Generally, a computer is any device that can
perform numerical calculations--even an adding machine, an abacus, or a slide
rule. Currently, however, the term usually refers to an electronic device that
can use a list of instructions, called a program, to perform calculations or to
store, manipulate, and retrieve information.
Today's
computers are marvels of miniaturization. Machines that once weighed 30 tons
and occupied warehouse-size rooms now may weigh as little as three pounds (1.4
kilograms) and can be carried in a suit pocket. The heart of today's computers
are integrated circuits (ICs), sometimes called microchips, or simply chips.
These tiny silicon wafers can contain millions of microscopic electronic
components and are designed for many specific operations: some control an
entire computer (CPU, or central processing unit, chips); some perform millions
of mathematical operations per second (math coprocessors); others can store
more than 16 million characters of information at one time (memory chips).
In 1953
there were only about 100 computers in use in the entire world. Today hundreds
of millions of computers form the core of electronic products, and more than
110 million programmable computers are being used in homes, businesses,
government offices, and universities for almost every conceivable purpose.
Computers come in many sizes and shapes. Special-purpose, or dedicated,
computers are designed to perform specific tasks. Their operations are limited
to the programs built into their microchips. These computers are the basis for
electronic calculators and can be found in thousands of other electronic
products, including digital watches (controlling timing, alarms, and displays),
cameras (monitoring shutter speeds and aperture settings), and automobiles
(controlling fuel injection, heating, and air conditioning and monitoring
hundreds of electronic sensors).
General-purpose computers, such as personal computers and business
computers, are much more versatile because they can accept new sets of
instructions. Each new set of instructions, or program, enables the same
computer to perform a different type of operation. For example, one program
lets the computer act like a word processor, another lets it manage
inventories, and yet another transforms it into a video game.
Although
some general-purpose computers are as small as pocket radios, the smallest
class of fully functional, self-contained computers is the class called
notebook computers. These usually consist of a CPU, data-storage devices called
disk drives, a liquid-crystal display (LCD), and a full-size keyboard--all
housed in a single unit small enough to fit into a briefcase.
Today's
desktop personal computers, or PCs, are many times more powerful than the huge,
million-dollar business computers of the 1960s and 1970s. Most PCs can perform
from 16 to 66 million operations per second, and some can even perform more
than 100 million. These computers are used not only for household management
and personal entertainment, but also for most of the automated tasks required
by small businesses, including word processing, generating mailing lists,
tracking inventory, and calculating accounting information.
Minicomputers are fast computers that have greater data manipulating capabilities
than personal computers and can be used simultaneously by many people. These
machines are primarily used by larger businesses to handle extensive
accounting, billing, and inventory records.
Mainframes are large, extremely fast, multi-user computers that often
contain complex arrays of processors, each designed to perform a specific
function. Because they can handle huge databases, can simultaneously
accommodate scores of users, and can perform complex mathematical operations,
they are the mainstay of industry, research, and university computing
centers.
The
speed and power of supercomputers, the fastest class of computer, are almost
beyond human comprehension, and their capabilities are continually being
improved. The most sophisticated of these machines can perform nearly 32
billion calculations per second, can store a billion characters in memory at
one time, and can do in one hour what a desktop computer would take 40 years to
do. Supercomputers attain these speeds through the use of several advanced
engineering techniques. For example, critical circuitry is supercooled to
nearly absolute zero so that electrons can move at the speed of light, and many
processors are linked in such a way that they can all work on a single problem
simultaneously. Because these computers can cost millions of dollars, they are
used primarily by government agencies and large research centers.
Computer
development is rapidly progressing at both the high and the low ends of the
computing spectrum. On the high end, by linking together networks of several
small computers and programming them to use a language called Linda, scientists
have been able to outperform the supercomputer. This technology is called
parallel processing and helps avoid hours of idle computer time. A goal of this
technology is the creation of a machine that could perform a trillion
calculations per second, a measure known as a teraflop. On the other end of the
spectrum, companies like Apple and Compaq are developing small, handheld personal
digital assistants (PDAs). The Apple Newton, for example, lets people use a pen
to input handwritten information through a touch-sensitive screen and to send
mail and faxes to other computers. Researchers are currently developing
microchips called digital signal processors, or DSPs, to enable these PDAs to
recognize and interpret human speech. This development, which will permit
people in all professions to use a computer quickly and easily, promises to
lead to a revolution in the way humans communicate and transfer
information.
Computers at Work--Applications
Communication.
Computers make all modern communication possible. They operate telephone
switching systems, coordinate satellite launches and operations, help generate
special effects for movies, and control the equipment in all phases of
television and radio broadcasts. Local-area networks (LANs) link the computers
in separate departments of businesses or universities, and larger networks,
such as the Internet, permit modems--telecommunication devices that transmit
data through telephone lines--to link individual computers to other computers
anywhere in the world. Journalists and writers now use word processors to write
books and articles, which they then submit to publishers on magnetic disks or
through telephone lines. The data may then be sent directly to
computer-controlled typesetters, some of which actually design the layout of
printed pages on computer screens.
Science and research. Computers are used by scientists and researchers in many ways to
collect, store, manipulate, and analyze data. Running simulations is one of the
most important applications. Data representing a real-life system is entered
into the computer, and the computer manipulates the data in order to show how
the natural system is likely to behave under a variety of conditions. In this
way scientists can test new theories and designs or can examine a problem that
does not lend itself to direct experimentation. Computer-aided design, or CAD,
programs enable engineers and architects to design three-dimensional models on
a computer screen. Chemists may use computer simulation to design and test
molecular models of new drugs. Some simulation programs can generate models of
weather conditions to help meteorologists make predictions. Flight simulators
are valuable training tools for pilots.
Industry. Computers have
opened a new era in manufacturing and consumer-product development. In the
factory, computer-assisted manufacturing, or CAM, programs help people plan
complex production schedules, keep track of inventories and accounts, run
automated assembly lines, and control robots. Dedicated computers are routinely
used in thousands of products ranging from calculators to airplanes.
Government. Government
agencies are the largest users of mainframes and supercomputers. The United
States Department of Defense uses computers for hundreds of tasks, including
research, breaking codes, interpreting data from spy satellites, and targeting
missiles. The Internal Revenue Service uses computers to keep track of tens of
millions of tax returns. Computers are also essential for taking the census,
maintaining criminal records, and other tasks.
Education. Computers have
proved to be valuable educational tools. Computer-assisted instruction, or CAI,
uses computerized lessons that range from simple drills and practice sessions
to complex interactive tutorials. These programs have become essential teaching
tools in medical schools and military training centers, where the topics are
complex and the cost of human teachers is extremely high. Educational aids,
such as some encyclopedias and other major reference works, are available to
personal-computer users--either on magnetic disks or optical discs or through
various telecommunication networks.
