INTRODUCTION TO MICROCOMPUTERS
Chapter 1
Introduction
to
Microcomputers
This
chapter
introduces
the
basic concepts of microcomputer
systems
to
users with
little or no previous knowledge of computer systems.
What
is
aMicrocomputer?
Amicrocomputer is
an
electronic machine which processes information rapidly. A
microcomputercannot
think
for itself;
it
canonlydoexactly
what
it
is
instructed
to
do
by computer programs.
The term microcomputer
system
generally refers
to
anumber of separate elements
which work together
to
achieve arequired result. Theseelements can be
thought
ofin
two main groups;
the
electronic machines, called hardware,
and
the
computer
programs, called software.
Hardware
Atypical microcomputer
system
consists
of:
• A keyboard
• A visual display
unit
• A processor
•
An
internal memory
•
An
external storage device
• A
printer
The keyboard lets you communicate with
the
processor.
The visual display
unit
(VDU) lets you see
what
you have told
the
system
to
do,
and
what
messages
the
system
has
sent
to
you. These messages
may
include
any
other
information previously stored in
the
computer system.
The processor,
as
the
name suggests, processes your information
as
instructed
by
a
computer program. The processor includes amicroprocessor
that
executes programs
by
performing arithmetical
and
logical operations on information stored in
the
computer's memory.
This
memory
is mainly 'volatile': volatile memory, usually called random access
memory(RAM), canbemodified
by
aprogramduringprocessing,
but
when
the
system
is
turned
off
the
contentsofthismemoryarelost.
Each
time
the
system
is
turned
on
the
program
and
the
information
must
be reloaded from a'non-volatile' storage device.
Theinternalmemoryalsoincludesread-onlymemory(ROM) whichis non- volatile;
the
contents of ROM are
not
lost when
the
system
is
turned
off. This memory has special
uses within
the
system.
1.1
