Four basic periods, each characterized by a principal technology used to solve the input, processing, output and communication problems of the time:
Premechanical,
Mechanical,
Electromechanical, and
Electronic
1. Writing and Alphabets. The first humans communicated
only through speaking and picture drawings. In 3000 B.C., the Sumerians
in Mesopotamia (what is today southern Iraq) devised a writing system. The
system, called "cuniform" used signs corresponding to spoken sounds, instead
of pictures, to express words. From this first information system —
writing — came civilization as we know it today. The Phoenicians around
2000 B.C. further simplified writing by creating symbols that expressed single
syllables and consonants (the first true alphabet). The Greeks later adopted
the Phoenician alphabet and added vowels; the Romans gave the letters Latin
names to create the alphabet we use today.
2. Paper and Pens. For the Sumerians, input technology
consisted of a penlike device called a stylus that could scratch marks in
wet clay. About 2600 B.C., the Egyptians discovered that they could write
on the papyrus plant, using hollow reeds or rushes to hold the first "ink"
- pulverized carbon or ash mixed with lamp oil and gelatin from boiled donkey
skin. Other societies wrote on bark, leaves, or leather. The Chinese developed
techniques for making paper from rags, on which modern-day papermaking is
based, around 100 A.D.
3. Books and Libraries: Permanent Storage Devices. Religious
leaders in Mesopotamia kept the earliest "books"" a collection of rectangular
clay tablets, inscribed with cuneiform and packaged in labeled containers
— in their personal "libraries." The Egyptians kept scrolls - sheets
of papyrus wrapped around a shaft of wood. Around 600 B.C., the Greeks began
to fold sheets of papyrus vertically into leaves and bind them together.
The dictionary and encyclopedia made their appearance about the same time.
The Greeks are also credited with developing the first truly public libraries
around 500 B.C.
4. The First Numbering Systems. The Egyptians struggled
with a system that depicted the numbers 1-9 as vertical lines, the number
10 as a U or circle, the number 100 as a coiled rope, and the number 1,000
as a lotus blossom. The first numbering systems similar to those in use today
were invented between 100 and 200 A.D. by Hindus in India who created a
nine-digit numbering system. Around 875 A.D., the concept of zero was developed.
It was through the Arab traders that today's numbering system — 9 digits
plus a 0 — made its way to Europe sometime in the 12th century.
5. The First Calculators. The existence of a counting
tool called the abacus, one of the very first information processors, permitted
people to "store" numbers temporarily and to perform calculations using beads
strung on wires. It continued to be an important tool throughout the Middle
Ages.
1. The First Information Explosion. Johann Gutenberg in Mainz,
Germany, invented the movable metal-type printing process in 1450 and sped
up the process of composing pages from weeks to a few minutes. The printing
press made written information much more accessible to the general public
by reducing the time and cost that it took to reproduce written material.
The development of book indexes (alphabetically sorted lists of topics and
names) and the widespread use of page numbers also made information retrieval
a much easier task. These new techniques of organizing information would
become valuable later in the development of files and databases.
2. Math by Machine. The first general purpose "computers"
were actually people who held the job title "computer: one who works with
numbers." Difficulties in human errors were slowing scientists and mathematicians
in their pursuit of greater knowledge.
3. Slide Rules, the Pascaline and Leibniz's
Machine.
a. Slide Rule. In the early 1600s, William Oughtred,
an English clergyman, invented the slide rule, a device that allowed the
user to multiply and divide by sliding two pieces of precisely machines and
scribed wood against each other. The slide rule is an early example of an
analog computer — an instrument that measures instead of counts.
b. Pascaline. Blaise Pascal, later to become a famous
French mathematician, built one of the first mechanical computing machines
as a teenage, around 1642. It was called a Pascaline, and it used a series
of wheels and cogs to add and subtract numbers.
c. Leibniz's Machine. Gottfried von Leibniz, an important
German mathematician and philosopher (he independently invented calculus
at the same time as Newton) was able to improve on Pascal's machine in the
1670s by adding additional components that made multiplication and division
easier.