Arts and Entertainment. Video games are one of the most popular applications of personal
computers. The constantly improving graphics and sound capabilities of personal
computers have made them popular tools for artists and musicians. Personal
computers can display millions of colors, can produce images far clearer than
those of a television set, and can connect to various musical instruments and
synthesizers. Painting and drawing programs enable artists to create realistic
images and animated displays much more easily than they could with more
traditional tools. "Morphing" programs allow photographers and
filmmakers to transform photographic images into any size and shape they can
imagine. High-speed supercomputers can insert life-like animated images into
frames of a film so seamlessly that movie-goers cannot distinguish real actors
from computer-generated images. Musicians can use computers to create
multiple-voice compositions and to play back music with hundreds of variations.
Speech processors even give a computer the ability to talk and sing.
Types of Computers
There are two fundamentally different types of
computers--analog and digital. (Hybrid computers combine elements of both
types.) Analog computers solve problems by using continuously changing data
(such as pressure or voltage) rather than by manipulating discrete binary
digits (1s and 0s) as a digital computer does. In current usage, the term
computer usually refers to digital computers. Digital computers are generally
more effective than analog computers for four principal reasons: they are
faster; they are not as susceptible to signal interference; they can convey
data with more precision; and their coded binary data are easier to store and
transfer than are analog signals.
Analog computers. Analog computers work by translating constantly changing physical
conditions (such as temperature, pressure, or voltage) into corresponding
mechanical or electrical quantities. They offer continuous solutions to the
problems on which they are operating. For example, an automobile speedometer is
a mechanical analog computer that measures the rotations per minute of the
drive shaft and translates that measurement into a display of miles per hour.
Electronic analog computers in chemical plants monitor temperatures, pressures,
and flow rates and send corresponding voltages to various control devices,
which, in turn, adjust the chemical processing conditions to their proper
levels.
Digital computers. For all their apparent complexity, digital computers are basically
simple machines. Every operation they perform, from navigating a spacecraft to
playing a game of chess, is based on one key operation--determining whether
certain switches, called gates, are open or closed. The real power of a
computer lies in the speed with which it checks these switches--anywhere from 1
million to 4 billion times, or cycles, per second.
A
computer can recognize only two states in each of its millions of circuit
switches--on or off, or high voltage or low voltage. By assigning binary
numbers to these states--1 for on and 0 for off, for example--and linking many
switches together, a computer can represent any type of data--from numbers to
letters to musical notes. This process is called digitization.
Imagine
that a computer is checking only one switch at a time. If the switch is on, it
symbolizes one operation, letter, or number; if the switch is off it represents
another. When switches are linked together as a unit, the computer can
recognize more data in each cycle. For example, if a computer checks two
switches at once it can recognize any of four pieces of data--one represented
by the combination off-off; one by off-on; one by on-off; and one by on-on. The
more switches a computer checks in each cycle, the more data it can recognize
at one time and the faster it can operate. Below are some common groupings of
switches (each switch is called a binary digit, or bit) and the number of
discrete units of data that they can symbolize:
4 bits
= a nibble (16 pieces of data);
8 bits =
a byte (256 pieces of data);
16 bits
= a word (65,536 pieces of data).
32 bits
= a double word (4,294,967,296 pieces of data).
A byte is the basic unit of data storage because
all characters, numbers, and symbols on a keyboard can be symbolized by using a
combination of only eight 0s and 1s.
Each
combination of ons and offs represents a different instruction, part of an
instruction, or type of data (number, letter, or symbol). For example,
depending on its context in a program, a byte with a pattern of 01000001 may
symbolize the number 65, the capital letter A, or an instruction to the
computer to move data from one place to another.
PARTS OF A DIGITAL COMPUTER SYSTEM
A digital computer is a complex system of four
functionally different elements--a central processing unit, input devices,
memory-storage devices, and output devices--linked by a communication network,
or bus. These physical parts and all their physical components are called
hardware.
Without
a program, a computer is nothing but potential. Programs, also called software,
are detailed sequences of instructions that direct the computer hardware to
perform useful operations.
Hardware
The central processing unit, or CPU, is the heart of a computer. In addition to performing arithmetic
and logic operations on data, it times and controls the rest of the system.
Mainframe CPUs sometimes consist of several linked microchips, each performing
a separate task, but most other computers require only a single microprocessor
as a CPU.
Most CPU
chips and microprocessors have four functional sections:
(1) the
arithmetic/logic unit, which performs arithmetic operations (such as addition
and subtraction) and logic operations (such as testing a value to see if it is
true or false);
(2)
temporary storage locations, called registers, which hold data, instructions,
or the results of calculations;
(3) the
control section, which times and regulates all elements of the computer system
and also translates patterns in the registers into computer activities (such as
instructions to add, move, or compare data); and
(4) the
internal bus, a network of communication lines that links internal CPU elements
and offers several different data paths for input from and output to other
elements of the computer system.
Input devices let
users enter commands, data, or programs for processing by the CPU. Computer
keyboards, which are much like typewriter keyboards, are the most common input
devices. Information typed at the keyboard is translated into a series of
binary numbers that the CPU can manipulate. Another common input device, the
mouse, is a mechanical or optomechanical device with buttons on the top and a
rolling ball in its base. To move the cursor on the display screen, the user
moves the mouse around on a flat surface. The user selects operations,
activates commands, or creates or changes images on the screen by pressing
buttons on the mouse. Other input devices include joysticks and trackballs.
Light pens can be used to draw or to point to items or areas on the display
screen. A sensitized digitizer pad translates images drawn on it with an
electronic stylus or pen into a corresponding image on the display screen.
Touch-sensitive display screens allow users to point to items or areas on the
screen and to activate commands. Optical scanners "read" characters
on a printed page and translate them into binary numbers that the CPU can use.
Voice-recognition circuitry digitizes spoken words and enters them into the computer.
Memory-storage devices. Most digital computers store data both internally, in what is called
main memory, and externally, on auxiliary storage units. As a computer
processes data and instructions, it temporarily stores information internally,
usually on silicon random-access memory, or RAM, chips--often called
semiconductor memory. Usually mounted on the main circuit board inside the
computer or on peripheral cards that plug into the board, each RAM chip may
consist of as many as 16 million switches, called flip-flop switches, that
respond to changes in electric current. Each switch can hold one bit of data:
high voltage applied to a switch causes it to hold a 1; low voltage causes it
to hold a 0. This kind of internal memory is also called read/write
memory.
Another
type of internal memory consists of a series of read-only memory, or ROM,
chips. The switches of ROM chips are set when they are manufactured and are
unchangeable. The patterns on these chips correspond to commands and programs that
the computer needs in order to boot up, or ready itself for operation, and to
carry out basic operations. Because read-only memory is actually a combination
of hardware (microchips) and software (programs), it is often referred to as
firmware.
Other
devices that are sometimes used for main memory are magnetic-core memory and
magnetic-bubble memory. Unlike semiconductor memories, these do not lose their
contents if the power supply is cut off. Long used in mainframe computers,
magnetic-core memories are being supplanted by the faster and more compact
semiconductor memories in mainframes designed for high-speed applications.
Magnetic-bubble memory is used more often for auxiliary storage than for main
memory.
