In 1801, Joseph Jacquard from France invented a
powered loom that used wooden punch cards to automatically
weave the detailed patterns including pictures and
text, which was considered as the first “read only
memory”. Certainly, it buried a foundation the computer
punch card that became available many years later.
In 1830, the English mathematician Charles Babbage
proposed a steam-driven calculating machine. That
calculating machine had a size of a room. He named
it “Difference Engine”. It could compute number
tables, like logarithms or navigation tables. He
got a big government funding for the project as
the project had military and commercial significance.
The project was never finished, so Babbage came
up with an even bigger project called the Analytic
Engine. It would have been powered by 6 steam engines
and programmable with help of Jacquard’s punch cards.
Babbage even proposed to use punched paper instead
of wooden cards.
Babbage’ friend Ada Byron, daughter of famous poet
Lord Byron, began “writing programs” for the un-built
machine. The British government refused to get involved
in this project, but Ada became the first computer
programmer. She invented the subroutine and used
“looping”, the re-use of a group of instructions.
The computer programming language, computer Ada,
was named after her.
In 1847, a fellow started working on "symbolic logic".
He felt that we could use mathematical reasoning
to make some decisions. "If Suzy is off work AND
I have $5 OR I can borrow it, we can go to the movies".
Digital computers rely on the functions or operations
of Boolean Algebra like AND, OR, XOR and NOT. George
Boole hoped for the possibilities of human’s logical
actions, just like what computers did a century
The next big thing actually came from America. Tabulating
the US census results in 1880 took seven and a half
years. It was predicted that results for the 1890
census might not be available before the 1900 census
was taken if using the traditional tabulating technique.
So Herman Hollerith invented a process using Jacquard's
punched cards to do the work. A card reader sensed
holes in the cards, a gear driven counter made from
Pascal's idea kept results, and a wall full of dial
indicators displayed the numbers. Hollerith established
a company which eventually became IBM. IBM’s “Hollerith”
cards became ubiquitous.
IBM’s initial mechanical calculators could only
add and subtract. Multiplication was done by repeated
addition. After World War II began, the U.S. military
needed a calculator capable of scientific calculations
in order to make ballistic firing tables for big
naval guns among other things. So Harvard and IBM
built the Mark I computer in 1944 to do the job.
That was a programmable mechanical-electrical digital
computer through punched tape. That computer did
not use binary arithmetic. It used switches, relays,
rotating shafts, and clutches instead. It weighed
5 tons and measured 50 feet long. The Mark I computer
could make addition or subtraction in three-tenths
of a second, multiplication in four seconds, and
division in ten seconds. The computer had nearly
750,000 components although it could store only
Grace Hopper was a programmer on the Mark I. It
was she who developed the first real computer language,
COBOL, abbreviation for Common Business Oriented
Language, in the early 1950s. She is also credited
with having found the first actual computer bug,
a dead moth blocking the paper tape reader, which
made her the first debugger.
Since WWII began, Germany had used a class of electro-mechanical
cipher machines, Enigma, to encode and decode shortwave
radio transmissions. If the allies could decrypt
the code they would know what instructions were
sent to the Wermacht, the location to the Nazi U-Boatsn.
By 1938 the Polish had developed an electro-mechanical
device they called a bomb to speed comparison of
thousands of possible solutions to the code used
in a given message. They gave British intelligence
a copy of an Enigma machine and a bomb in 1939.
At the British code-breaking center Bletchley Park,
Mathematician Alan Turing continued the development
of much larger and more complicated bombs, which
were now called “bombe”.
Another candidate for the grandfather of modern
computers was the Colossus, also built by the British
code breakers at Bletchley Park. Colossus was completed
in 1944. Britain was the world leader in mechanical-electrical-electronic
machines for code breaking. Colossus was a digital,
partially electronic computer but it was certainly
not a general purpose, programmable machine.
The father of the all-electronic digital computer
ought to be ENIAC - Electronic Numerical Integrator
and Calculator built by the University of Pennsylvania
in 1943-45 by John Mauchly and J. Presper Eckert.
Mauchly and Eckert promised the war department that
they could replace all the women employed calculating
the firing tables for the army's artillery guns.
ENIAC was huge, and it worked, although not before
the end of the war. It filled a 20 by 40 foot room,
weighed 30 tons, and used 17,468 vacuum tubes. It
was silent, but hot with 150 kW of power. At the
beginning it required about 8 hours of maintenance
for every 8 hours of use. IBM paper card readers
fed data into the computer that was reprogrammed
by hundreds of patch cords and setting 3000 switches.
ENIAC could only hold 20 numbers at a time, but
with a system clock of 2.8ms and no moving parts
involved it was significantly faster than the Mark
I - a multiplication operation only required 2.8
ms. ENIAC’s first task was computations in the development
of the hydrogen bombs.
ENIAC was difficult to reprogram, requiring changes
to all those patch cords and switches, which could
take days even weeks. Eckert and Mauchly later teamed
up with mathematician John von Neumann to design
EDVAC, which perhaps was the first stored program
computer. After ENIAC and EDVAC came ILLIAC, JOHNNIAC,
and, not surprisingly MANIAC.
Importance of Transistors to Modern Computers
In 1947, IBM commissioned a study and concluded
that six electronic digital computers would be sufficient
to satisfy the computing needs of the entire United
States. Unfortunately that conclusion was short
sighted. There are six computers in an ordinary
car today, all more powerful and much, much faster
than the ENIAC.
Another important event took place in 1947 was that
William Shockley and others at Bell Labs built the
first transistor, which virtually changed everything.
The British call electron tubes “valves” because
a small electrical input voltage controls a much
larger output current. Transistors are electronic
valves too, but are much smaller and more reliable
than tubes, consume much less power. Since the transistors
became available, the development of computers had
moved toward the integrated circuit, which consists
of many transistors on a single piece of silicon.
It was the integrated circuit that made a computer