What are computers?
Computers are machines that perform
tasks or calculations according to a set of instructions, or programs. The first fully electronic computers, introduced
in the 1940s, were huge machines that required teams of people to operate.
Compared to those early machines, today's computers are amazing. Not only are
they thousands of times faster, they can fit on your desk, in your lap, or even
in your pocket.
Computers work through an interaction
of hardware and software. Hardware refers to the parts
of a computer that you can see and touch, including the case and everything
inside it. The most important piece of hardware is a tiny rectangular chip
inside your computer called the central processing unit
(CPU), or microprocessor. It's the
"brain" of your computer—the part that translates instructions and
performs calculations. Hardware items such as your monitor, keyboard, mouse,
printer, and other items are often called hardware devices,
or devices.
Software
refers to the instructions, or programs, that tell the hardware what to do. A
word processing program that you can use to write letters on your computer is a
type of software. The operating system (OS) is software that manages your
computer and the devices connected to it. Two well-known operating systems are Windows and Macintosh
operating system. Your computer uses the Windows
operating system.
Types of computers
Computers range in size and
capability. At one end of the scale are supercomputers,
very large computers with thousands of linked microprocessors that perform
extremely complex calculations. At the other end are tiny computers embedded in
cars, TVs, stereo systems, calculators, and appliances. These computers are
built to perform a limited number of tasks.
The personal
computer, or PC, is designed to be used by
one person at a time. This section describes the various kinds of personal
computers: desktops, laptops, handheld computers, and Tablet PCs.
Desktop computers
Laptop
computers
Laptop computers
are lightweight mobilje PCs with a thin screen. They are often called notebook computers because of their small size. Laptops
can operate on batteries, so you can take them anywhere. Unlike desktops,
laptops combine the CPU, screen, and keyboard in a single case. The screen
folds down onto the keyboard when not in use.
Laptop
computer
Handheld computers
Handheld computers, also called personal
digital assistants (PDAs), are battery-powered computers small enough to
carry almost anywhere. Ajlthough not as powerful as desktops or laptops,
handhelds are useful for scheduling appointments, storing addresses and phone
numbers, and playing games. Some have more advanced capabilities, such as
making telephone calls or accessing the Internet. Instead of keyboards,
handhelds have touch screens that you use with your finger or a stylus (a pen-shaped pointing tool).
Handheld computer
Tablet PCs
Tablet PCs are mobile PCs that combine features of laptops
and handhelds. Like laptops, they're powerful and have a built-in screen. Like
handhelds, they allow you to write notes or draw pictures on the screen,
usually with a tablet pen instead of a stylus. They can also convert your
handwriting into typed text. Some Tablet PCs are “convertibles” with a screen
that swivels and unfolds to reveal a keyboard underneath.
Tablet PC
What can you do with computers?
In the workplace, many people use
computers to keep records, analyze data, do research, and manage projects. At
home, you can use computers to find information, store pictures and music,
track finances, play games, and communicate with others—and those are just a
few of the possibilities.
You can also use your computer to
connect to the Internet, a network that links
computers around the world. Internet access is available for a monthly fee in
most urban areas, and increasingly, in less populated areas. With Internet
access, you can communicate with people all over the world and find a vast
amount of information.
Here are some of the most popular things to do with computers:
The web
The World Wide Web
(usually called the Web, or web)
is a gigantic storehouse of information. The web is the most popular part of
the Internet, partly because it displays most information in a visually
appealing format. Headlines, text, and pictures can be combined on a single webpage—much like a page in a magazine—along with sounds
and animation. A website is a collection of
interconnected webpages. The web contains millions of websites and billions of
webpages.
Example of a webpage (Microsoft Game Studios)
Surfing the
web means exploring it. You can find information on the web about almost any
topic imaginable. For example, you can read news stories and movie reviews,
check airline schedules, see street maps, get the weather forecast for your
city, or research a health condition. Most companies, government agencies,
museums, and libraries have websites with information about their products,
services, or collections. Reference sources, such as dictionaries and
encyclopedias, are also widely available.
