 24
Keywords: Wang calculator
Summary: The easy way to learn assembler!

That Wang calculator, with nixie tube display ("readout"!), was the first
machine I ever programmed, too. It used PortaPunch cards, and had a card
reader kind of like a vertical waffle iron: a latch let a hinged side flop
open, you insert card, and close it back up.

Aside from fond nostalgia, what was amazing to me about the machine was the
nature of the programming language. The machine itself was just a large,
floating point calculator, with four memory locations. The punch cards
simply had a code to represent each key on the keyboard! The display was,
of course, the accumulator -- and hitting the +M1 key was merely a Store
instruction. Constants were entered by, obviously, just hitting the number
keys.

There must have been a few extensions to allow real programs: a jump
instruction, for example. And I think there was even a way to allow input
of variables from the keyboard. But I still think that the calculator
analogy -- where an op code is just a keyboard function key -- is very
apt when trying to teach people assembler language.

I still miss the 1401, though, with variable word lengths and decimal
arithmetic! *Surely* there must be an Autocoder emulator for the PC out
there somewhere? If I get a card reader, I can put my PC on it!!

--Cy--      ...!seismo!scgvaxd!ashtate!cy    (UUCP)