Many people tend to dismiss the need to learn about our technological heritage. But a subject’s history gives us insight into why things are the way they are today and sharpens our ability to predict future events.
Electronic computers as we know them were invented about 50 years ago. But the history of computers actually goes back much further than that.
Since the beginning of civilization, merchants and government officials have used computing devices to help them with calculations and recordkeeping. The abacus, invented thousands of years ago, is an example of such a device.
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Pascal and Leibniz:
Blaise Pascal, the French mathematician, is credited with inventing the first mechanical calculating machine around 1642. Pascal got the inspiration for his invention at age 19, after spending many hours poring over columns of figures and painstakingly adding them up.
Pascal realized that this tedious chore could be done faster and more accurately with a machine. After much effort, he built a mechanical device that was powered by levers and gears.
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This machine was named the pascaline after its inventor. The pascaline could add and subtract automatically. But it never caught on. Clerks and bookkeepers, fearing for their jobs, refused to use it.
Later in the 1600s, Gottfried Von Leibniz, the German philosopher and mathematician, went one step beyond Pascal and devised a machine that could multiply and divide as well as add and subtract. Like Pascal’s, this device was run by levers and gears.
Jacquard ‘s Loom:
One important event in the development of the computer might seem unrelated at first glance. In the early 1800s, as weaver named Joseph Jacquard invented a look that produced patterned cloth automatically.
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The remarkable thing about this loom was that it used punched cardboard cards to control the pattern in the cloth. The holes in the cards determined which rods in the loom were engaged at any given time.
Jacquard’s loom introduced two concepts that proved important to the future development of the computer. The first concept was that information could be coded on punched cards. Punched cards, as we’ll see, were to become the main input/output medium for the first “modern” computers.
The second concept ; was that the information stored in the cards could serve as a series of instructions- in effect, a program- when the cards were activated.
Babbage and His Engines :
One of the most noteworthy figures in the history of computers was the nineteenth-century English mathematician Charles Babbage. About 150 years ago, he designed a machine with an amazing similarity to the first modern computers.
Babbage first became interested in mechanical computing devices while studying mathematical tables. These tables contained many errors because they had been hand-set into print.
Babbage realized that a machine that could automatically calculate the numbers and print the results would produce much more reliable tables.
Babbage was able to get funds from the British government to build such a machine, which he called the difference engine. He succeeded in building a small prototype. His attempts to build a larger version failed, however, because the technology for creating the parts he needed did not yet exist.
While working on the difference engine, Babbage conceived another, much more powerful machine, which he called the analytical engine. Like the difference engine, it would consist of gears and shafts run by a steam engine.
It is this machine that is so similar in concept to the modern computer. It was to be a general-purpose machine, capable of many kinds of computing work. It would be directed by instructions on punched cards, contain a memory for storing instructions and the intermediate results of calculations, and automatically print results.
Babbage became obsessed with the analytical engine and devoted all of his energy and resources to creating it. But he was never able to complete a working model, and he was never able to complete a working model, and he died without knowing how his vision would shape the future.
Much of what we know about Charles Babbage’s analytical engine comes not from Babbage himself but from the work of his close friend and associate Ada Augusta, Countess of Lovelace, the daughter of the poet Byron.
She has been called “the first programmer” because of her work on the kinds of instructions that would have been fed into the analytical engine to make it work.
Hollerith, the Census, and Punched Cards :
Another milestone on the way to the modern computer was passed during the tabulation of the 1890 U.S. census. Until 1890, census figures had been tabulated manually.
The 1880 census took seven years to complete, and officials worried that if something weren’t done, the results of the 1890 census would not be completed before it was time to begin the 1900 census.
The government commissioned a man named Herman Hollerith to build a machine to aid in the tabulation of the 1890 census. The machine Hollerith built used punched cards and was powered by electricity. With its help, the results of the census were finished in three years.
Hollerith did not rest on his laurels, however. He founded the Tabulating Machine Company to develop punched-card equipment to sell to business and government.
Hollerith’s company merged with several others in 1911 to become the Computer-Tabulating-Recording Company. In 1924, this company changed its name to International Business Machines (IBM) Corporation.