Auxiliary storage units supplement the main memory by holding parts of
programs that are too large to fit into the random-access memory at one time.
They also offer a more permanent and secure method for storing programs and
data.
Four
auxiliary storage devices--floppy disks, hard disks, magnetic tape, and
magnetic drums--store data by magnetically rearranging metal particles on
disks, tape, or drums. Particles oriented in one direction represent 1s, and
particles oriented in another direction represent 0s. Floppy-disk drives (which
"write" data on removable magnetic disks) can store from 140,000 to
2.8 million bytes of data on one disk and are used primarily in laptop and
personal computers. Hard disk drives contain nonremovable magnetic media and
are used with all types of computers. They access data very quickly and can
store from 10 million bytes (10 megabytes) of data to a few gigabytes (billion
bytes).
Magnetic-tape storage devices are usually used together with hard disk
drives on large computer systems that handle high volumes of constantly
changing data. The tape drives, which access data very slowly, regularly back
up, or duplicate, the data in the hard disk drives to protect the system
against loss of data during power failures or computer malfunctions.
magnetic-drum memories store data in the form of magnetized spots in
adjacent circular tracks on the surface of a rotating metal cylinder. They are
relatively slow and are rarely used today.
Optical
discs are nonmagnetic auxiliary storage devices that developed from compact-audio-disc
technology. Data is encoded on a disc as a series of pits and flat spaces,
called lands, the lengths of which correspond to different patterns of 0s and
1s. One removable 4 3/4-inch
(12-centimeter) disc contains a spiral track more than 3 miles (4.8 kilometers)
long, on which can be stored nearly a billion bytes (gigabyte) of information.
All of the text in this encyclopedia, for example, would fill only one fifth of
one disc. Read-only optical discs, whose data can be read but not changed, are
called CD-ROMs (compact disc-read-only memory). (See also Compact Disc.)
Recordable CD-ROM drives, called WORM (write-once/read-many) drives, are used
by many businesses and universities to periodically back up changing databases
and to conveniently distribute massive amounts of information to customers or
users.
Output devices let the
user see the results of the computer's data processing. The most common output
device is the video display terminal (VDT), or monitor, which uses a
cathode-ray tube (CRT) to display characters and graphics on a television-like
screen.
Modems (modulator-demodulators)
are input-output devices that allow computers to transfer data between each
other. A modem on one computer translates digital pulses into analog signals
(sound) and then transmits the signals through a telephone line or a
communication network to another computer. A modem on the computer at the other
end of the line reverses the process.
Printers
generate hard copy--a printed version of information stored in one of the
computer's memory systems. The three principal types of printers are
daisy-wheel, dot-matrix, and laser. Other types of printers include ink-jet
printers and thermal printers. (See also Photocopying.)
Software
A computer's operating system is the software that
allows all of the dissimilar hardware and software systems to work together. It
is often stored in a computer's ROM memory. An operating system consists of
programs and routines that coordinate operations and processes, translate the
data from different input and output devices, regulate data storage in memory,
allocate tasks to different processors, and provide functions that help
programmers write software.
Computers that use disk memory-storage systems are said to have disk
operating systems (DOS). MS-DOS is the most popular microcomputer operating
system. UNIX, a powerful operating system for larger computers, allows many
users and many different programs to gain access to a computer's processor at
the same time. Visual operating systems called GUIs (graphical user interfaces)
were designed to be easy to use, yet to give UNIX-like power and flexibility to
home and small-business users. Future operating systems will enable users to
control all aspects of the computer's hardware and software simply by moving
and manipulating their corresponding "objects," or graphical icons
displayed on the screen.
Sometimes programs other than the operating system are built into the
hardware, as is the case in dedicated computers or ROM chips. Most often,
however, programs exist independently of the computer. When such software is
loaded into a general-purpose computer, it automatically programs the computer
to perform a specific task--such as word processing, managing accounts and inventories,
or displaying an arcade game.
Programming.
Software is written by professionals known as computer programmers. Most
programmers in large corporations work in teams, with each person focusing on a
specific aspect of the total project. (The eight programs that run each craft
in the Space Shuttle program, for example, consist of a total of about half a
million separate instructions and were written by hundreds of programmers.) For
this reason, scientific and industrial software sometimes costs much more than
do the computers on which the programs run.
Generally, programmers create software by using the following
step-by-step development process:
(1)
Define the scope of the program by outlining exactly what the program will
do.
(2) Plan
the sequence of computer operations, usually by developing a flowchart (a
diagram showing the order of computer actions and data flow).
(3)
Write the code--the program instructions encoded in a particular programming
language.
(4) Test
the program.
(5)
Debug the program (eliminate problems in program logic and correct incorrect
usage of the programming language).
(6)
Submit the program for beta testing, in which users test the program
extensively under real-life conditions to see whether it performs
correctly.
Often
the most difficult step in program development is the debugging stage. Problems
in program design and logic are often difficult to spot in large programs,
which consist of hundreds of smaller units called subroutines or subprograms.
Also, though a program might work, it is considered to have bugs if it is
slower or less efficient than it should be. (The term bug was coined in the
early 1940s, when programmers looking for the cause of a mysterious malfunction
in the huge Mark I computer discovered a moth in a vital electrical switch.
Thereafter the programmers referred to their activity as debugging.)
Logic bombs, viruses, and worms. In an effort to sabotage other people's computers, some computer users
(sometimes called hackers) create software that can manipulate or destroy
another computer's programs or data. One such program, called a logic bomb,
consists of a set of instructions entered into a computer's software. When
activated, it takes control of the computer's programs. A virus attaches itself
to a program, often in the computer's operating system, and then copies itself
onto other programs with which it comes in contact. Viruses can spread from one
computer to another by way of exchanged disks or programs sent through
telephone lines. Worms are self-contained programs that enter a computer and
generate their own commands. Logic bombs, viruses, and worms, if undetected,
may be powerful enough to cause a whole computer system to crash.
Programming languages. On the first electronic computers, programmers had to reset switches and
rewire computer panels in order to make changes in programs. Although
programmers still must "set" (to 1) or "clear" (to 0)
millions of switches in the microchips, they now use programming languages to
tell the computer to make these changes.
There
are two general types of languages--low-level and high-level. Low-level
languages are similar to a computer's internal binary language, or machine
language. They are difficult for humans to use and cannot be used
interchangeably on different types of computers, but they produce the fastest
programs. High-level languages are less efficient but are easier to use because
they resemble spoken languages.
A
computer "understands" only one language--patterns of 0s and 1s. For
example, the command to move the number 255 into a CPU register, or memory
location, might look like this: 00111110 11111111. A program might consist of
thousands of such operations. To simplify the procedure of programming
computers, a low-level language called assembly language was developed by
assigning a mnemonic code to each machine-language instruction to make it
easier to remember and write. The above binary code might be written in
assembly language as: MVI A,0FFH. To the programmer this means "MoVe
Immediately to register A the value FF (hexadecimal for 255)." A program
can include thousands of these mnemonics, which are then assembled, or
translated, into binary machine code. High-level languages use easily remembered
English-language-like commands (such as PRINT, OPEN, GOTO, INCLUDE, and so on)
that represent frequently used groups of machine-language instructions. Entered
from the keyboard or from a program, these commands are intercepted by a
separate program--an interpreter or compiler--that translates the commands into
the binary code the computer uses. The extra step, however, causes programs to
run more slowly than do programs in low-level languages.
