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THE EVOLUTION OF THE COMPUTER
Charles Babbage is often referred as the "father of computing" because of his invention of the analytical engine, a prototype of
which was completed far after his death. The Charles Babbage Foundation took his name to honor his intellectual contributions and their relation to modern computers.
Charles Babbage was born in London on December 26, 1792 [N.B., Bromley actually got this wrong; his birth year is regarded as 1791], the son of Benjamin Babbage, a London banker. As a
youth Babbage was his own instructor in algebra, of which he was passionately fond, and was well-read in the continental mathematics of his day. Upon entering Trinity College,
Cambridge, in 1811, he found himself far in advance of his tutors in mathematics. With Herschel, Peacock, and others, Babbage founded the Analytical Society for promoting continental
mathematics and, reforming the mathematics of Newton then taught at the university.
In his twenties Babbage worked as a mathematician, principally in the calculus of functions. He was elected a Fellow of the Royal
Society, in 1816, and played a prominent part in the foundation of the Astronomical Society (later Royal Astronomical Society) in 1820. It was about this time that Babbage first acquired the
interest in calculating machinery that became his consuming passion for the remainder of his life.
Throughout his life Babbage worked in many intellectual fields typical of his day, and made contributions that would have
assured his fame irrespective of the Difference and Analytical Engines. Prominent among his published works are A Comparative View of the Various Institutions for the Assurance of Lives (1826), Table of Logarithms of the Natural Numbers
from 1 to 108, 000 (1827), Reflections on the Decline of Science in England (1830), On the Economy of Machinery and Manufactures (1832), Ninth Bridgewater Treatise (1837), and the
autobiographical Passages from the Life of a Philosopher (1864). Babbage occupied the Lucasian chair of mathematics at Cambridge from 1828 to 1839. He played an important role in the
establishment of the Association for the Advancement of Science and the Statistical Society (later Royal Statistical Society).
Despite his many achievements, the failure to construct his calculating machines, and in particular the failure of the
government to support his work, left Babbage in his declining years a disappointed and embittered man. He died at his home in Dorset Street, London, on October 18, 1871.
Charles Babbage's Analytical Engine
Charles Babbage, a professor of mathematics at Cambridge University in England, is recognized as the father of computers.
He believed that mental as well as physical labor should be aided by machines. He took the first major third Class step in the evolution of the computer. In 1830 he began to design and build
what was to be the first completely automatic, general-purpose, digital computer He named this computer the Analytical Engine because of the way it was to perform mathematical calculations
based on numbers stored in a storage unit within it. The arithmetic and storage units of the machine were to be governed by a control unit that would coordinate and supervise the sequence of
operations. Babbage continued to work on the Analytical Engine until his death in 1871. Because his ideas were far beyond the technical capabilities of that time, he was not able to complete the
engine. Nevertheless, he must be given credit for having the foresight to design and attempt to build a machine that was about 100 years ahead of its time
The Mark I Computer
After Babbage died, no significant progress was made in the development of automatic computation until 1937. In 1937
Professor Howard Aiken of Harvard University began to build an automatic calculating machine. The machine would combine the technical capabilities of that time with the punched card concepts
developed by Hollerith and Powers. In 1944 the project was completed, and a machine known as the Mark I was formally presented to Harvard University. By 1945 the Mark I was
providing computing support to the Bureau of Ships. The Mark I was relatively slow because the speed of its calculations depended on the speed of many electromechanical relays and
other components. Internal processing functions were measured in seconds. Unlike previous calculators, however, Aiken's machine was able to compare quantities and select alternate
paths of computation. In many ways the Mark I was the realization of Babbage's dream. Although slower than modern computers, is are the Mark I is still operational and is on display at Harvard
University.
The Harvard Mark I computer could carry out five operations, addition, substraction, multiplication, division and reference
to previous results; moreover, it had special built-in programs, or subroutines, to handle logarithms and trigonometric functions. It stored and counted numbers mechanically using 3000 decimal
storage wheels,  1400 rotary dial switces, and 500 miles of wire
but transmitted and read the data electrically.
It was programmed by punch cards, weighed 5 tons, and could do a multiplication operation in about 6 seconds. Like the earliest mechanical
computers, the data to be used in a Mark computer was stored in a separate part of the machine from the instructions (or program) that would operate on the data. Also,
the instructions were stored in a different format than the data.
The Mark I was originally controlled from pre-punched paper tape without provision for reversal, so that automatic "transfer of
control" instructions could not be programmed. Output was by card punch and electric typewriter. Because of the electromagnetic relays, the machine was classified as a relay
computer. It was fully automatic and could complete long computations without human intervention.
The ENIAC
The first all-electronic digital computer was designed and built in the early l940s at the University of Pennsylvania's Moore School
of Electrical Engineering. The team of John W. Mauchly and J. Presper Eckert, Jr., was responsible for the construction of the computer. They named it the Electronic
Numerical Integrator and Calculator (ENIAC). The ENIAC was completely electronic; it used vacuum
(electron) tubes rather than electromechanical relays. Unlike relays, vacuum tubes do not have to move to perform their functions. This improvement made ENIAC hundreds of times
faster than the Mark I. The ENIAC weighed about 30 tons, took up about 1,500 square feet of floor space, and used 18,000 vacuum tubes. The fastest electromechanical machine of that time could
perform only one multiplication per second. With the use of vacuum tubes, the ENIAC could process 300 multiplication's per second. It could do in one day what would have taken 300 days to do manually.