4. Babbage's Engines
a. The Difference Engine. An eccentric English mathematician
named Charles Babbage, frustrated by mistakes, set his mind to creating a
machine that could both calculate numbers and print the results. In the 1820s,
he was able to produce a working model of his first attempt, which he called
the Difference Engine (the name was based on a method of solving mathematical
equations called the "method of differences"). Made of toothed wheels and
shafts turned by a hand crank, the machine could do computations and create
charts showing the squares and cubes of numbers. He had plans for a
more complex Difference Engine but was never able to actually build it because
of difficulties in obtaining funds, but he did create and leave behind detailed
plans.
b. The Analytical Engine. Designed during the 1830s by
Babbage, the Analytical Engine had parts remarkably similar to modern-day
computers. For instance, the Analytical Engine was to have a part called
the "store," which would hold the numbers that had been inputted and the
quantities that resulted after they had been manipulated. It was also to
have a part called the "mill" - an area in which the numbers were actually
manipulated. Babbage also planned to use punch cards to direct the operations
performed by the machine — an idea he picked up from seeing the results
that a French weaver named Joseph Jacquard had achieved using punched cards
to automatically control the patterns that would be woven into cloth by a
loom.
c. Augusta Ada Byron. She helped Babbage design the
instructions that would be given to the machine on punch cards (for which
she has been called the "first programmer") and to describe, analyze, and
publicize his ideas. Babbage eventually was forced to abandon his hopes of
building the Analytical Engine, once again because of a failure to find
funding.
The discovery of ways to harness electricity was the key advance made during
this period. Knowledge and information could now be converted into electrical
impulses.
1. The Beginnings of Telecommunication. Technologies
that form the basis for modern-day telecommunication systems include:
a. Voltaic Battery. The discovery of a reliable method
of creating and storing electricity (with a voltaic battery) at the end of
the 18th century made possible a whole new method of communicating
information.
b. Telegraph. The telegraph, the first major invention
to use electricity for communication purposes, made it possible to transmit
information over great distances with great speed.
c. Morse Code. The usefulness of the telegraph was further enhanced
by the development of Morse Code in 1835 by Samuel Morse, an American from
Poughkeepsie, New York. Morse devised a system that broke down information
(in this case, the alphabet) into bits (dots and dashes) that could then
be transformed into electrical impulses and transmitted over a wire (just
as today's digital technologies break down information into zeros and
ones).
d. Telephone and Radio. Alexander Graham Bell invented
the telephone in 1876. This was followed by the discovery that electrical
waves travel through space and can produce an effect far from the point at
which they originated. These two events led to the invention of the radio
by Marconi in 1894.
2. Electromechanical Computing
a. Herman Hollerith and IBM. By 1890, Herman Hollerith, a young man with a degree in mining engineering who worked in the Census Office in Washington, D.C., had perfected a machine that could automatically sort census cards into a number of categories using electrical sensing devices to "read" the punched holes in each card and thus count the millions of census cards and categorize the population into relevant groups. The company that he founded to manufacture and sell it eventually developed into the International Business Machines Corporation (IBM).
b. Mark 1. Howard Aiken, a Ph.D. student at Harvard
University, decided to try to combine Hollerith's punched card technology
with Babbage's dreams of a general-purpose, "programmable" computing machine.
With funding from IBM, he built a machine known as the Mark I, which used
paper tape to supply instructions(programs) to the machine tor manipulating
data (input on paper punch cards), counters to store numbers, and
electromechanical relays to help register results.
1. First Tries. In the early 1940s, scientists around
the world began to realize that electronic vacuum tubes, like the type used
to create early radios, could be used to replace electromechanical parts.
