BINAC computer

The invention: The world’s first electronic general-purpose digital
computer.
The people behind the invention:
John Presper Eckert (1919-1995), an American electrical engineer
John W. Mauchly (1907-1980), an American physicist
John von Neumann (1903-1957), a Hungarian American
mathematician
Alan Mathison Turing (1912-1954), an English mathematician
Computer Evolution
In the 1820’s, there was a need for error-free mathematical and
astronomical tables for use in navigation, unreliable versions of
which were being produced by human “computers.” The problem
moved English mathematician and inventor Charles Babbage to design
and partially construct some of the earliest prototypes of modern
computers, with substantial but inadequate funding from the
British government. In the 1880’s, the search by the U.S. Bureau of
the Census for a more efficient method of compiling the 1890 census
led American inventor Herman Hollerith to devise a punched-card
calculator, a machine that reduced by several years the time required
to process the data.
The emergence of modern electronic computers began during
World War II (1939-1945), when there was an urgent need in the
American military for reliable and quickly produced mathematical
tables that could be used to aim various types of artillery. The calculation
of very complex tables had progressed somewhat since
Babbage’s day, and the human computers were being assisted by
mechanical calculators. Still, the growing demand for increased accuracy
and efficiency was pushing the limits of these machines.
Finally, in 1946, following three years of intense work at the University
of Pennsylvania’s Moore School of Engineering, John Presper
Eckert and John W. Mauchly presented their solution to the problems
in the form of the Electronic Numerical Integrator and Calculator (ENIAC) the world’s first electronic general-purpose digital
computer.
The ENIAC, built under a contract with the Army’s Ballistic Research
Laboratory, became a great success for Eckert and Mauchly,
but even before it was completed, they were setting their sights on
loftier targets. The primary drawback of the ENIAC was the great
difficulty involved in programming it. Whenever the operators
needed to instruct the machine to shift from one type of calculation
to another, they had to reset a vast array of dials and switches, unplug
and replug numerous cables, and make various other adjustments
to the multiple pieces of hardware involved. Such a mode of
operation was deemed acceptable for the ENIAC because, in computing
firing tables, it would need reprogramming only occasionally.
Yet if instructions could be stored in a machine’s memory, along
with the data, such a machine would be able to handle a wide range
of calculations with ease and efficiency.
The Turing Concept
The idea of a stored-program computer had first appeared in a
paper published by English mathematician Alan Mathison Turing
in 1937. In this paper, Turing described a hypothetical machine of
quite simple design that could be used to solve a wide range of logical
and mathematical problems. One significant aspect of this imaginary
Turing machine was that the tape that would run through it
would contain both information to be processed and instructions on
how to process it. The tape would thus be a type of memory device,
storing both the data and the program as sets of symbols that the
machine could “read” and understand. Turing never attempted to
construct this machine, and it was not until 1946 that he developed a
design for an electronic stored-program computer, a prototype of
which was built in 1950.
In the meantime, John von Neumann, a Hungarian American
mathematician acquainted with Turing’s ideas, joined Eckert and
Mauchly in 1944 and contributed to the design of ENIAC’s successor,
the Electronic Discrete Variable Automatic Computer (EDVAC), another
project financed by the Army. The EDVAC was the first computer
designed to incorporate the concept of the stored program.In March of 1946, Eckert and Mauchly, frustrated by a controversy
over patent rights for the ENIAC, resigned from the
Moore School. Several months later, they formed the Philadelphiabased
Electronic Control Company on the strength of a contract
from the National Bureau of Standards and the Census Bureau to
build a much grander computer, the Universal Automatic Computer
(UNIVAC). They thus abandoned the EDVAC project, which
was finally completed by the Moore School in 1952, but they incorporated
the main features of the EDVAC into the design of the
UNIVAC.
Building the UNIVAC, however, proved to be much more involved
and expensive than anticipated, and the funds provided by
the original contract were inadequate. Eckert and Mauchly, therefore,
took on several other smaller projects in an effort to raise
funds. On October 9, 1947, they signed a contract with the Northrop
Corporation of Hawthorne, California, to produce a relatively small
computer to be used in the guidance system of a top-secret missile
called the Snark, which Northrop was building for the Air Force.
This computer, the Binary Automatic Computer (BINAC), turned
out to be Eckert and Mauchly’s first commercial sale and the first
stored-program computer completed in the United States.
The BINAC was designed to be at least a preliminary version of a
compact, airborne computer. It had two main processing units.
These contained a total of fourteen hundred vacuum tubes, a drastic
reduction from the eighteen thousand used in the ENIAC. There
were also two memory units, as well as two power supplies, an input
converter unit, and an input console, which used either a typewriter
keyboard or an encoded magnetic tape (the first time such
tape was used for computer input). Because of its dual processing,
memory, and power units, the BINAC was actually two computers,
each of which would continually check its results against those of
the other in an effort to identify errors.
The BINAC became operational in August, 1949. Public demonstrations
of the computer were held in Philadelphia from August 18
through August 20.Impact
The design embodied in the BINAC is the real source of its significance.
It demonstrated successfully the benefits of the dual processor
design for minimizing errors, a feature adopted in many subsequent
computers. It showed the suitability of magnetic tape as an
input-output medium. Its most important new feature was its ability
to store programs in its relatively spacious memory, the principle
that Eckert, Mauchly, and von Neumann had originally designed
into the EDVAC. In this respect, the BINAC was a direct descendant
of the EDVAC.
In addition, the stored-program principle gave electronic computers
new powers, quickness, and automatic control that, as they
have continued to grow, have contributed immensely to the aura of
intelligence often associated with their operation.
The BINAC successfully demonstrated some of these impressive
new powers in August of 1949 to eager observers from a number of
major American corporations. It helped to convince many influential
leaders of the commercial segment of society of the promise of
electronic computers. In doing so, the BINAC helped to ensure the
further evolution of computers.
See also Apple II computer; BINAC computer; Colossus computer;
ENIAC computer; IBM Model 1401 computer; Personal computer;
Supercomputer; UNIVAC computer.