The web is also a shopper's delight.
You can browse and purchase products—books, music, toys, clothing, electronics,
and much more—at the websites of major retailers. You can also buy and sell
used items through websites that use auction-style bidding.
For information about how to explore the Internet and the web,
see Exploring
the Internet.
E‑mail
E‑mail
(short for electronic mail) is a convenient way to
communicate with others. When you send an e‑mail message, it arrives almost
instantly in the recipient's e‑mail inbox. You can send e‑mail to many people
simultaneously, and you can save, print, and forward e‑mail to others. You can
send almost any type of file in an e‑mail message, including documents,
pictures, and music files. And with e‑mail, you don't need a stamp! See Getting
started with e‑mail.
Instant messaging
Instant messaging is like having a
real-time conversation with another person or a group of people. When you type
and send an instant message, the message is immediately visible to all
participants. Unlike e‑mail, all participants have to be online (connected to
the Internet) and in front of their computers at the same time. Communicating
by means of instant messaging is called chatting.
Pictures, music, and movies
If you have a digital camera, you can
move your pictures from the camera to your computer. Then you can print them,
create slide shows, or share them with others by e‑mail or by posting them on a
website. (To learn more about what you can do with photos, see Working
with digital pictures .) You can also listen to music on your computer,
either by importing (transferring to your computer) music from audio CDs or by
purchasing songs from a music website. Or, tune in to one of the thousands of
radio stations that broadcast over the Internet. If your computer comes with a
DVD player, you can watch movies.
Gaming
Do you like to play games? Thousands
of computer games in every conceivable category are available to entertain you.
Get behind the wheel of a race car, battle frightening creatures in a dungeon,
or control civilizations and empires! Many games allow you to compete with
other players around the world through the Internet. Windows includes a variety of card games, puzzle
games, and strategy games (see Learn
about games in Windows Vista).
The Types Of Computers: Analog and Hybrid (classification based on operational
principle)
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Types of Computers
I,
Computer: Definition
A computer is a
machine that can be programmed to manipulate symbols. Its principal
characteristics are:
Therefore
computers can perform complex and repetitive procedures quickly, precisely
and reliably. Modern computers are electronic and digital. The actual
machinery (wires, transistors, and circuits) is called hardware; the
instructions and data are called software. All general-purpose computers
require the following hardware components:
In addition to
these components, many others make it possible for the basic components to
work together efficiently. For example, every computer requires a bus that
transmits data from one part of the computer to another.
II, Computer
sizes and power
Computers can
be generally classified by size and power as follows, though there is
considerable overlap:
Supercomputer and Mainframe
Supercomputer is a broad term for one of
the fastest computers currently available. Supercomputers are very expensive
and are employed for specialized applications that require immense amounts of
mathematical calculations (number crunching). For example, weather
forecasting requires a supercomputer. Other uses of supercomputers scientific
simulations, (animated) graphics, fluid dynamic calculations, nuclear energy
research, electronic design, and analysis of geological data (e.g. in
petrochemical prospecting). Perhaps the best known supercomputer manufacturer
is Cray Research.
Mainframe was a term originally referring
to the cabinet containing the central processor unit or "main
frame" of a room-filling Stone Age batch machine. After the emergence of
smaller "minicomputer" designs in the early 1970s, the traditional
big iron machines were described as "mainframe computers" and
eventually just as mainframes. Nowadays a Mainframe is a very large and
expensive computer capable of supporting hundreds, or even thousands, of
users simultaneously. The chief difference between a supercomputer and a
mainframe is that a supercomputer channels all its power into executing a few
programs as fast as possible, whereas a mainframe uses its power to execute
many programs concurrently. In some ways, mainframes are more powerful than
supercomputers because they support more simultaneous programs. But
supercomputers can execute a single program faster than a mainframe. The
distinction between small mainframes and minicomputers is vague, depending
really on how the manufacturer wants to market its machines.