The EDVAC
In 1945 Mauchly, Eckert, and others went on to build the Electronic  Discrete Variable Automatic Computer (EDVAC). It was smaller than either the Mark I or the
ENIAC and had greater capability. Two design features that distinguished the EDVAC from the ENIAC were the use of binary numbers and the internal storage of
instructions in digital form. Up to this point, primary emphasis was placed on building computers for use on scientific projects. In 1946 Eckert and Mauchly founded their
own corporation to begin building computers for commercial use. The computers were to be business oriented, designed primarily to process business data.
The UNIVAC I
Next Eckert and Mauchly built the "UNIVersal Automatic Computer" (UNIVAC I). It was to be the first computer built with the
assumption that several computers of the same type would be built and sold. Until the development of the UNIVAC I, computers were only one of a kind. The UNIVAC I was the first computer to
use magnetic  tape for input and output. Previously, computers had
used slower input-output, such as punched cards and paper tape. The company of Eckert and Mauchly became a subsidiary of Remington Rand in 1949, and later it became the Sperry Univac Division of
Sperry Rand Corporation. The first UNIVAC I computer was installed at the United States Bureau of Census in 1951. It was used by the Bureau of
Census until 1963., when it was classified obsolete and placed in the Smithsonian Institution. The introduction of the UNIVAC I computer to the government and business communities opened
up a new field and was a major factor behind the growth of the computer industry. Since 1952 tremendous improvements have been made in computers, far too many to mention. However, you
should know how it all began and you should realize how rapidly our technology in the computer industry has advanced.
COMPUTER GENERATIONS
In the computer world, we measure technological advancement by generations. Computer systems are classified as belonging to a
specific "generation." Each generation indicates a significant change in computer design. The UNIVAC I represents the first generation. Currently, we are moving toward the fourth generation.
First Generation (1951-1958)
The computers of the first generation were physically very large machines characterized by the vacuum tube Because they used
vacuum tubes, they were very unreliable, required a lot of power to run, and produced so much heat that strict air conditioning was needed to protect the computer parts. Compared to today's
computers, they had slow input and output devices, were slow in processing, and had small storage capacities. Many of the internal processing functions were measured in thousandths of a
second (millisecond). The software (computer program) used on first generation computers was unsophisticated and machine oriented. This meant that the programmers had to code all
computer instructions and data in actual machine language. They also had to keep track of where instructions and data were stored. Using such a machine language was efficient for the computer but
difficult for the programmer.
Second Generation (1959-1963)
The computers of the second generation were characterized by transistors instead of vacuum tubes. Transistors were smaller,
less expensive, generated almost no heat, and required very little power. Thus second generation computers were much smaller, required less power, and produced a lot less heat. The use of
small, long lasting transistors also increased processing speeds and reliability. Cost performance also improved. The amount of storage capacity was greatly increased with the introduction of
magnetic disk storage and the use of core for main storage. High speed card readers, printers, and magnetic tape units were also introduced. Internal processing speeds increased. Functions were
measured in millionths of a second (microseconds). Like the first generation, a particular computer of the second generation was designed to process either scientific or business oriented
problems but not both. The software was also improved. Symbolic machine languages or assembly languages were used instead of actual machine languages. This allowed the programmer to use
mnemonic operation codes for instruction operations and symbolic names for storage locations or stored variables. Compiler languages were also developed for the second
generation computers. The two most popular were FORmula TRANslator (FORTRAN) and the COmmon Business Oriented L
anguage (COBOL). FORTRAN was developed as a scientific language and COBOL as a business oriented language.
Third Generation (1964-1970)
The computers of this generation (many of which are still in use) are characterized by miniaturized circuits. This reduces the
physical size of computers even more and increases their durability and internal processing speeds. One design employs solid-state logic microcircuits for which conductors, resistors,
diodes, and transistors have been miniaturized and combined on half-inch ceramic squares. Another smaller design uses silicon wafers on which the circuit and its components are etched. The
smaller circuits allow for faster internal processing speeds resulting in faster execution of instructions. Internal processing speeds are measured in billionths of a second (nanoseconds).
The faster computers make it possible to run jobs that were considered impractical or impossible on first or second generation equipment. Because the miniature components are
more reliable, maintenance is reduced. New mass storage, such as the data cell, was introduced during this generation, giving a storage capacity of over 100 million characters. Drum and disk
capacities and speed have been increased, the portable disk pack has been developed, and faster, higher density magnetic tapes are in use. Considerable improvements have been made to
card readers and printers while the overall cost has been greatly reduced. Applications using online processing, real-time processing, time sharing, multiprogramming, multiprocessing,
and teleprocessing have become widely accepted. Manufacturers of third generation computers are producing series of similar and compatible computers. This allows programs written for one
computer model to run on most larger model of the same series. Most third generation systems are designed to handle both scientific and business data processing applications. This is
particularly valuable to DP installations with both kinds of data processing requirements. Improved program and operating software has been designed to provide better control resulting in
faster processing. These enhancements are of significant importance to the computer operator. They simplify system initialization and minimize the need for console intervention by the operator.
Fourth Generation and Beyond (1970 - Present)
The computers of the fourth generation are not as easily distinguished from earlier generations, yet there are some striking
and important differences. The manufacturing of integrated circuits has advanced to the point where thousands of circuits (active components) can be placed on a silicon wafer only a
fraction of an inch in size (the computer on a chip). This has led to what is called large scale integration (LSI) and very large scale
integration (VLSI). As a result of this technology, computers are significantly smaller in physical size and lower in cost. Yet they have retained large memory capacities and are ultra fast. Large
mainframe computers are increasingly complex. Medium sized computers can perform as large third generation computers do. An entirely new breed of computers called microcomputers and
minicomputers are small and inexpensive, and yet they provide a lot of computing power. These micro/mini computers are being manufactured by many different companies and are rapidly
gaining popularity.
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