Existence Precedes Essence - Meaning of the Stored-Program Concept - History of Computing: Learning from the Past - page 169

Existence Precedes Essence - Meaning of the
Stored-Program Concept
Allan Olley
IHPST, University of Toronto
91 Charles St., Toronto, ON, Canada
[e-mail]
Abstract. The emergence of electronic stored-program computers in contain
the 1940s marks a break with past developments in machine calculation. Draw-
ing on the work of various historians, I attempt to define the essence of that
break and therefore of the modern computer. I conclude that the generally used
distinction between computers and precursor machines in terms of the stored-
program concept and von Neumann architecture rests not only on differences in
hardware but also in the programming and use of machines. Next I discuss the
derived definition in terms of machines from the 1940s and 50s to elucidate the
definition's implications for the history of computing.
Keywords: Stored-program, von Neumann architecture, computer history,
computer architecture, history of software, IBM SSEC.
1 Introduction
The July 1939 issue of Astounding Science-Fiction included an article entitled “Tools
for Brains” by one Leo Vernon. This article included a brief history of calculating
machines, including mention of Charles Babbage and short discussion of recent scien-
tific uses of punched card machines at Columbia and differential analyzers at MIT.
He concludes by speculating on future machines sketching what a “dream machine”
for such scientific computation might look like:
“The dream machine may fill an entire building. It will be operated from a
central control room made up entirely of switchboard panels, operated by
trained mathematicians, and an automatic printer giving back the results. A
physicist has spent months getting a problem ready for solution. He has long
tables of numbers, experimental data. These numbers have to be combined
and recombined with still more numbers, producing hundreds of thousands
or millions of numbers...” [1]
Vernon imagined the subsequent calculation occurring in minutes and with the aid of
mathematical tables punched onto paper tape. [1]
Vernon's predictions seem in some aspects prescient and in some aspects com-
pletely wrong. Computing machines soon did become very large and very fast, but
soon Vernon's dreams of a machine operated by a room full of switchboards would