Section I. THE MAJOR COMPONENTS
The computer is actually a system of interrelated components. These
components, known collectively as hardware, are the machines that make up a
functioning computer. Although, it is not necessary to have a detailed knowledge of
computer technology to perform data processing activities, knowing about the
components and its functions will give you a better appreciation of a computer's
capabilities and limitations.
hardware: the physical apparatus of a computer system.
DIGITAL VS ANALOG COMPUTERS
a. Digital computers are by far the most widely used type of computer. Most
modern electronic computers are digital, and, for the most part, this book focuses on
this type of computer. But, there are, in fact, two ways in which data may be sent over
communications channels. These two methods correspond to the two types of
computers: digital and analog. A digital computer operates directly on numbers
expressed as digits and responds to the discrete "on" and "off" states of electronic
circuitry. These 'on" and "off" states can be represented by 1's and 0's, called binary
digits, which can be counted. Digital computers operate by counting, but vary in
precision with those used for scientific applications achieving accuracy to the hundredth
or even thousandth place. Computers used for business applications are generally
accurate to only a few decimal places.
digital computer: computer capable of performing calculations by counting is
and Os; data is represented as discrete digital "on-off' states.
Figure 2-1. Data may be sent over communications lines as "on-off" (digital)
or continuous (analog) signals.