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1.3 Generation of computers
Fourth Generation (1971-Present)
After the inte.g.rated circuits, the only place to go was down - in
size, that is. Large-scale inte.g.ration (LSI) could fit hundreds of components
onto one chip. By the 1980's, very large scale inte.g.ration (VLSI) squeezed
hundreds of thousands of components onto a chip. Ultra-large scale
inte.g.ration (ULSI) increased that number into the millions. The ability to
fit so much onto an area about half the size of a U.S. dime helped diminish the
size and price of computers. It also increased their power, efficiency and
reliability. The Intel 4004 chip, developed in 1971, took the inte.g.rated
circuit one step further by locating all the components of a computer (central
processing unit, memory, and input and output controls) on a minuscule chip.
Whereas previously the inte.g.rated circuit had had to be manufactured to fit a
special purpose, now one microprocessor could be manufactured and then
programmed to meet any number of demands. Soon everyday household items such as
microwave ovens, television sets and automobiles with electronic fuel injection
incorporated microprocessors.
Such condensed power allowed everyday people to harness a computer's
power. They were no longer developed exclusively for large business or
government contracts. By the mid-1970's, computer manufacturers sought to bring
computers to general consumers. These minicomputers came complete with
user-friendly software packages that offered even non-technical users an array
of applications, most popularly word processing and spreadsheet programs.
Pioneers in this field were Commodore, Radio Shack and Apple Computers. In the
early 1980's, arcade video games such as Pac Man and home video game systems
such as the Atari 2600 ignited consumer interest for more sophisticated,
programmable home computers.
In 1981, IBM introduced its personal computer (PC) for use in the home,
office and schools. The 1980's saw an expansion in computer use in all three
arenas as clones of the IBM PC made the personal computer even more affordable.
The number of personal computers in use more than doubled from 2 million in
1981 to 5.5 million in 1982. Ten years later, 65 million PCs were being used.
Computers continued their trend toward a smaller size, working their way down
from desktop to laptop computers (which could fit inside a briefcase) to
palmtop (able to fit inside a breast pocket). In direct competition with IBM's
PC was Apple's Macintosh line, introduced in 1984. Notable for its user-friendly
design, the Macintosh offered an operating system that allowed users to move
screen icons instead of typing instructions. Users controlled the screen cursor
using a mouse, a device that mimicked the movement of one's hand on the
computer screen.
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As computers became more widespread in the workplace, new ways to
harness their potential developed. As smaller computers became more powerful,
they could be linked together, or networked, to share memory space, software,
information and communicate with each other. As opposed to a mainframe
computer, which was one powerful computer that shared time with many terminals
for many applications, networked computers allowed individual computers to form
electronic co-ops. Using either direct wiring, called a Local Area Network
(LAN), or telephone lines, these networks could reach enormous proportions. A
global web of computer circuitry, the Internet, for example, links computers
worldwide into a single network of information. During the 1992 U.S.
presidential election, vice-presidential candidate Al Gore promised to make the
development of this so-called "information superhighway" an
administrative priority. Though the possibilities envisioned by Gore and others
for such a large network are often years (if not decades) away from
realization, the most popular use today for computer networks such as the
Internet is electronic mail, or E-mail, which allows users to type in a
computer address and send messages through networked terminals across the
office or across the world.
Fifth Generation (Present and Beyond)
Defining the fifth generation of computers is somewhat difficult
because the field is in its infancy. The most famous example of a fifth
generation computer is the fictional HAL9000 from Arthur C. Clarke's novel,
2001: A Space Odyssey. HAL performed all of the functions currently
envisioned for real-life fifth generation computers. With artificial
intelligence, HAL could reason well enough to hold conversations with its human
operators, use visual input, and learn from its own experiences.
(Unfortunately, HAL was a little too human and had a psychotic breakdown,
commandeering a spaceship and killing most humans on board.)
Though the wayward HAL9000 may be far from the reach of real-life
computer designers, many of its functions are not. Using recent engineering
advances, computers are able to accept spoken word instructions (voice
recognition) and imitate human reasoning. The ability to translate a foreign
language is also moderately possible with fifth generation computers. This feat
seemed a simple objective at first, but appeared much more difficult when
programmers realized that human understanding relies as much on context and
meaning as it does on the simple translation of words.
Many advances in the science
of computer design and technology are coming together to enable the creation of
fifth-generation computers. Two such engineering advances are parallel
processing, which replaces von Neumann's single central processing unit design
with a system harnessing the power of many CPUs to work as one. Another advance
is superconductor technology, which allows the flow of electricity with little
or no resistance, greatly improving the speed of information flow. Computers
today have some attributes of fifth generation computers. For example, expert
systems assist doctors in making diagnoses by applying the problem-solving
steps a doctor might use in assessing a patient's needs. It will take several
more years of development before expert systems are in widespread use.
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