Mechanical calculators (was: Re: *updating* 8088's)

[M H Stein]

-------Original Message:
Date: Sun, 02 Dec 2007 23:06:02 -0800
From: "Chuck Guzis" <cclist at sydex.com>
Subject: Re: Mechanical calculators (was: Re: *updating* 8088's)

On 3 Dec 2007 at 1:46, M H Stein wrote:

>> (Chuck: change the colour, remove the cabinet on the left and put it on tubular legs
>> and you've got the picture you're looking for - remove the alpha keyboard for one
>> of the older numeric-only models ;-)

>How about the National Class 3000 from 1929? One can be seen on the 
>page numbered 140 in this very interesting document from Portugal:

>http://www3.dsi.uminho.pt/memtsi/docs/guia_exposicao_ilustrado.pdf

>Cheers,
>Chuck
-----
Well, the Burroughs F styling was a _little_ more modern and the Sensimatic
program panels were a Burroughs trademark, but yes, that's the idea (even the
flip-up table for the ledger tray on the left). The one in the eBay ad that Arno
mentioned is a fairly late model F with the beige and blue colour scheme; the
older ones were dark brown.

Some nice pictures on that Portuguese site; even the 517 interpreter that got 
that other thread going.

Incidentally, Sensimatic referred to the way the program pins were "sensed;" 
the pins were different lengths which determined the operation to be performed 
(add/subtract/print/etc.) and different pin locations determined the register 
number or the accumulator (sound familiar?). A set of sensing pins would rise 
up to measure the length of the program pins, and the keyboard also had 
"function keys" (called OCKs - Operator Control Keys) for different options
(normal entry, error correction, etc.)

A program would consist of steps like "Load A (from keyboard) (INP 01), 
"LD R1, 2 and 3 from A," "SUB A from R5&6," "Punch A (OUT 2)," "IF OCK3
then SKIP (JMP) to Step12," etc., all done mechanically with gears, levers 
and springs of course. Programming was done with a nibbling tool, a tray 
of numbered different length pins and a screwdriver.

Wouldn't you love to have 20 registers today, and the ability to load/store
more than one simultaneously? Mind you, that was also the entire memory 
until electronic versions came along...

And of course they usually had colour printers ;-) (Red & black ribbons).

BTW, AFAIK some Teletypes used the same type "box" as the typing Sensimatic 
that Arno is talking about. Think I still have one of those somewhere as well.

m