Minicomputer
It is a
midsize computer. In the past decade, the distinction between large
minicomputers and small mainframes has blurred, however, as has the
distinction between small minicomputers and workstations. But in general, a
minicomputer is a multiprocessing system capable of supporting from up to 200
users simultaneously.
Workstation
It is a type of computer used for engineering applications (CAD/CAM), desktop
publishing, software development, and other types of applications that
require a moderate amount of computing power and relatively high quality
graphics capabilities. Workstations generally come with a large,
high-resolution graphics screen, at large amount of RAM, built-in network
support, and a graphical user interface. Most workstations also have a mass
storage device such as a disk drive, but a special type of workstation,
called a diskless workstation, comes without a disk drive. The most common
operating systems for workstations are UNIX and Windows NT. Like personal
computers, most workstations are single-user computers. However, workstations
are typically linked together to form a local-area network, although they can
also be used as stand-alone systems.
N.B.: In networking,
workstation refers to any computer connected to a local-area network. It
could be a workstation or a personal computer.
Personal
computer: It can be defined as a small, relatively inexpensive computer
designed for an individual user. In price, personal computers range anywhere
from a few hundred pounds to over five thousand pounds. All are based on the
microprocessor technology that enables manufacturers to put an entire CPU on
one chip. Businesses use personal computers for word processing, accounting,
desktop publishing, and for running spreadsheet and database management
applications. At home, the most popular use for personal computers is for
playing games and recently for surfing the Internet.
Personal
computers first appeared in the late 1970s. One of the first and most popular
personal computers was the Apple II, introduced in 1977 by Apple Computer.
During the late 1970s and early 1980s, new models and competing operating
systems seemed to appear daily. Then, in 1981, IBM entered the fray with its
first personal computer, known as the IBM PC. The IBM PC quickly became the
personal computer of choice, and most other personal computer manufacturers
fell by the wayside. P.C. is short for personal computer or IBM PC. One of
the few companies to survive IBM's onslaught was Apple Computer, which
remains a major player in the personal computer marketplace. Other companies
adjusted to IBM's dominance by building IBM clones, computers that were
internally almost the same as the IBM PC, but that cost less. Because IBM
clones used the same microprocessors as IBM PCs, they were capable of running
the same software. Over the years, IBM has lost much of its influence in
directing the evolution of PCs. Therefore after the release of the first PC
by IBM the term PC increasingly came to mean IBM or IBM-compatible personal
computers, to the exclusion of other types of personal computers, such as
Macintoshes. In recent years, the term PC has become more and more difficult
to pin down. In general, though, it applies to any personal computer based on
an Intel microprocessor, or on an Intel-compatible microprocessor. For nearly
every other component, including the operating system, there are several
options, all of which fall under the rubric of PC
Today, the
world of personal computers is basically divided between Apple Macintoshes
and PCs. The principal characteristics of personal computers are that they
are single-user systems and are based on microprocessors. However, although
personal computers are designed as single-user systems, it is common to link
them together to form a network. In terms of power, there is great variety.
At the high end, the distinction between personal computers and workstations
has faded. High-end models of the Macintosh and PC offer the same computing
power and graphics capability as low-end workstations by Sun Microsystems,
Hewlett-Packard, and DEC.
III,
Personal Computer Types Actual personal computers can
be generally classified by size and chassis / case. The chassis or case is
the metal frame that serves as the structural support for electronic
components. Every computer system requires at least one chassis to house the
circuit boards and wiring. The chassis also contains slots for expansion
boards. If you want to insert more boards than there are slots, you will need
an expansion chassis, which provides additional slots. There are two basic
flavors of chassis designs–desktop models and tower models–but there are many
variations on these two basic types. Then come the portable computers that
are computers small enough to carry. Portable computers include notebook and
subnotebook computers, hand-held computers, palmtops, and PDAs.
Tower model The term refers to a computer in which the power supply,
motherboard, and mass storage devices are stacked on top of each other in a
cabinet. This is in contrast to desktop models, in which these components are
housed in a more compact box. The main advantage of tower models is that
there are fewer space constraints, which makes installation of additional
storage devices easier.
