ENIAC programming Was: release dates of early microcomputer operating systems, incl. Intel ISIS

Dave G4UGM dave.g4ugm at gmail.com
Wed Sep 16 17:18:07 CDT 2015

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Noel
> Chiappa
> Sent: 16 September 2015 22:06
> To: cctalk at classiccmp.org
> Cc: jnc at mercury.lcs.mit.edu
> Subject: Re: ENIAC programming Was: release dates of early microcomputer
> operating systems, incl. Intel ISIS
>     > From: Al Kossow
>     >> the machine had to be configured (via connecting up computing units
>     >> with cables)
>     > In 1947 ENIAC was modifed at BRL to be a stored program computer.
> Well, I did say "in the original ENIAC usage" it had to be configured by
> plugging! I was aware of the later conversion.
>     > http://dl.acm.org/citation.cfm?id=1339839
>     Crispin Rope, "ENIAC as a Stored-Program Computer: A New Look at the
> Old
> 	Records", IEEE Annals of the History of Computing, Vol. 29 No. 4,
> 	October 2007
> Thanks for that pointer. I couldn't get access to that paper (it's behind
> paypal I don't have the ability to pierce - I would be grateful if someone
> send me a copy), but in looking for it online,

I struggled to get it out of the University Library system.

>  I did find the very
> similar:
>     Thomas Haigh, Mark Priestley, Crispin Rope, "Engineering 'The Miracle
> 	the ENIAC'", IEEE Annals of the History of Computing, Vol. 36, No.
> 	April-June 2014
> which includes the same author, and is later, so hopefully more
> It's quite interesting: according to that, the conversion of ENIAC to a
> program' configuration, after a period of about a year of discussion and
> planning, took place starting around March, 1948, and the first problem
> run using it in April, 1948 - and it cites a lot of contemporary documents
> that effect.
> (As the article points out, this contradicts the long-and-widely-held
> impression, from a statement in Goldstine's book - and if anyone knew, it
> should have been him! - that gave the date of that as September, 1948.)
> Anyway, the new, earlier date is of course is very shortly before the Baby
> _its_ first program, in June, 1948. So there is a rather interesting
question as
> to which 'computer' ran first. I'd always gathered it was the Baby, but
> new data may overturn that.

I believe that its generally accepted that is true. 

> It is true that the 'program ENIAC' (to invent a term to differentiate
> stage of the machine from the earliest configurations, which used the
> method) did not store its program in the same read-write memory as data,
> the Baby did, instead storing it in 'EPROM' (switches). However, I don't
> consider that very important; nobody says that a machine running out of
> PROM isn't a computer!

It is notable that in order to solve all problems, a computer must permit
self modifying code.
In the above article Crispin notes that ENIAC was succeeded by the IBM 701
and then omits the fact 
that the 701 used the Williams tubes from the Baby as its main store, so
clearly both machines had a non-significant
influence on early computing. Without Williams and ENIAC there would have
been no IBM701...

> The important thing is that it's a program, with things like subroutine
> from different locations, address modification for data access, etc, and
> 'program ENIAC' apparently had all that (see the list at the bottom of
page 51
> in the article). So it's likely indeed be the 'first computer'.
> 	Noel

What is and isn't a computer is always open to debate. The Manchester SSEM
or Baby is I would say the simplest thing that you could call a computer.
I could explain how to program the Baby to almost any one on this list. It
has seven instructions, so in a 32 bit word, a 5 bit address and a 3 bit op

Crispin Rope concentrates on the power of ENIAC and its usefulness, neither
of which can be argued with, but to me a "computer" without self-modifying
code is a programmable calculator even if it has index registers... 
If you want to rate a computer by the work it did ENIAC was far more useful,
but the SSEM was never intended to be a "Useful" computer. It was a testbed
for the Williams Tube.

... on the other hand whilst both added to our knowledge of computing in the
longer term neither were IMHO especially influential going forward.
Self-Modifying code became the norm, and Williams Tubes were rapidly
superseded by core...

>From what I have seen the UK was slow to move onto Core store, probably
because IBM bought the patents, so whilst the IBM 704 was already using Core
in 1954 the Ferranti Pegasus from 1956 went back to using Nickle Delay Lines
and a Drum for "Main Store" although IMHO the Delay Lines were really main
store, from what I remember all code must be in the delay lines. The LEO
(Lyons Electronic Office) also used Mercury Delay Lines....

Dave Wade

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