[GreenKeys] First Electronic Computer

[Douglas W. Jones]

On Thursday, February 13, 2003, at 08:34 AM, WA5CAB@cs.com wrote:

> Group,
>
> This may be a little off topic but the I/O devices were almost 
> certainly TTY
> machines.  My old boss asked me recently what was the generally accepted
> "first electronic computer" and who is credited with building or 
> designing
> it.  Anyone know?

It's not easy to pin down

For example, the ENIAC was built as a programmable electronc calculator;
as originally planned, it was programmed by great big patch panels, with
the wiring on the patch panel used to control the sequence of the 
computation.
When used in this way, it isn't clear that it would qualify as a computer
in the modern sense of the word.

(From photos I've seen, the patch panels were mounted on full-height
open-frame relay racks on wheels, so you could program a computation
and then wheel it into the machine room to plug in your program and run
it.)

The honor is further complicated by the incremental startup of many of
the machines that were planned as programmable electronic computers.
I've read the early papers of the ILLIAC/ORDVAC development group at
Illinois (sadly, many of the archived papers are ditto copies on which
the blue ink has faded to near transparency).  From those, you can see
that long before the date of official "commissioning" parts of the
computers were far enough along in development that a teletype could be
connected and memory diagnostics run (the oldest printout I found
was a dump from such a venture).  Unfortunately, I wasn't able to find
out if they'd built a custom sequencer to run that diagnostic, or if it
was run by a stored program.

Incidentlally, ILLIAC and ORDVAC were twins, they built two of each
part, and whichever parts could be combined into a working machine
first were declared to be ORDVAC while the remaining parts were
declared to be ILLIAC.

As it became clear that stored-program computation was the way to go,
one of the people in the ENIAC project wired up a patch panel that made
ENIAC into a stored program machine (that patch panel could be described
as a microprogram, in todays terms).  At that point, ENIAC qualified as
a general purpose electronic computer in the modern sense, but that's
not the widely remembered date for ENIAC.

In sum, it's a muddy question.

As to I/O devices, the very first generation machines frequently had
no on-line typewriter device.  Just a paper-tape reader and punch,
with all conversion to print done off-line by a Teletype or Flexowriter.

				Doug Jones
				jones@cs.uiowa.edu