Desktop
model A
computer designed to fit comfortably on top of a desk, typically with the
monitor sitting on top of the computer. Desktop model computers are broad and
low, whereas tower model computers are narrow and tall. Because of their
shape, desktop model computers are generally limited to three internal mass
storage devices. Desktop models designed to be very small are sometimes
referred to as slimline models.
Notebook
computer An
extremely lightweight personal computer. Notebook computers typically weigh
less than 6 pounds and are small enough to fit easily in a briefcase. Aside
from size, the principal difference between a notebook computer and a
personal computer is the display screen. Notebook computers use a variety of
techniques, known as flat-panel technologies, to produce a lightweight and
non-bulky display screen. The quality of notebook display screens varies
considerably. In terms of computing power, modern notebook computers are
nearly equivalent to personal computers. They have the same CPUs, memory
capacity, and disk drives. However, all this power in a small package is
expensive. Notebook computers cost about twice as much as equivalent
regular-sized computers. Notebook computers come with battery packs that
enable you to run them without plugging them in. However, the batteries need
to be recharged every few hours.
Laptop
computer A small, portable computer -- small enough
that it can sit on your lap. Nowadays, laptop computers are more frequently
called notebook computers.
Subnotebook
computer A
portable computer that is slightly lighter and smaller than a full-sized
notebook computer. Typically, subnotebook computers have a smaller keyboard
and screen, but are otherwise equivalent to notebook computers.
Hand-held
computer A portable computer that is
small enough to be held in one’s hand. Although extremely convenient to
carry, handheld computers have not replaced notebook computers because of
their small keyboards and screens. The most popular hand-held computers are
those that are specifically designed to provide PIM (personal information
manager) functions, such as a calendar and address book. Some manufacturers
are trying to solve the small keyboard problem by replacing the keyboard with
an electronic pen. However, these pen-based devices rely on handwriting
recognition technologies, which are still in their infancy. Hand-held
computers are also called PDAs, palmtops and pocket computers.
Palmtop A small computer that literally fits in your palm.
Compared to full-size computers, palmtops are severely limited, but they are
practical for certain functions such as phone books and calendars. Palmtops
that use a pen rather than a keyboard for input are often called hand-held
computers or PDAs. Because of their small size, most palmtop computers do not
include disk drives. However, many contain PCMCIA slots in which you can
insert disk drives, modems, memory, and other devices. Palmtops are also
called PDAs, hand-held computers and pocket computers.
PDA Short for personal digital assistant, a handheld device
that combines computing, telephone/fax, and networking features. A typical
PDA can function as a cellular phone, fax sender, and personal organizer.
Unlike portable computers, most PDAs are pen-based, using a stylus rather
than a keyboard for input. This means that they also incorporate handwriting
recognition features. Some PDAs can also react to voice input by using voice
recognition technologies. The field of PDA was pioneered by Apple Computer,
which introduced the Newton MessagePad in 1993. Shortly thereafter, several
other manufacturers offered similar products. To date, PDAs have had only
modest success in the marketplace, due to their high price tags and limited
applications. However, many experts believe that PDAs will eventually become
common gadgets.
PDAs are also called palmtops,
hand-held computers and pocket computers.
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Apart
from this, computers are also categorized on the basis of physical structures
and the purpose of their use. Based on Capacity, speed and reliability they can
be divided into three categories of computers:
1. The Mainframe Computer – These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously.
2. The Microcomputer – These are the most frequently used computers better known by the name of “Personal computers”. This is the type of computer meant for public use. Other than Desktop Computer the choice ranges as follows:
1. The Mainframe Computer – These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously.
2. The Microcomputer – These are the most frequently used computers better known by the name of “Personal computers”. This is the type of computer meant for public use. Other than Desktop Computer the choice ranges as follows:
·
Personal
Digital Computer
·
Tablet
PC
·
Towers
·
Work
Stations
·
Laptops
·
Hand
Held Computer
3. The Mini computer – Mini computers like the mainframe computers are used by
business organization. The difference being that it can support the
simultaneous working of up to 100 users and is usually maintained in business
organizations for the maintenance of accounts and finances.
