Page 79 - DCAP210_INTRODUCTION__TO_MICROPROCESSORS

Unit 5: Microcomputer System

multimedia computer system are directly connected to a device controller called an audio card Notes
which in turn is connected to the rest of the system.

Hand-held scanners are commonly seen in big stores to scan codes and price
information for each of the items. They are also termed the barcode readers.

Input and output devices are similar in operation but perform opposite functions. It is through
the use of these devices that the computer is able to communicate with the outside world.

Search about the details of I/O devices.

History of Microcomputer

he term “microcomputer” came into popular use after the introduction of the minicomputer,
although Isaac Asimov used the term microcomputer in his short story “The Dying Night”
Tas early as 1956 (published in The Magazine of Fantasy and Science Fiction in July that
year). Most notably, the microcomputer replaced the many separate components that made up
the minicomputer’s CPU with a single integrated microprocessor chip.
The earliest models often sold as kits to be assembled by the user, and came with as little as 256
bytes of RAM, and no input/output devices other than indicator lights and switches. However,
as microprocessor design advanced rapidly and semiconductor memory became less expensive
from the early-to-mid-1970s onwards, microcomputers in turn grew faster and cheaper. This
resulted in an explosion in their popularity during the late 1970s and early 1980s.
The increasing availability and power of desktop computers for personal use attracted the
attention of more software developers. As time went on and the industry matured, the market
for personal (micro) computers standardized around IBM PC compatibles running MS-DOS
(and later Windows).
Modern desktop computers, video game consoles, laptop computers, tablet PCs, and many
types of hand-held devices, including mobile phones and pocket calculators, as well as
industrial embedded systems, may all be considered examples of microcomputers according
to the definition given above.
Colloquial use of the term

Everyday use of the expression “microcomputer” (and in particular the “micro” abbreviation) has
declined significantly from the mid-1980s onwards, and is no longer commonplace. It is most
commonly associated with the first wave of all-in-one 8-bit home computers and small business
microcomputers (such as the Apple II, Commodore 64, BBC Micro, and TRS 80). Although—or
perhaps because—an increasingly diverse range of modern microprocessor-based devices fit the
definition of “microcomputer,” they are no longer referred to as such in everyday speech.
In common usage, “microcomputer” has been largely supplanted by the description “personal
computer” or “PC,” which describes that it has been designed to be used by one person at a
time. IBM first promoted the term “personal computer” to differentiate themselves from other
microcomputers, often called “home computers” and also IBM’s own mainframes and
minicomputers. Unfortunately for IBM, the microcomputer itself was widely imitated, as
well as the term. The component parts were commonly available to manufacturers and the
BIOS was reverse engineered through clean room design techniques. IBM PC compatible
Contd...

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