Evening star., 1947-11-12
Stars, Men and Atoms
Thinking Electric Broin
Being Built for Army

thinking EieStIiS 0'o"
Being Built for Army
Hish.Speed Calculator Can Exercise
Some Freedom of Choice
By Thomas r. Henry
An electric brain that thinks" now Is being
built for the Army
such a machine, which can not only carry
out calculations Of extremely complicated
mathematical problems with essentially the
speed Of light but which also can exercise some
degree Of free choice and initiative, Is under
construction at the University Of Pennsyl-
yania for the Ballistic Research Laboratories
at Aberdeen, Md.
This Is the Edvac, combining the virtues OF
two supermechanical oalculators developed
under Army direction during the war TO solve
extremely complicated problems Of baIistics.
performing In a few minutes problems which
would have required days IN the hands OF
expert computers.
Eniao Is Best Known.
Best known Of these, developed ut the Uni
versity of Pennsylvania was the Ensac. Its
nerve cells were vacuum tubes The great
virtue Of this machine was the extreme speed
tions can be performed in an hour. But the
extraordinarily complicated apparatus could
do only what 1t was told" A problem to be
solved must be set up by experts who set
numerous switches and plugging wires. This
requires much time and there Is considerable
risk Of errors. But once the setup Of q problem
Is accomplished and tested against error nu-
merous other problems Of the same kind can
be carried out several hundred times faster
than by hand.
simultaneously with the construction Of the
Er1iac another machine was developed for the
ballistics laboratory by the Bell Telephone Co.
Instead of vacuum tubes this machine uses
relays Of the same kind as are used in tele-
phone exchanges. It was called the Stibitz
machine after its inventor, Dr.. George r.
Stibitz Of the Bell Laboratories staff.
The great advantage Of this machine was its
ability to perform much more complicated
problems and to exercise what might be con-
sidered the rudiments of free choice, one Of
the major differences between thinking" and
mere calculating.
Some of the more frequent, although by no
means the most complicated, choices the ma
chine will perform are listed by Franz L. Alt
of the ballistics laboratory through the Amer
lean Statistical Association.
In pIOOIcL1 SOlNcu Uy SuCCSSSlV0 6ppIUAl~
nation the machine repeats the tterative
process until the difference between two sue
cessive approximations is smaller than q pre-
determined limit. Then 1t discontinues, prints
the answers obtained, and automatically starts
computation on the next problem.
To Operate Unattended
"It Is designed to operate at night without
the presence Of human operator. If during
unattended hours some trouble occurs-this
may be either failure Of some part Of the
machine or an error OF the operator who had
previously set the machine up for q particular
probenl-the machine will wait a short time
to see If the trouble clears up and then will
automatically discontinue all computations on
the present problem and immediately start
work on any other problem that has been pre-
pared for It,"
The great drawback Of the stibstz machine
was that 1t was too slow. It could do much
more complicated computations than the
Eniac, but its rate was less than hundredth
as fast. The two mechanical brains were
based on quite different principles.
Now, Alt reports In the American Statistical
Associations current journal, the two are being
successfully combined for the ballistics lab
oratory at the Moore School Of Electrical Engt-
neering of the University OF Pennsylvania.
The new machine-the "electronic discrete
variable computer"-will operate with vacuum
tubes and will have essentially the speed Of
the Eniac, but at the same time will have more
choice" and be able to work out more compl-
Gated problems than the telephone relay
mechanism.
It will be superior to both IN memory
the ability to store up numbers at one stage Of
a problem for Use at some later stage. This
machine, says Alt, will enable us to solve
problems which hitherto have been inaccessible
to numerical methods"