Yet another category of computer is the Super Computers. It is somewhat similar to mainframe computers and is used in economic forecasts and engineering designs. Today life without computers is inconceivable. Usage of different types of computers has made life both smooth and fast paced.
Yet another category of computer is the Super Computers. It is somewhat similar to mainframe computers and is used in economic forecasts and engineering designs. Today life without computers is inconceivable. Usage of different types of computers has made life both smooth and fast paced.
The
Generator of computer
The history of computer development is often
referred to in reference to the different generations of computing devices.
A generation refers to the state of improvement in the product development
process. This term is also used in the different advancements of new
computer technology. With each new generation, the circuitry has gotten smaller
and more advanced than the previous generation before it. As a result of the
miniaturization, speed, power, and computer memory has proportionally
increased. New discoveries are constantly being developed that affect the way
we live, work and play.
Each generation of computers is characterized by
major technological development that fundamentally changed the way computers
operate, resulting in increasingly smaller, cheaper, more powerful and more
efficient and reliable devices. Read about each generation and the developments
that led to the current devices that we use today.
First Generation - 1940-1956: Vacuum Tubes
The first computers used vacuum
tubes for circuitry and magnetic drums for memory, and were often enormous,
taking up entire rooms. A magnetic drum,also referred to as drum, is a metal
cylinder coated with magnetic iron-oxide material on which data and programs
can be stored. Magnetic drums were once use das a primary storage device but
have since been implemented as auxiliary storage devices.
The tracks on a magnetic drum are assigned to
channels located around the circumference of the drum, forming adjacent
circular bands that wind around the drum. A single drum can have up to 200
tracks. As the drum rotates at a speed of up to 3,000 rpm, the device's
read/write heads deposit magnetized spots on the drum during the write
operation and sense these spots during a read operation. This action is similar
to that of a magnetic tape or disk drive.
They were very expensive to operate and in
addition to using a great deal of electricity, generated a lot of heat, which
was often the cause of malfunctions. First generation computers relied on
machine language to perform operations, and they could only solve one problem
at a time. Machine languages are the only languages understood by computers.
While easily understood by computers, machine languages are almost impossible
for humans to use because they consist entirely of numbers. Computer
Programmers, therefore, use either high level programming
languages or an assembly language programming. An assembly
language contains the same instructions as a machine language, but the
instructions and variables have names instead of being just numbers.
Programs written in high level
programming languages retranslated into assembly language or
machine language by a compiler. Assembly language program retranslated into
machine language by a program called an assembler (assembly language
compiler).
Every CPU has its own unique machine language.
Programs must be rewritten or recompiled, therefore, to run on different types
of computers. Input was based onpunch card and paper tapes, and output was
displayed on printouts.
The UNIVAC and ENIAC computers are examples of
first-generation computing devices. The UNIVAC was the first commercial
computer delivered to a business client, the U.S. Census Bureau in 1951.
Acronym for Electronic Numerical Integrator And
Computer, the world's first operational electronic digital computer, developed
by Army Ordnance to compute World War II ballistic firing tables. The ENIAC,
weighing 30 tons, using 200 kilowatts of electric power and consisting of
18,000 vacuum tubes,1,500 relays, and hundreds of thousands of
resistors,capacitors, and inductors, was completed in 1945. In addition to
ballistics, the ENIAC's field of application included weather prediction,
atomic-energy calculations, cosmic-ray studies, thermal ignition,random-number
studies, wind-tunnel design, and other scientific uses. The ENIAC soon became
obsolete as the need arose for faster computing speeds.
Second Generation - 1956-1963: Transistors
Transistors replaced vacuum tubes
and ushered in the second generation computer. Transistor is a device
composed of semiconductor material that amplifies a signal or opens or closes a
circuit. Invented in 1947 at Bell Labs, transistors have become the key
ingredient of all digital circuits, including computers. Today's latest
microprocessor contains tens of millions of microscopic
transistors.