2. Eckert and Mauchly.
a. The First High-Speed, General-Purpose Computer Using Vacuum Tubes, the ENIAC. John Mauchly, a physicist, and J. Prosper Eckert, an electrical engineer, at the Moore School of Electrical Engineering at the University of Pennsylvania, funded by the U.S. Army, developed the Electronic Numerical Integrator and Computer (ENIAC) in 1946. It could add, subtract, multiply and divide in milliseconds and calculate the trajectory of an artillery round in about 20 seconds.
b. The First Stored-Program Computer. A problem with the ENIAC was that the machine had no means of storing program instructions in its memory - to change the instructions, the machine would literally have to be rewired. Mauchly and Eckert began to design the EDVAC - the Electronic Discreet Variable Computer -to address this problem. John von Neumann joined the team as a consultant and produced an influential report in June 1945 synthesizing and expanding on Eckert and Mauchly's ideas, which resulted in von Neumann being credited as the originator of the stored program concept. Maurice Wilkes, a British scientist at Cambridge University, completed the EDSAC (Electronic Delay Storage Automatic Calculator) two years before EDVAC was finished, thereby taking the claim of the first stored-program computer.
c. The First General-Purpose Computer for Commercial Use. Eckert and Mauchly began the development of a computer called UNIVAC (Universal Automatic Computer), which they hoped would be the world's first general-purpose computer for commercial use, but they ran out of money and sold their company to Remington Rand. A machine called LEO (Lyons Electronic Office) went into action a few months before UNIVAC and became the world's first commercial computer.
3. The Four Generations of Digital Computing. Information technology has traditionally been broken down into four or five distinct stages or computer generations, each marked by the technology used to create the main logic element (the electronic component used to store and process information) used in computers during the period.
a. The First Generation (1951-1958). The first generation of
computers used vacuum tubes as their main logic elements; punched cards to
input and externally store data; and rotating magnetic drums for internal
storage of data in programs written in machine language (instructions written
as a string of 0s and 1s) or assembly language (a language that allowed the
programmer to write instructions in a kind of shorthand that would then be
"translated" by another program called a compiler into machine language).
b. The Second Generation (1959-1963). AT&T's Bell
Laboratories, in the 1940s, discovered that a class of crystalline mineral
materials called semiconductors could be used in the design of a device called
a transistor to replace vacuum tubes. Magnetic cores (very small
donut-shaped magnets that could be polarized in one of two directions to
represent data) strung on wire within the computer became the primary internal
storage technology. Magnetic tape and disks began to replace punched cards
as external storage devices. High-level programming languages (program
instructions that could be written with simple words and mathematical
expressions), like FORTRAN and COBOL, made computers more accessible to
scientists and businesses.
c. The Third Generation (1964-1979). Individual transistors were replaced by integrated circuits — thousands of tiny transistors etched on a small silicon chip. Magnetic core memories began to give way to a new form, metal oxide semiconductor memory (MOS), which, like integrated circuits, used silicon-backed chips. Increased memory capacity and processing power made possible the development of operating systems — special programs that help the various elements of the computer to work together to process information. Programming languages like BASIC were developed, making programming easier to do.
d. The Fourth Generation (1979- Present). The fourth generation
of computers used large-scale and very large-scale integrated circuits (LSIs
and VLSICs), containing hundreds of thousands to over a million transistors
on a single, tiny chip, and microprocessors that contained memory, logic,
and control circuits (an entire CPU) on a single chip. Microprocessors and
VLSICs helped fuel a continuing trend toward microminiaturization where
semiconductor memories increased memory size and speed at every decreasing
prices. Personal computers, like the Apple and IBM PC, were introduced and
quickly became popular for both business and personal use. Fourth generation
language software products such as Access, Lotus 1-2-3, Word for Windows,
and many others allowed persons without any technical background to use a
computer.
Kenneth C. Laudon, Carol Guercio Traver, Jane P. Laudon, Information Technology and Systems.