The
first commercial high-level language was called FLOW-MATIC and was devised in
the early 1950s by Grace Hopper, a U.S. Navy computer programmer. In 1954, as
computers were becoming an increasingly important scientific tool, IBM began
developing a language that would simplify the programming of complicated mathematical
formulas. Completed in 1957, FORTRAN (Formula Translating
system), became the first comprehensive high-level programming language. Its
importance was immediate and long-lasting, and it is still widely used today in
engineering and scientific applications.
FORTRAN
manipulated numbers and equations efficiently, but it was not suited for
business-related tasks, such as creating, moving, and processing data files.
COBOL (Common Business-Oriented Language) was
developed to address those needs. Based on FORTRAN, but with its emphasis
shifted to data organization and file-handling, COBOL became the most important
programming language for commercial and business-related applications and is
widely used today.
A
simplified version of FORTRAN, called BASIC (Beginner's All-purpose
Symbolic Instruction Code), was developed in the 1960s by
two professors at Dartmouth College. Considered too slow and inefficient for
professional use, BASIC was nevertheless simple to learn and easy to use, and
it became an important academic tool for teaching programming fundamentals to
non-professional computer users. The explosion of microcomputer use in the
late-1970s and 1980s transformed BASIC into a universal programming language.
Because almost all microcomputers are sold with some version of BASIC included,
millions of people now use the language, and tens of thousands of BASIC
programs are now in common use.
Hundreds
of computer programming languages (or language variants) exist today. Pascal is
a highly structured language that teaches good programming techniques and
therefore is often taught in universities. Another educational language, LOGO,
was developed to teach children mathematical and logical concepts. LISP (list
processing), developed to manipulate symbolic lists of recursive data,
is used in most artificial-intelligence programs. C, a fast and efficient
language used for operating systems and in many professional and
commercial-quality programs, has recently evolved into the computer world's
most powerful programming tool--C++. This object-oriented programming (OOP)
language lets programs be constructed out of self-contained modules of code and
data, called classes, that can be easily modified and reused in other products.
HISTORY OF THE COMPUTER
The ideas and inventions of many mathematicians,
scientists, and engineers paved the way for the development of the modern
computer. In a sense, the computer actually has three birth dates--one as a
mechanical computing device, in about 500 BC, another as a concept (1833), and the third as the modern electronic
digital computer (1946).
Calculating Devices
The first mechanical calculator, a system of
strings and moving beads called the abacus, was devised in Babylonia around 500
BC. The abacus provided the fastest method of
calculating until 1642, when the French scientist Blaise Pascal invented a
calculator made of wheels and cogs. When a units wheel moved one revolution
(past ten notches), it moved the tens wheel one notch; when the tens wheel
moved one revolution, it moved the hundreds wheel one notch; and so on.
Improvements on Pascal's mechanical calculator were made by such scientists and
inventors as Gottfried Wilhelm Leibniz, W.T. Odhner, Dorr E. Felt, Frank S.
Baldwin, and Jay R. Monroe. (See also Abacus; Calculator; Leibniz,
Gottfried Wilhelm; Pascal, Blaise.)
Beyond the Adding Machine
The concept of the modern computer was first
outlined in 1833 by the British mathematician Charles Babbage. His design of an
"analytical engine" contained all of the necessary elements of a
modern computer: input devices, a store (memory), a mill (computing unit), a
control unit, and output devices. The design called for more than 50,000 moving
parts in a steam-driven machine as large as a locomotive. Most of the actions
of the analytical engine were to be executed through the use of perforated
cards--an adaptation of a method that was already being used to control
automatic silk-weaving machines called Jacquard looms. Although Babbage worked
on the analytical engine for nearly 40 years, he never actually constructed a
working machine. (See also Babbage, Charles.)
Herman
Hollerith, an American inventor, spent the 1880s developing a calculating
machine that counted, collated, and sorted information stored on punched cards.
When cards were placed in his machine, they pressed on a series of metal pins
that corresponded to the network of potential perforations. When a pin found a
hole (punched to represent age, occupation, and so on), it completed an
electrical circuit and advanced the count for that category. First used to help
sort statistical information for the 1890 United States census, Hollerith's
"tabulator" quickly demonstrated the efficiency of mechanical data
manipulation. The previous census took seven and a half years to tabulate by
hand, but, using the tabulator, the simple count for the 1890 census took only
six weeks, and a full-scale analysis of all the data took only two and a half
years.
In 1896
Hollerith founded the Tabulating Machine Company to produce similar machines.
In 1924, after a number of mergers, the company changed its name to
International Business Machines Corporation (IBM). IBM made punch-card office
machinery the dominant business information system until the late 1960s, when a
new generation of computers rendered the punch card machines obsolete.
In the
late 1920s and 1930s, several new types of calculators were constructed.
Vannevar Bush, an American engineer, developed the differential analyzer, the
first calculator capable of solving differential equations. His machine
calculated with decimal numbers and therefore required hundreds of gears and
shafts to represent the various movements and relationships of the ten
digits.
In 1939
the American physicists John V. Atanasoff and Clifford Berry produced the
prototype of a computer based on the binary numbering system. Atanasoff
reasoned that binary numbers were better suited to computing than were decimal
numbers because the two digits 1 and 0 could easily be represented by electrical
circuits, which were either on or off. Furthermore, George Boole, a British
mathematician, had already devised a complete system of binary algebra that
might be applied to computer circuits. Developed in 1848, Boolean algebra
bridged the gap between mathematics and logic by symbolizing all information as
being either true or false. (See also Algebra, "Boolean
Algebra"; Boole.)
Electronic Digital Computers
The modern computer grew out of intense research
efforts mounted during World War II. The military needed faster ballistics
calculators, and British cryptographers needed machines to help break the
German secret codes.
As early
as 1941 the German inventor Konrad Zuse produced an operational computer, the
Z3, that was used in aircraft and missile design. The German government refused
to help him refine the machine, however, and the computer never achieved its
full potential.
A
Harvard mathematician named Howard Aiken directed the development of the
Harvard-IBM Automatic Sequence Controlled Calculator, later known as the Mark
I--an electronic computer that used 3,304 electromechanical relays as on-off
switches. Completed in 1944, its primary function was to create ballistics
tables to make Navy artillery more accurate.
The
first fully electronic computer, which used vacuum tubes rather than mechanical
relays, was so secret that its existence was not revealed until decades after
it was built. Invented by the English mathematician Alan Turing and in
operation by 1943, the Colossus was the computer that British cryptographers
used to break secret German military codes. Messages were encoded as symbols on
loops of paper tape, and the 2,000-tube computer compared them--at nearly
25,000 characters per second--with codes that had already been deciphered.