Prior to the invention of transistors, digital
circuits were composed of vacuum tubes, which had many disadvantages. They were
much larger, required more energy, dissipated more heat, and were more prone to
failures. It's safe to say that without the invention of transistors, computing
as we know it today would not be possible.
The transistor was invented in 1947 but did not
see widespread use in computers until the late 50s. The transistor was far
superior to the vacuum tube,allowing computers to become smaller, faster,
cheaper,more energy-efficient and more reliable than their first-generation
predecessors. Though the transistor still generated a great deal of heat that
subjected the computer to damage, it was a vast improvement over the vacuum
tube. Second-generation computers still relied on punched cards for input and
printouts for output.
Second-generation computers moved from cryptic
binary machine language to symbolic, or assembly, languages,which allowed
programmers to specify instructions in words. High-level programming languages
were also being developed at this time, such as early versions of COBOL and
FORTRAN. These were also the first computers that stored their instructions in
their memory, which moved from a magnetic drum to magnetic core technology.
The first computers of this generation were developed
for the atomic energy industry.
Third Generation - 1964-1971: Integrated Circuits
The development of the integrated
circuit was the hallmark of the third generation of computers. Transistors were
miniaturized and placed on silicon chips, called semiconductors, which
drastically increased the speed and efficiency of computers.
A nonmetallic chemical element in the carbon
family of elements. Silicon - atomic symbol "Si" - is the second most
abundant element in the earth's crust, surpassed only by oxygen. Silicon does
not occur uncombined in nature. Sand and almost all rocks contain silicon
combined with oxygen, forming silica. When silicon combines with other
elements, such as iron, aluminum or potassium, a silicate is formed. Compounds
of silicon also occur in the atmosphere, natural waters,many plants and in the
bodies of some animals.
Silicon is the basic material used to make
computer chips, transistors, silicon diodes and other electronic circuits and
switching devices because its atomic structure makes the element an ideal
semiconductor. Silicon is commonly doped, or mixed,with other elements, such as
boron, phosphorous and arsenic, to alter its conductive properties.
A chip is a small piece of semi conducting
material(usually silicon) on which an integrated circuit is embedded. A typical
chip is less than ¼-square inches and can contain millions of electronic
components(transistors). Computers consist of many chips placed on electronic
boards called printed circuit boards. There are different types of chips. For
example, CPU chips (also called microprocessors) contain an entire processing
unit, whereas memory chips contain blank memory.
Semiconductor is a material that is neither a
good conductor of electricity (like copper) nor a good insulator (like rubber).
The most common semiconductor materials are silicon and germanium. These
materials are then doped to create an excess or lack of electrons.
Computer chips, both for CPU and memory, are
composed of semiconductor materials. Semiconductors make it possible to
miniaturize electronic components, such as transistors. Not only does
miniaturization mean that the components take up less space, it also means that
they are faster and require less energy.
Instead of punched cards and printouts, users interacted
with third generation computers through keyboards and monitors and interfaced
with an operating system, which allowed the device to run many different
applications at one time with a central program that monitored the memory.
Computers for the first time became accessible to a mass audience because they
were smaller and cheaper than their predecessors.
Fourth Generation - 1971-Present:
Microprocessors
The microprocessor brought the fourth generation
of computers, as thousands of integrated circuits we rebuilt onto a single
silicon chip. A silicon chip that contains a CPU. In the world of personal
computers,the terms microprocessor and CPU are used interchangeably. At the
heart of all personal computers and most workstations sits a microprocessor.
Microprocessors also control the logic of almost all digital devices, from
clock radios to fuel-injection systems for automobiles.
Three
basic characteristics differentiate microprocessors:
- Instruction Set: The set of instructions that the microprocessor can execute.
- Bandwidth: The number of bits processed in a single instruction.
- Clock Speed: Given in megahertz (MHz), the clock speed determines how many instructions per second the processor can execute.
In both cases, the higher the value, the more
powerful the CPU. For example, a 32-bit microprocessor that runs at 50MHz is
more powerful than a 16-bitmicroprocessor that runs at 25MHz.
