The dual paper tape readers were used to provide an "instruction"
and "data" stream. They were both five level (bit) devices.
If you have problems locating the Brains series, reprints are available
from the Charles Babbage Institute (CBI) at
http://www.cbi.umn.edu.
I don't think they have their document index online - it's been
a while since I looked - but a question or two to their web admin
person found the answers I wanted and got me sufficient info to
order the reprints. It's a worthy organization and they deserve
to be supported through purchases of reprints and their other literature.
My efforts to locate a pair of readers is causing me to look at
other (more current) technologies such as possibly a solid state
memory. In order to make it changeable in "real time" I'm considering
a plug board (using a diode array as you surmised.) Still "retro"
enough to look reasonable?
In Berkeley's design, he included the specific info for obtaining
the readers from the manufacturer (Western Union, if I recall) but
they have long since stopped making such anachronisms. And my
diligent scouring of electronic flea markets, ham fairs, and the
like do not turn up much.
Gary
At 10:20 PM 10/3/98 -0700, you wrote:
>HI Gary and all,
>At 10:27 AM 10/3/98 -0700, you wrote:
>
>>To start things, I'd like to offer that I'm in the process of recreating
>>a copy of Edmund Berkeley's "Simon" computer designed and built by him
>>in the 50's as a demonstration "show and tell" of how a "real" computer
>>works. It's a collection of 100+ relays, two paper tape readers and
>>some blinkey lights. Version 1 was a "two bit" computer with the
>>ability to scale to 4 bits, while version 2 scaling to multiple precision
>>using a real CARRY! It's a small machine - "almost" a "laptop". Right
>>now I'm collecting parts - specifically looking for the two paper tape
>>readers (solenoid operated - not motor driven - so if anyone out there
>>has one or two of these...)
>>
>>For a reference to Simon, see the thirteen part series in Radio Electronics
>>magazine (US publication) from October 1950 through October 1951.
>>"Constructing Electronic Brains" by Edmund C. Berkeley and Robert A. Jensen.
>>There was also a cover article in Scientific American around that time -
>>sorry I don't have the issue handy with an overview of the project.
>>
>
>This sounds interesting. I will try to find the Radio Electronics articles
>you mentioned. Can you describe the paper tape, was it 5 bits? Maybe
>something else
>could be used to simulate it, maybe a mechanical drum or a diode matrix =
>rom if the number of bits isn't too large.
>
>My first "computer" project was the game of "life" using TTL logic, for
>example a 7490 decade counter to count the cell's neighbors as other
>counters moved through the 8 neighbor's x, y addresses.
>
>-Dave
>
Received on Sun Oct 04 1998 - 01:22:32 BST