Figure 15-1.-A personal computer system.
valve that controls the flow of steam to a turbine
generator or a temperature setting to control the
ovens in the ships galley for baking. Analog
computers are also used for controlling processes.
To do so, they must convert analog data to digital
form, process it, and then convert the digital
results back to analog form.
Digital computers can process data more
accurately than analog computers, but analog
computers can process data faster than digital
functions of both analog and digital computers,
and are known as hybrid computers.
As a PN, you will probably never work with
analog computers since they are not designed for
data processing applications.
Digital computers perform arithmetic and
logic functions on separate discrete data, like
numbers, or combinations of discrete data, such
as name, rate, and division. This makes them
different from analog computers, which operate
on continuous data, like measuring temperature
changes. As a rule, digital computers are used for
business and scientific data processing. They may
be either special or general-purpose.
WORD PROCESSING SOFTWARE
You can use word processing software for any
function that involves text, such as letters,
memorandums, forms, and reports. You could be
using microcomputers (fig. 15-1) to perform any of
At a minimum, computers are used for
creating, editing, storing, retrieving, and printing
text. Under the word processing software control,
you generally enter the text on the keyboard and
it is displayed on a screen (fig. 15-2). Then the
material may be changed (edited), stored on a
disk or tape, or printed on a printer.
When you use a computer for a word
processing job, you can change material by
adding or deleting words, characters, lines,
sentences, or paragraphs. You can rearrange
text by moving a paragraph or block of
information to another place in the same
Figure 15-2.-Word Processing example.