Because
Colossus was designed for only one task, the distinction as the first modern
general-purpose electronic computer properly belongs to ENIAC (Electronic
Numerical Integrator and Calculator). Designed by two American engineers, John
W. Mauchly and J. Presper Eckert, Jr., ENIAC went into service at the
University of Pennsylvania in 1946. Its construction was an enormous feat of
engineering--the 30-ton machine was 18 feet (5.5 meters) high and 80 feet (24
meters) long, and contained 17,468 vacuum tubes linked by 500 miles (800
kilometers) of wiring. ENIAC performed 100,000 operations per second, and its
first operational test included calculations that helped determine the
feasibility of the hydrogen bomb.
To
change ENIAC's instructions, or program, engineers had to rewire the machine.
The next computers were built so that programs could be stored in internal
memory and could be easily changed to adapt the computer to different tasks.
These computers followed the theoretical descriptions of the ideal
"universal" (general-purpose) computer first outlined by Turing and
later refined by John von Neumann, a Hungarian-born mathematician.
The
invention of the transistor in 1947 brought about a revolution in computer
development. Hot, unreliable vacuum tubes were replaced by small germanium
(later silicon) transistors that generated little heat yet functioned perfectly
as switches or amplifiers (see Transistor).
The
breakthrough in computer miniaturization came in 1958, when Jack Kilby, an
American engineer, designed the first true integrated circuit. His prototype
consisted of a germanium wafer that included transistors, resistors, and
capacitors--the major components of electronic circuitry. Using less expensive
silicon chips, engineers succeeded in putting more and more electronic
components on each chip. The development of large-scale integration (LSI) made
it possible to cram hundreds of components on a chip; very-large-scale
integration (VLSI) increased that number to hundreds of thousands; and
engineers project that ultra-large-scale integration (ULSI) techniques will
allow as many as 10 million components to be placed on a microchip the size of
a fingernail.
Another
revolution in microchip technology occurred in 1971 when the American engineer
Marcian E. Hoff combined the basic elements of a computer on one tiny silicon
chip, which he called a microprocessor. This microprocessor--the Intel
4004--and the hundreds of variations that followed are the dedicated computers
that operate thousands of modern products and form the heart of almost every
general-purpose electronic computer. (See also Microprocessor.)
PCs and other Revolutions
By the mid-1970s, microchips and microprocessors
had drastically reduced the cost of the thousands of electronic components
required in a computer. The first affordable desktop computer designed
specifically for personal use was called the Altair 8800 and was sold by Micro
Instrumentation Telemetry Systems in 1974. In 1977 Tandy Corporation became the
first major electronics firm to produce a personal computer. They added a
keyboard and CRT to their computer and offered a means of storing programs on a
cassette recorder. Soon afterward, a small company named Apple Computer,
founded by engineer Stephen Wozniak and entrepreneur Steven Jobs, began
producing a superior computer.
IBM
introduced its Personal Computer, or PC, in 1981. As a result of competition
from the makers of clones (computers that worked exactly like an IBM-PC), the
price of personal computers fell drastically. Today's personal computer is 400
times faster than ENIAC, 3,000 times lighter, and several million dollars
cheaper. In rapid succession computers have shrunk from tabletop to lap-top and
finally to palm size. With some personal computers, called pen-pads, people can
even write directly on an etched-glass, liquid-crystal screen using a small
electronic stylus, and words will appear on the screen in clean
typescript.
Virtual Reality
As personal computers became faster and more
powerful in the late 1980s, software developers discovered that they were able
to write programs as large and as sophisticated as those previously run only on
mainframes. The massive million-dollar flight simulators on which military and
commercial pilots trained were the first real-world simulations to be moved to
the personal computer.
Flight
simulators are perfect examples of programs that create a virtual reality, or a
computer-generated "reality" in which the user does not merely watch
but is able to actually participate. The user supplies input to the system by
pushing buttons or moving a yoke or joystick, and the computer uses real-world
data to determine the results of those actions. For example, if the user pulls
back on the flight simulator's yoke, the computer translates the action
according to built-in rules derived from the performance of a real airplane.
The monitor will show exactly what an airplanes viewscreen would show as it
begins to climb. If the user continues to climb without increasing the
throttle, the "virtual plane" will stall (as would a real plane) and
the "pilot" will lose control. Thus the user's physical actions are
immediately and realistically reflected on the computer's display. For all
intents and purposes, the user is flying--that is, the "plane" obeys
the same laws of nature, has the same mechanical capabilities, and responds to
the same commands as a real airplane.
Virtual
reality programs give users three essential capabilities-- immersion,
navigation, and manipulation. People must be immersed in the alternate reality,
not merely feel as if they are viewing it on a screen. To this end, some
programs require people to wear headphones, use special controllers or foot
pedals, or wear 3-D glasses. The most sophisticated means of immersing users in
a virtual reality program is through the use of head-mounted displays, helmets
that feed slightly different images to either eye and that actually move the
computer image in the direction that the user moves his or her head. Virtual
reality programs also create a world that is completely consistent internally.
Thus one can navigate one's way though that world as "realistically"
as in the real world. For example, a street scene will always show the same
doors and windows, which, though their perspective may change, is always
absolutely consistent internally. The most important aspect of a virtual
reality program is its ability to let people manipulate objects in that world.
Pressing a button may fire a gun, holding down a key may increase a plane's
speed, clicking a mouse may open a door, or pressing arrow keys may rotate an
object.
Many
amusement parks now have rides and attractions that use virtual reality
principles for creating exciting alternate realities for their audiences--for
example, a simulated ride in a spaceship, complete with near collisions and
enemy attacks. Acceleration and deceleration are simulated by pitching and
moving seats, all computer-controlled and cleverly coordinated with stereo
sound effects and wrap-around video displays.
Multimedia
In the early 1990s, manufacturers began producing
inexpensive CD-ROM drives that could access more than 650 megabytes of data
from a single disc. This development started a multimedia revolution that may
continue for decades. The term multimedia encompasses the computer's ability to
merge sounds, video, text, music, animations, charts, maps, etc., into
colorful, interactive presentations, a business advertising campaign, or even a
space-war arcade game.
Audio
and video clips require enormous amounts of storage space, and for this reason,
until recently, programs could not use any but the most rudimentary animations
and sounds. Floppy and hard disks were just too small to accommodate the
hundreds of megabytes of required data. The enormous storage potential of
CD-ROM changed all that. Driving simulations, for example, can now show actual
footage of the Indianapolis Speedway as the user plays the game. The
manufacturer first digitizes video scenes of the speedway and records the real
sounds of the racers as they circle the track. Those images and sounds are then
stored on a CD-ROM disc with the driving program itself. When a user runs the
simulation and turns his computerized car, for example, the program senses the
"turn" and immediately flashes the corresponding real sounds and
scenes on the screen. Likewise, when a driver's car approaches another car, a
video image of a real car is displayed on the screen. By using simultaneous
clips from several different media, the user's senses of sight, sound, and
touch are merged into an astonishingly real experience.
