|
In the
mid-1940s, early computers were the size of houses
and as expensive as battleships, but they had none
of the computational power or ease of use that are
common in modern PCs. The miniaturization of
electronic circuitry and the invention of integrated
circuits and microprocessors enabled computer makers
to combine the essential elements of a computer onto
tiny silicon computer chips, thereby increasing
computer performance and decreasing cost. The first
microprocessor, the Intel 4004, created in 1971 by
Intel Corporation, was originally designed to be the
computing and logical processor of calculators and
watches. From its simple design modern
microprocessors evolved
Microsoft ® Encarta ® Reference Library 2005. ©
1993-2004 Microsoft Corporation. All rights
reserved.
The Altair 8800, developed in 1975 by Micro
Instrumentation Telemetry Systems (MITS), is
considered to be the first PC. The Altair was built
from a kit and programmed by using switches.
Information from the computer was displayed by
light-emitting diodes on the front panel of the
machine. The Altair appeared on the cover of Popular
Electronics magazine in 1975 and inspired many
computer enthusiasts who would later establish
companies to produce computer hardware and software.
American computer designers Steven Jobs and Stephen
Wozniak created the Apple II in 1977. The Apple II
was one of the first PCs to incorporate a color
video display and a keyboard that made the computer
easy to use. Jobs and Wozniak incorporated Apple
Computer, Inc., the same year.
Microsoft ® Encarta ® Reference Library 2005. ©
1993-2004 Microsoft Corporation. All rights
reserved.
In 1981 International Business Machines Corporation
(IBM) introduced the IBM PC. It was designed with an
open architecture that enabled other computer
manufacturers to create similar machines, or clones,
that could also run software designed for the IBM
PC. The design of the IBM PC and its clones soon
became the PC standard, and an operating system
developed by Microsoft Corporation became the
dominant software running PCs.
A graphical user interface (GUI)—a visually
appealing way to represent computer commands and
data on the screen—was first developed in 1983 when
Apple introduced the Lisa, but the new user
interface did not gain widespread notice until 1984
with the introduction of the Apple Macintosh. The
Macintosh GUI combined icons (pictures that
represent files or programs) with windows (boxes
that each contain an open file or program). A
pointing device known as a mouse controlled
information on the screen. Inspired by earlier work
of computer scientists at Xerox Corporation, the
Macintosh user interface made computers easy and fun
to use and eliminated the need to type in complex
commands (see User Interface). Today, software
available for IBM PCs and clones, as well as most
other popular computer platforms, also feature a
GUI.
Since the early 1970s, computing power has doubled
about every 18 months due to the creation of faster
microprocessors, the incorporation of multiple
microprocessor designs, and the development of new
storage technologies. Ongoing research is focused on
creating computers that use light and biological
molecules instead of—or in combination
with—conventional electronic computer circuitry.
These technological advances, coupled with new
methods for interconnecting computers, such as the
proposed Internet2, an advanced Internet under
development by universities, industry, and the
government, promise to make PCs even more powerful
and useful.
Microsoft ® Encarta ® Reference Library 2005
|
صفحه
اصلی 