Chapter 23: Machines that
think? Electronic Computers
Abby Heineman
Catherine Yeager
General Information
Electronic computers were not around until
the mid twentieth century.
► In the early days, computers were large,
slow, and clumsy.
► Its nickname was the dinosaur.
The Story starts about 5,000 years
► With
the Oriental Abacus, a calculating
device of beads and rods.
► Still in use today, in some countries.
► However, its more appropriate to trace
computers, modern computers, back to the
17th century in Europe.
► Scottish
Scientist, John Napier, implemented
a new system of logarithms and a set of
movable sticks.
► These sticks were numbered in a way that
by sliding them in relation to each other,
multiplication was done automatically.
► These sticks were often made of Ivory.
► These sticks became known as Napier’s
Napier's Bones
Early seventeenth century
► Hindu-Arabic
replaced Roman Numerals as
the system of choice for writing numerals in
► Also, this system made it easier for writing
and doing algorithms for doing elementary
arithmetic, which was fairly well developed.
1642 – 1652
► Blaise
Pascal, famous French mathematician,
designed and completed a machine for adding and
► This was called the Pascaline and it is similar to a
cars odometer.
► Used the base ten principle of dials, numbered
zero to nine. It was geared so one full revolution
on one dial would automatically move the next dial
to the next number.
► Numbers, added or subtracted, were dialed in and
the machine did the rest.
The Pascaline
Major difficulty in making mechanical
► Gears,
pivots, or precision devices had to be
individually made by hand.
► Machines were not able to be produced in
large quantities and each one was made
one by one.
► Therefore, the success of the machine was
held “hostage” in the metalworker, not the
Gottfried Leibniz
► One
inventor of Calculus that devised an
improvement on the Pascaline.
► The improvement was multiplication (by repeated
adding) and division (by repeated subtracting).
► Leibniz’s machine was called the Stepped
Reckoner, that represented a major theoretical
advancement over the Pascaline.
► This was because its computations were done in
binary (base 2) arithmetic (AKA-modern computer
► Craftsmanship of 1694, not yet up to making
reliable quantities, so its success was delayed 150
Stepped Reckoner
Early 19th century
► Charles
Babbage, a Cambridge math professor,
began work on a machine for generating accurate
logarithmic and astrology tables.
► This was very important for navigation.
► In 1822, British government took interest in his
► He created the Difference Engine, which created
tables with six place accuracy.
► After many set backs, this project was set aside.
Charles de Colmar of France improved a version of the
Stepped Reckoner called the Arithmometer, which won a
gold metal at the 1862 international exhibit in London.
► Due to mass production techniques from the industrial
revolution, it was manufactured and sold in quantity well
into the 20th century.
► Promoters claimed that the Arithmometer could:
1. Multiply 2 eight digit numbers in 18 seconds.
2. Divide a sixteen digit number by eight digits in 24
3. Find the square root of a sixteen digit number in
one minute.
► It’s slow by today’s standards, but fast compared to hand
calculations, at that time.
Mid 1800’s
► George
Boole, professor of math at Queens
College in Ireland, published two works in machine
1. The Mathematical Analysis of Logic (1847)
2. The Laws of Thought ( 1854)
► Boole explained logic processes could be
expressed by ones and zeros, now called Boolean
It became the theoretical key to all the circuitry of
today’s computers.
► Herman
Hollerith, who was a Census
Employee, created a machine that used
electricity to sort and tabulate data that
had been recorded on punched cards.
► Reduced the sorting time from eight years
to two and a half years.
► Hollerith also founded the Tabulating
Machine Company, which eventually became
Max Newman worked at the British code-breaking center
and devised a way to break German complex code.
► However, the process was far to slow to be practical.
► His concept was then presented to Thomas Flowers –
electronic engineer who worked at the British Post Office.
► In less than one year (March 1943 – January 1944), he
built a machine that used 1500 vacuum tubes to run the
decoding process.
► Machine was dubbed the Colosses, which could decode
German messages in hours instead of weeks or months.
► The design made it twice as fast as some modern Pentium
PC’s doing the same task.
► 10 machines were then built to decode messages; these
machines are thought to have shortened WWII by months
and saved thousands of lives.
► The
first American, general purpose computer was
► It was called the Mark I and was built by Howard
Aiken and IBM engineers at Harvard.
► It used mechanical electromagnetic relays and got
instructions from paper punch tape.
► Mark I was more than 50 feet long; it contained
800,000 parts and 500 miles of wire.
Mark I
ENIAC (Electronic Numerical Integrator and Calculator) was
built by J. Presper Eckert and John Mauchly at the
University of Pennsylvania.
ENIAC intended to help war efforts by calculating naval
artillery firing charts.
Weighing in at 30 tons, it contained:
 42 panels that measured 9 by 2 by 1 foot
 18,000 vacuum tubes
 1500 electrical relays
Its use of vacuum tubes, instead of mechanical relays, was
a major improvement compared to the Mark I (about 500
times faster).
► However, like light bulbs, vacuum tubes burn out with use.
► Programming was done manually by rearranging external
wiring and by flipping switches.
► ENIAC had no data storage capacity.
Vacuum tube technology, like in the ENIAC, was costly in
dependability, cost, and space.
However, this changed when Bell Labs invented the
transistor in the mid-1950s.
Computers used this “second generation” technology and
became smaller, faster, more powerful, and economical.
The third generation introduced integrated circuitry in the
Also, personal computers became more affordable and
have decreased in size from minis all the way to desktops,
laptops, and palmtops.
Brief History of Calculators
The discovery of calculators is given to the French
Mathematician Blaise Pascal; this machine was called the
Arithmetic Machine.
German mathematician, Wilhelm Schickard, wrote a letter
to Johannes Kepler; he wrote about a machine that
“immediately computes the given numbers automatically
(adds, subtracts, multiplies and divides).” No working
copies of his machine were ever found, but working
models have been made from his notes.
Heinz Nixdorf, in 1953, built the first electronic calculator
that resembles today’s models; it performed basic
arithmetic calculations.
After this time, our current calculator competitors
emerged at various times (Texas Instruments, Casio, and
Hewlett Packard).
Technology was developed into today’s calculators by the
rivalry between these three companies.
Come on down, you’re the next
Which early computer is this?
Name this one too…
And last, but not least…
► 1630--John
Napier, implemented a new system of
logarithms and a set of movable sticks.
► 1642 – 1652-- Blaise Pascal designed the
► 1694 – Leibniz’s machine, The Stepped
► 1822 – Babbage created the Difference
► 1862 – de Colmar created the Arithmometer
► Mid-1800s – Boole/Boolean Algebra
Timeline cont’d
► 1880
– Hollerith founded the Machine
Tabulating Co.
► 1937– Max Newman created the Colosses
► 1944 – Aiken created Mark I
► 1946 – ENIAC created by Eckert and
A History of Computers. 15 Nov. 2005
A History of Computers Part 1. 15 Nov. 2005.
Aspray, William ed. Computing Before Computers. Iowa
State University Press. Ames IA. 1990.
Goldstein, Herman. The Computer from Pascal to von
Neumann. Princeton University
Press. Princeton, NJ.
Hoyle, Michelle A. The History of Computing Science. 15
Nov. 2005

Chapter 23: Machines that think? Electronic Computers