What in the first generation filled an entire
room could now fit in the palm of the hand. The Intel 4004chip, developed in 1971,
located all the components of the computer - from the central processing unit
and memory to input/output controls - on a single chip.
Abbreviation of central processing unit, and
pronounced as separate letters. The CPU is the brains of the computer. Sometimes
referred to simply as the processor or central processor, the CPU is where most
calculations take place. In terms of computing power,the CPU is the most
important element of a computer system.
On large machines, CPUs require one or more
printed circuit boards. On personal computers and small workstations, the CPU
is housed in a single chip called a microprocessor.
Two typical components of a CPU are:
- The arithmetic logic unit (ALU), which performs arithmetic and logical operations.
- The control unit, which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.
In 1981 IBM introduced its first computer for the
home user, and in 1984 Apple introduced the Macintosh. Microprocessors also
moved out of the realm of desktop computers and into many areas of life as more
and more everyday products began to use microprocessors.
As these small computers became more powerful,
they could be linked together to form networks, which eventually led to the
development of the Internet. Fourth generation computers also saw the
development of GUI's, the mouse and handheld devices
Fifth Generation - Present and Beyond: Artificial Intelligence
Fifth generation computing
devices, based on artificial intelligence, are still in development,though
there are some applications, such as voice recognition, that are being used
today.
Artificial Intelligence is the branch of computer
science concerned with making computers behave like humans. The term was coined
in 1956 by John McCarthy at the Massachusetts Institute of Technology.
Artificial intelligence includes:
- Games Playing: programming computers to play games such as chess and checkers
- Expert Systems: programming computers to make decisions in real-life situations (for example, some expert systems help doctors diagnose diseases based on symptoms)
- Natural Language: programming computers to understand natural human languages
- Neural Networks: Systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains
- Robotics: programming computers to see and hear and react to other sensory stimuli
Currently, no computers exhibit full artificial
intelligence (that is, are able to simulate human behavior). The greatest
advances have occurred in the field of games playing. The best computer chess
programs are now capable of beating humans. In May,1997, an IBM super-computer
called Deep Blue defeated world chess champion Gary Kasparov in a chess match.
In the area of robotics, computers are now widely
used in assembly plants, but they are capable only of very limited tasks.
Robots have great difficulty identifying objects based on appearance or feel,
and they still move and handle objects clumsily.
Natural-language processing offers the greatest potential
rewards because it would allow people to interact with computers without
needing any specialized knowledge. You could simply walk up to a computer and
talk to it. Unfortunately, programming computers to understand natural
languages has proved to be more difficult than originally thought. Some
rudimentary translation systems that translate from one human language to
another are in existence, but they are not nearly as good as human translators.
There are also voice recognition systems that can
convert spoken sounds into written words, but they do not understand what they
are writing; they simply take dictation. Even these systems are quite limited
-- you must speak slowly and distinctly.
In the early 1980s, expert systems were believed
to represent the future of artificial intelligence and of computers in general.
To date, however, they have not lived up to expectations. Many expert systems
help human experts in such fields as medicine and engineering, but they are
very expensive to produce and are helpful only in special situations.
Today, the hottest area of artificial
intelligence is neural networks, which are proving successful in an umber of
disciplines such as voice recognition and natural-language processing.
There are several programming languages that are
known as AI languages because they are used almost exclusively for AI
applications. The two most common are LISP and Prolog.
Related Article: Discover
Computer History
Voice Recognition
The field of computer science that deals with
designing computer systems that can recognize spoken words. Note that voice
recognition implies only that the computer can take dictation, not that it
understands what is being said. Comprehending human languages falls under a
different field of computer science called natural language processing. A
number of voice recognition systems are available on the market. The most
powerful can recognize thousands of words. However, they generally require an
extended training session during which the computer system becomes accustomed
to a particular voice and accent. Such systems are said to be speaker
dependent.
Many systems also require that the speaker speak
slowly and distinctly and separate each word with a short pause. These systems
are called discrete speech systems. Recently, great strides have been made in
continuous speech systems -- voice recognition systems that allow you to speak
naturally. There are now several continuous-speech systems available for
personal computers.