Faster
computers and the rapid proliferation of multimedia programs will probably
forever change the way people get information. The computer's ability to
instantly retrieve a tiny piece of information from the midst of a huge mass of
data has always been one of its most important uses. Since video and audio
clips can be stored alongside text on a single CD-ROM disc, a whole new way of
exploring a subject is possible. By using hyperlinks--a programming method by
which related terms, articles, pictures, and sounds are internally hooked
together--material can be presented to people so that they can peruse it in a
typically human manner, by association. For example, if you are reading about
Abraham Lincoln's Gettysburg Address and you want to read about the battle of
Gettysburg, you need only click on the highlighted hyperlink "battle of
Gettysburg." Instantly, the appropriate text, photos, and maps appear on the
monitor. "Pennsylvania" is another click away, and so on.
Encyclopedias, almanacs, collections of reference books, interactive games
using movie footage, educational programs, and even motion pictures with
accompanying screenplay, actor biographies, director's notes, and reviews make
multimedia one of the computer world's most exciting and creative fields.
The Information Superhighway
A computer network is the interconnection of many
individual computers, much as a road is the link between the homes and the
buildings of a city. Having many separate computers linked on a network
provides many advantages to organizations such as businesses and universities.
People may quickly and easily share files; modify databases; send memos called
E-mail, or electronic mail; run programs on remote mainframes; and get access
to information in databases that are too massive to fit on a small computer's
hard drive. Networks provide an essential tool for the routing, managing, and
storing of huge amounts of rapidly changing data.
The
Internet is a network of networks: the international linking of tens of
thousands of businesses, universities, and research organizations with millions
of individual users. It is what United States Vice-President Al Gore first
publicly referred to as the information superhighway. What is now known as the
Internet was originally formed in 1970 as a military network called ARPAnet
(Advanced Research Projects Agency network) as part of the Department of
Defense. The network opened to non-military users in the 1970s, when
universities and companies doing defense-related research were given access,
and flourished in the late 1980s as most universities and many businesses
around the world came on-line. In 1993, when commercial providers were first
permitted to sell Internet connections to individuals, usage of the network
exploded. Millions of new users came on within months, and a new era of
computer communications began.
Most
networks on the Internet make certain files available to other networks. These
common files can be databases, programs, or E-mail from the individuals on the
network. With hundreds of thousands of international sites each providing
thousands of pieces of data, it's easy to imagine the mass of raw data
available to users.
The
Internet is by no means the only way in which computer users can communicate
with others. Several commercial on-line services provide connections to members
who pay a monthly connect-time fee. CompuServe, America OnLine, Prodigy, Genie,
and several others provide a tremendous range of information and services,
including on-line conferencing, electronic mail transfer, program downloading,
current weather and stock market information, travel and entertainment
information, access to encyclopedias and other reference works, and electronic
forums for specific users' groups such as PC users, sports fans, musicians, and
so on.
Artificial Intelligence and Expert Systems
The standard definition of artificial intelligence
is "the ability of a robot or computer to imitate human actions or skills
such as problem solving, decision making, learning, reasoning, and
self-improvement." Today's computers can duplicate some aspects of
intelligence: for example, they can perform goal-directed tasks (such as finding
the most efficient solution to a complex problem), and their performance can
improve with experience (such as with chess-playing computers). However, the
programmer chooses the goal, establishes the method of operation, supplies the
raw data, and sets the process in motion. Computers are not in themselves
intelligent.
It is
widely believed that human intelligence has three principal components: (1)
consciousness, (2) the ability to classify knowledge and retain it, and (3) the
ability to make choices based on accumulated memories. Expert systems, or
computers that mimic the decision-making processes of human experts, already
exist and competently perform the second and third aspects of intelligence.
INTERNIST is a computer system that diagnoses 550 diseases and disorders with
an accuracy that rivals that of human doctors. PROSPECTOR is an expert system
that aids geologists in their search for new mineral deposits. Using
information obtained from maps, surveys, and questions that it asks geologists,
PROSPECTOR compares the new data to stored information about existing ore
deposits and predicts the location of new deposits.
As
computers get faster, as engineers devise new methods of parallel processing
(in which several processors simultaneously work on one problem), and, as vast
memory systems (such as CD-ROM) are perfected, consciousness--the final step to
intelligence--is no longer inconceivable. English scientist Alan Turing devised
the most famous test for assessing computer intelligence. The "Turing
test" is an interrogation session in which a human asks questions of two
entities, A and B, which he or she can't see. One entity is a human, and the
other is a computer. The interrogator must decide, on the basis of the answers,
which one, A or B, is the human and which the computer. If the computer
successfully disguises itself as a human--and it or the human may lie during
the questioning--then the computer has proven itself intelligent. (See also
Artificial Intelligence.)
The Future of Computers
Research and development in the computer world
moves simultaneously along two paths--hardware designs and software
innovations. Work in each area alternately influences the other.
Many
hardware systems are reaching natural limitations. RAM chips that can store 64
megabits (millions of 0s or 1s) are currently being tested, but the connecting
circuitry is so narrow that its width must be measured in atoms. These circuits
are susceptible to temperature changes and to stray radiation in the
atmosphere, both of which could cause a program to crash (fail) or lose data.
Newer microprocessors have so many millions of switches etched into them that
the heat they generate has become a serious problem. For these and other
reasons, many researchers feel that the future of computer hardware might not
be in further miniaturization, but in radical new architectures, or computer
designs. Almost all of today's computers process information serially, one
element at a time. Massively parallel computers--consisting of hundreds of
small, simple, but structurally linked microchips--break tasks into their
smallest units and assign each unit to a separate processor. With many
processors simultaneously working on a given task, the problem can be solved
much more quickly. One design, called the Thinking Machine, uses several
thousand inexpensive microprocessors and can outperform many of today's
supercomputers.
Some
researchers predict the development of biochips, protein molecules sandwiched
between glass and metal, that would have a vastly greater storage capacity than
current technology allows. Several research labs are even now studying the
feasibility of biocomputers that would contain a mixture of organic and
inorganic components.
Several
hundred thousand computer-controlled robots currently work on industrial
assembly lines in Japan and America. They consist of four major elements:
sensors (to determine position or environment), effectors (tools to carry out
an action), control systems (a digital computer and feedback sensors), and a
power system. As computers become more efficient and artificial intelligence
programs become more sophisticated, robots will be able to perform more
difficult and more human-like tasks. Robots currently being built by
researchers at Carnegie-Mellon University have been used in scientific
explorations too dangerous for humans to perform, such as descending into
active volcanoes or exploring nuclear sites in which radiation leakage has
occurred.
As
exciting as all of the hardware developments are, they are nevertheless
dependent on well-conceived and well-written software. Software controls the
hardware, uses it efficiently, and forms an interface between the computer and
the user. Software is becoming increasingly user-friendly--easy to use by
non-computer professional users--and intelligent--able to adapt to a specific
user's personal habits. A few word-processing programs now learn their user's
writing style and offer suggestions; some game programs learn by experience and
become more difficult opponents the more they are played. Future programs
promise to adapt themselves to their user's personality and work habits so that
the term personal computing will take on an entirely new meaning.