IBM rapidly became the leader in the manufacture of punched-card equipment and had an 80 percent market share by the midl930s. By this time, the mechanical machines of the nineteenth century had been replaced by electromechanical devices such as the one Hollerith pioneered.
Simply put, electromechanical machines are mechanical machines driven by electricity. But while these devices were a vast improvement over their handcranked ancestors, they had some serious drawbacks.
For example, the moving parts were slow to align themselves, which limited their speed. Also, the repeated movement of those parts caused wear, making the machines failure prone.
Aiken, IBM, and the Mark I :
The age of electromechanical computing devices reached its zenith in the early 1940s with the work of Howard Aiken of Harvard University. Aiken had long been interested in developing ways to use these machines for scientific-calculations.
IBM and other manufacturers had designed machines with business users in mind, but during the late 1920s and early 1930s, many scientists began to use them for their work as well.
Aiken had the important insight that the technology of these machines could be adapted to create a general-purpose computer- one that could be programmed to do a variety of computing tasks.
With the support of a $500,000 grant from IBM and the help of four of IBM’s top engineers, Aiken started work on his machine in 1939. Its official name was the “Automatic Sequence Controlled Calculator,” but it came to be called simply the Mark I.
It was completed in 1944 and was gargantuan. It contained 500 miles of wire and 3 million electrical connections. It could do a multiplication in about 6 seconds and a division in about 12 seconds.
The ABC :
While Aiken and IBM were still at work on the Mark I, other were exploring the use of a new technology in computer design- electronics- that would make the Mark I obsolete almost as soon as it was turned on.
Computers with electronic components unlike electromechanical machines, have no moving parts. In electronic machines, the main elements change from one state to another depending on, for example, the presence or absence of current flowing through them.
Because they have no moving parts, electronic machines are much faster and more reliable than electromechanical devices.
The first person to design and build an electronic computing machine was John Atanasoff at Iowa State University. In the late 1930s, Atanasoff needed a machine that could help his graduate students with the tedious job of solving simultaneous linear equations.
None of the machines available at the time met his needs, so he began designing his own. In early 1939, Atanasoff received a $650 grant from Iowa State University.
This sum was enough to buy the part-time services of a graduate student, Clifford Berry, and some materials. Atanasoff and Berry built a machine that they called the ABC, for Atanasoff-Berry Computer.
The main electronic components in the ABC were 300 vacuum tubes. The machine could solve a set of 29 simultaneous equations with 29 variables.
ENIAC :
World War II created a sudden demand for computing power. The U.S. Army, for example, desperately needed accurate tables that would tell gunners how to aim their weapons. These tables required vast numbers of arduous calculations.
As a result, when J Presper Eckert, an electrical engineer, and John Mauchly, a physicist, presented a proposal to the army for an electronic computer that could do these calculations in seconds, they received enthusiastic backing.
Eckert and Mauchly’s computer, called ENIAC (Electronic Numerical Integrator and Calculator), was unveiled in 1946. It was the world’s first large scale, general-purpose electronic computer.
The ENIAC was enormous compared with today’s computers. It was 100 feet long, 10 feet high, and 3 feet deep. It contained 18,000 vacuum tubes and consumed 140 kilowatts of electricity when in operation.
Von Neumann and the Stored-Program Concept :
A major problem with ENIAC was that every time its operators wanted to do a new series of computations, they had to rewire it and reset switches, a process that often took several hours.
John Von Neumann, a mathematician, conceived a way around this shortcoming. He visualized a computer in which processing instructions could be fed in together with the data to be processed.
Both the program and the data could be stored in the computer’s memory. In such a stored-program computer, operators would feed in a new set of instructions when they wanted the computer, operators would feed in a new set of instructions when they wanted the computer to execute a new program; thus, they would not have to rewire the machine. With this stored-program concept, the idea of software was born.
The first stored-program computer, called EDSAC (Electronic Delay Storage Automatic Calculator), was completed in England in 1949. Von Neumann’s machine, ED VAC (Electronic Discrete Variable Automatic Computer), was started in 1946 and completed in the United States in 1950.
With these devices, the stage was set for the computer revolution and the explosive growth of the commercial computer industry.