COOL
On Monday, May 30, 2022, 06:57:59 AM EDT, Seymour J Metz <[email protected]>
wrote:
I would expect to see finite difference calculations in the 1960s on a 60x or
610 rather than a 407, although the Manhattan Project did do calculations on a
room full of tabulators.
Displaying operational registers using, e.g., Nixie tube, was quite common for
decades. I know of machines that displayed individual bits and machines that
displayed octal digits; I suspect that there were machines that displayed
decimal digits.
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
________________________________________
From: IBM Mainframe Discussion List [[email protected]] on behalf of
Paul Gilmartin [[email protected]]
Sent: Sunday, May 29, 2022 8:45 PM
To: [email protected]
Subject: Re: Tabulating Machines (was "... z114")
On Sun, 29 May 2022 17:11:33 -0700, Charles Mills wrote:
>I have never programmed a Tab machine but here is what I know.
>
>The addition and so forth was purely mechanical. Anyone remember old-fashioned
>mechanical adding machines? Picture a wheel with ten cogs on it numbered 0
>through 9. Let's say it is indicating 5. If you turn it three clicks it is now
>indicating 8. Voila! 5 + 3 = 8. Let's say you turn it three additional clicks.
>It is now reading 1, and on the way from 9 to 0 it poked the wheel to its left
>one position. 8 + 3 = 11.
>
>Yes, the plug board's purpose was to hold the wires ...
>
Mid 1960s. A colleague told me (third hand story) of someone who had programmed
a 407(?) to extract second differences -- differences of successive differences
of
successive inputs -- discrete second derivative.
The Numeric Analysis Center of the University of Colorado had an open-access
SCM electronic calculator. Its registers were continuously visible on a CRT
display in stroked characters. I could watch it extract a square root using
Newton's Method in 44 seconds. Beside it was a mechanical Friden with cogwheel
registers continuously visible. I could watch it extract a square root by
subtracting
successive odd numbers in 22 seconds.
--
gil
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