CAREERS IN THE COMPUTER FIELD
Computer-related jobs are among the most rapidly
growing employment segments in the United States. Economic studies project that
computer equipment will represent about one-fifth of all capital expenditures
by businesses in the 1990s. Hundreds of thousands of people will be needed to
manufacture, operate, program, and manage new equipment. The most sought-after
computer specialists will probably be systems analysts, programmers, and
operators.
Systems
analysts develop methods for computerizing businesses and scientific centers.
They and computer consultants also improve the efficiency of systems already in
use. Computer security specialists will be in great demand to help protect the
integrity of the huge information banks being developed by businesses and the
government.
Programmers write the software that transforms a machine into a personal
tool that not only is useful for increasing productivity but also can enlighten
and entertain. Applications programmers write commercial programs to be used by
businesses, in science centers, and in the home. Systems programmers write the
complex programs that control the inner-workings of the computer. Many
specialty areas exist within these two large groups, such as database and
telecommunication programmers.
As more
small- and medium-sized businesses become computerized, they will require more
people to operate their systems. Computer operators will need to handle several
types of computers and be familiar with a diversified range of applications,
such as database managers, spreadsheets, and word processors.
Other
important careers in this rapidly expanding field include computer scientists,
who perform research and teach at universities; hardware designers and
engineers, who work in areas such as microchip and peripheral equipment design;
and information-center or database administrators, who manage the information
collections developed by businesses or data banks.
Various
support careers also exist. Technical writers, computer-based training
specialists, and operations managers do not need extremely technical
backgrounds to work in their fields; they need only an expertise in their
original fields, a knowledge of computers, and a desire to share their
knowledge with others. (See also Automation; Electronics; Information
Theory.)
Computer Terms
arithmetic/logic unit (ALU). The section of the central processing unit that performs arithmetic and
logic operations. binary code. A coding system that uses two alternative elements--0 or 1, TRUE or
FALSE, voltage or no voltage--to represent numbers, characters, and symbols. bit. A binary digit. The smallest unit of information
that a computer can handle, represented by a single 0 or 1. byte. A group of eight bits (representing, for example,
a number or letter) that the computer operates on as a single unit. cathode-ray tube (CRT). A vacuum tube,
like that in a television, that projects a beam of high-speed electrons onto a
fluorescent screen in order to display information to the computer user. central processing unit (CPU). The main part
of a computer. Contains internal memory, an arithmetic/logic unit, and control
circuitry and performs data-processing and timing and controlling functions. chip, or microchip. A thin slice of silicon
containing an integrated circuit. control unit. The part of the central processing unit that determines the sequence of
computer activities, interprets instructions, and controls the way in which
those instructions are carried out. database. A collection of information organized for rapid search and retrieval. data processing. The converting of raw data
to machine-readable form and its subsequent processing (as storing, updating,
combining, rearranging, or printing) by a computer. disk drive. A device that rotates a
magnetic storage disk and that can record data on the disk and read data from
the disk. floppy disk. A thin
flexible plastic disk that stores data in the form of magnetic patterns on its
surface. Used primarily in microcomputers. flowchart. A diagram that uses connecting lines and a set of conventional symbols
to show the sequence of operations and the flow of data in a computer program. hardware. The physical components of a
computer system, such as the chips, disk drives, monitor, and other devices.
Distinguished from software. input. Data to be processed that is entered into the computer from a keyboard,
disk drive, or other input device. integrated
circuit (IC). An electronic circuit containing thousands of
electronic components combined on one chip. interface. The hardware and software that enable a user to interact with a computer
(called a user interface) or that enable two computer systems to interact. logic circuit. An electronic switching
circuit that performs a logic operation; its binary output is entirely
determined by the combination of binary input. memory. A storage area in which a computer saves data and
from which it retrieves data. microprocessor. A single chip containing all the components found in a computer's
central processing unit. network. A system of computers, terminals, and databases connected by
communications lines. Allows users of different types of computers to exchange
data and to make use of special programs or of very large computers. Scopes
range from local-area networks (LANs) to international networks. operating system. A linked series of programs
that controls, assists, and supervises all other programs on a computer system
and that allows dissimilar hardware systems to work together. output. Data that has been processed by the computer and
sent to a screen, printer, or other output device. program. A step-by-step series of
instructions directing the computer to carry out a sequence of actions in order
to perform an operation or to solve a problem. random-access memory (RAM). A temporary
computer memory system in which data can be stored and from which data can be
quickly retrieved. read-only memory (ROM). A permanent computer memory system containing data and instructions that
can be retrieved and used but never altered. simulation. A computer representation of a real-life system or process that imitates
the behavior of the real system under a variety of conditions. software. Instructions or programs
used by a computer to do its work. Distinguished from hardware. terminal. A device with a keyboard for
inputting data to a computer and a display screen for receiving data from the
computer. word processing. An
automated means of creating and editing text. Uses computer programs that
accept input (text) from a keyboard or from computer memory, enable the user to
manipulate the text, and can send the original or revised text to a display
screen or printer.
Some Major Figures in Computer History
Some prominent persons are not included below
because they are covered in the main text of this article or in other articles
in Compton's Encyclopedia.
Aiken, Howard
(1900-73). American mathematician who in 1944, with the engineers Clair D.
Lake, B.M. Durfee, and F.E. Hamilton, invented an early electromechanical
computer, the Mark I--the first large-scale automatic calculator. Completed an
improved all-electric computer, Mark II, in 1947. Atanasoff, John V. (born 1903). American
physicist who, with Clifford Berry, in 1939 built a prototype of an
electromechanical digital computer called the ABC (Atanasoff-Berry
Computer)--the first computer that used a binary numbering system. Bush, Vannevar (1890-1974). American
electrical engineer who in 1928 designed the differential analyzer, the first
calculator capable of solving differential equations. Also developed the Rapid
Selector, a device that uses a code and microfilm to facilitate information
retrieval. Byron, Augusta Ada (1815-52). English mathematician who was countess of Lovelace. Sometimes
called the first computer programmer because she created a program for Charles
Babbage's proposed analytical engine, forerunner of the modern digital
electronic computer (see Babbage, Charles). Cray, Seymour (1925-96). American
electronics engineer and preeminent designer of supercomputers. In 1957 he
helped found Control Data Corporation. In 1972 he founded Cray Research, Inc.,
which in 1976 developed the Cray-1 supercomputer--the fastest and most powerful
computer of the time. Eckert, J. Presper, Jr. (1919-95). American engineer. Coinventor, with John W. Mauchly, of the first
general-purpose all-electronic digital computer, ENIAC (Electronic Numerical
Integrator and Calculator). Completed in 1946, it was the prototype for most
computers in use today. In 1948 they completed Binac (Binary Automatic
Computer), which stored information on magnetic tape rather than on punch
cards. Their manufacturing firm merged into Sperry Rand Corporation. Hoff, Marcian E. (born 1937). American
engineer who in 1971 designed the first microprocessor, combining all of the
essential elements of a computer's central processing unit on a single silicon
microchip. Hollerith, Herman (1860-1929). American inventor who in 1889 patented a tabulating machine
that recorded statistics by electrically reading punched cards. In 1896 he
organized the Tabulating Machine Company, which, through subsequent mergers,
grew into the International Business Machines Corporation (IBM). Hopper, Grace (1906-92). American
mathematician and United States Navy officer who first conceived of compilers.