Because of their limitations and high cost, voice
recognition systems have traditionally been used only in a few specialized
situations. For example, such systems are useful in instances when the user is
unable to use a keyboard to enter data because his or her hands are occupied or
disabled. Instead of typing commands, the user can simply speak into a headset.
Increasingly, however, as the cost decreases and performance improves, speech
recognition systems are entering the mainstream and are being used as an
alternative to keyboards.
The use of parallel processing and
superconductors is helping to make artificial intelligence a reality. Parallel
processing is the simultaneous use of more than one CPU to execute a program. Ideally,
parallel processing makes a program run faster because there are more engines
(CPUs) running it. In practice, it is often difficult to divide a program in
such a way that separate CPUs can execute different portions without
interfering with each other.
Most computers have just one CPU, but some models
have several. There are even computers with thousands of CPUs. With single-CPU
computers, it is possible to perform parallel processing by connecting the
computers in a network. However, this type of parallel processing requires very
sophisticated software called distributed processing software.
Note that parallel processing differs from
multitasking, in which a single CPU executes several programs at once.
Parallel processing is also called parallel computing.
Quantum computation and molecular and
nano-technology will radically change the face of computers in years to come.
First proposed in the 1970s, quantum computing relies on quantum physics by
taking advantage of certain quantum physics properties of atoms or nuclei that
allow them to work together as quantum bits, or qubits, to be the computer's
processor and memory. By interacting with each other while being isolated from
the external environment,qubits can perform certain calculations exponentially
faster than conventional computers.
Qubits do not rely on the traditional binary
nature of computing. While traditional computers encode information into bits
using binary numbers, either a 0or 1, and can only do calculations on one set
of numbers at once, quantum computers encode information as a series of
quantum-mechanical states such as spin directions of electrons or polarization
orientations of a photon that might represent a 1 or a 0, might represent a
combination of the two or might represent a number expressing that the state of
the qubit is somewhere between 1 and 0, or a superposition of many different
numbers at once. A quantum computer can doan arbitrary reversible classical
computation on all the numbers simultaneously, which a binary system cannot do,
and also has some ability to produce interference between various different
numbers. By doing a computation on many different numbers at once,then
interfering the results to get a single answer, a quantum computer has the
potential to be much more powerful than a classical computer of the same
size.In using only a single processing unit, a quantum computer can naturally
perform myriad operations in parallel.
Quantum computing is not well suited for tasks
such as word processing and email, but it is ideal for tasks such as
cryptography and modeling and indexing very large databases.
Nanotechnology is a field of science whose goal
is to control individual atoms and molecules to create computer chips and other
devices that are thousands of times smaller than current technologies permit.
Current manufacturing processes use lithography to imprint circuits on
semiconductor materials. While lithography has improved dramatically over the
last two decades -- to the point where some manufacturing plants can produce
circuits smaller than one micron(1,000 nanometers) -- it still deals with
aggregates of millions of atoms. It is widely believed that lithography is
quickly approaching its physical limits. To continue reducing the size of
semiconductors, new technologies that juggle individual atoms will be
necessary. This is the realm of nanotechnology.
Although research in this field dates back to
Richard P. Feynman's classic talk in 1959, the term nanotechnology was first
coined by K. Eric Drexler in1986 in the book Engines of Creation.
In the popular press, the term nanotechnology is
sometimes used to refer to any sub-micron process,including lithography.
Because of this, many scientists are beginning to use the term molecular
nanotechnology when talking about true nanotechnology at the molecular level.
The goal of fifth-generation computing is to
develop devices that respond to natural language input and are capable of
learning and self-organization.
Here natural language means a human language. For
example, English, French, and Chinese are natural languages. Computer
languages, such as FORTRAN and C,are not.
Probably the single most challenging problem in
computer science is to develop computers that can understand natural languages.
So far, the complete solution to this problem has proved elusive, although
great deal of progress has been made. Fourth-generation languages are the
programming languages closest to natural languages.
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