Developed the first commercial high-level programming language, called
FLOW-MATIC--a major forerunner of COBOL. Also worked with Howard Aiken on Mark
I. Kilby, Jack (born 1923).
American engineer working for Texas Instruments, Inc., who in 1958 designed the
first true integrated circuit. Mauchly, John
W. (1907-80). American physicist and engineer.
Coinventor in 1946, with J. Presper Eckert, Jr., of ENIAC and later models
Binac and Univac I. Noyce, Robert (1927-90). Electronics physicist and founder of Intel Corporation. In
1959, six months after Jack Kilby designed an integrated circuit, Noyce
introduced a more practical version of the silicon chip. His invention brought
about the PC revolution of the 1980s and led to the extensive use of microchips
in consumer products. From 1988 headed Sematech. Turing, Alan M. (1912-54). English
mathematician and logician whose theoretical universal computer, called the
Turing machine, provided the theoretical basis for the digital computers
developed in the 1940s. Designed the first all-electric computer, the Colossus,
in the early 1940s. Von Neumann, John (1903-57). Hungarian-born American mathematician who did much pioneering
work in the areas of logical design of computers, methods of programming, the
problem of designing reliable machines using unreliable components, machine
imitation of randomness, and the problem of constructing machines that can
reproduce their own kind. Zuse, Konrad (1910-95). German inventor who built several working computers,
including the first automatically controlled calculator, during World War II.
An unreceptive wartime government hampered his attempts to build what would
have been the first modern electronic general-purpose computer.
This article was contributed by Gary Masters,
former managing editor, Microsoft Press; former technical editor and writer,
Tandy Corporation; winner of the Southwest Technical Writer's Association Award
for Excellence; and author of books about computers.
FURTHER RESOURCES FOR COMPUTER
Aho, Alfred, and Ullman, Jeffrey. Foundations of Computer Science (Scientific American Library, 1993). Asimov, Isaac. How Did We Find Out About
Computers? (Walker, 1984). Augarten, Stan. Bit by Bit: An Illustrated History of Computers (Ticknor & Fields,
1984). Ceruzzi, Paul. The
Computer Revolution (ABC, 1994). Curran, Susan
and Curnow, Ray. Overcoming Computer
Illiteracy: A Friendly Introduction to Computers (Penguin, 1984). Freedman, Alan. The Computer Glossary: The
Complete Illustrated Desk Reference, 4th ed. (AMACOM, 1989). Greenia, M.W. History of Computing
(Lexikon Services, 1993). Hafner, Katie, and Markoff,
John. Cyberpunk: Outlaws and Hackers on the Computer
Frontier (Simon and Schuster, 1992). Kaplan, Andrew. Careers for Computer Buffs (Houghton, 1992). Kauffmann, William, III, and Smarr, Larry. Supercomputing (Scientific American Library, 1993). Levy, Steven. Hackers (Dell, 1985). Long, Larry, and Long, Nancy. Computers, 3rd
ed. (Prentice, 1994). McNeill, Daniel, and
Freiberger, Paul. Fuzzy Logic (Simon and
Schuster, 1993). Rheingold, Howard. Virtual Reality: Exploring the Brave New Technologies (Simon &
Schuster, 1991). Rosch, Winn. The Winn L. Rosch PC Upgrade Bible (Brady, 1991). Silverman, Gordon and Turkiew, D.B.
Computers and Computer Languages (McGraw, 1988). Time-Life Books. Computer Basics; Software;
Computer Images; Computer Security; Input-Output (Time-Life, 1985; 1985; 1986;
1986; 1986). Veit, Stan. History of the
Personal Computer (WorldComm, 1993). [1]
1.
Comdata Observe (1-2), 1987H, 1988G -
1408H, 1409H
2.
Comdata Coverage (1), 1988G - 1408H,1409H
3.
Comdata Events (Information System), 1988G,
1989G - 1408H, 1409H 1410H
4.
Catalogue 1996G by I.S. SDM; 1996g (Charts)
5.
Education Activity and View Coverage;
1996g (Charts)
6.
Regular Project..; 1996g (Charts)
7.
Challenge Task I (Business General
Basics); 1996g (Charts)
8.
Challenge Task II (Understanding Data
Processing); 1996g (Charts)
9.
Normal View and Check Coverage; 1996g (Charts)
10. Introduction to
Information Technology ( Real Life Business); 1996g
11. Business Concept and View
Points (Part I); 1996g
12. Business Concept and View
Points (Part II); 1996g
13. Marketing Strategy for
Success; 1996g
14. Basic Rules For
Information Management; 1996g
15. Organization Management
and Administration Coverage; 1996g (CT
iii)
16. An Entrance to Next
Century; 1996g (CT
vi)
17. Survival in Business by
an Easy Procedures; 1996g (CT x)
18. Monitoring Project
Planning and Facilities Update; 1996g (CT xx)
19. Project’s Activities and
Related Tasks; 1996g
20. Join the Competition and
Win the Challenge; 1996g (CT xxv)
21. Directions of Management
and Processing; 1996g (CT xxx)
22. Productiveties
Improvement and Getting Update; 1996g (CT xxxv)
23. Culture Effect in
Marketing Business; 1996g (CT xxxx)
24. Efficient Methods of
Management Administration; 1997g (CT xxxxx)
25. Creating Procedures to
Get Best Project Processing; 1997g (CT 100)
26. Meet the Changing Demands
in the Market; 1997g (Acceptance Package to the Customer) (CT
200)
27. Windows to the business
in the Market; 1997g (CT 222)
28. Sort of Existing
Business - 0X 1997g (Chart) (CT
999)
29. Access All the Authorized
Channels by an Ease
30. A little Moment in Management
(Information Technology Systems) 1997G
31. Major and Minor
Activities Coverage 1997G (CT 2000)
32. Way of Organizing the
work (Information Technology Systems)
1997G
33. Dealing Right to get
your Rights (I.T.) Industrial Engineering)
1998G
34. Simple Ways to Project
Activities 1998G
35. Packaging Systems and
Quality Packing (I.T. Industrial Engineering) 1998G
36. Academic and Non
Academic Business (Industrial Engineering)
1998G
37. SDM-IE Newsletters –01- 1998G-1999G
[1]Excerpted
from Compton's Interactive Encyclopedia Deluxe. Copyright © 1994, 1995,
1996, 1997 The Learning Company, Inc. All Rights Reserved.