Chapter 1 Introduction to a Typical PC 5
Computer Data Codes
Data can be almost anything. It can be
numbers, text, pictures, and sounds. Computer
data and functions are expressed in a variety of
ways. They can be expressed as voltage levels,
numeric systems such as binary and hexadecimal,
and symbolic codes such as ASCII. Although
computer data and commands can be expressed
in many different forms and still have the same
meaning, the form selected should be the one
that is easiest to grasp for the given material. For
example, it is much easier to express memory
locations as hexadecimal values rather than
binary values, although the memory location
could be expressed in either value. The computer
technician must be very familiar with each of
these forms of data expression.
Binary Number Code
The binary number system consists
of entirely ones and zeros. It is the perfect
numbering system to represent digital electronic
voltages are pulsed through the system. These
pulses of high and low voltages create what is
called a digital signal. Many things can be done
with these electrical energy pulses. Data can be
displayed on a computer monitor or can be stored
in memory chips or storage media such as a hard
drive, flash drive, or compact disc (CD). When
written to a hard drive, the electrical pulses are
converted to magnetic patterns on the surface of
the disk.
Data in a computer system is represented
as ones and zeros. The pattern of ones and
zeros is known as the binary system. You will
be introduced to the binary system later in this
chapter. Some digital patterns represent words,
pictures, and sounds. Other digital patterns
represent commands such as
load
file,
find
file, and
save
file. Remember, the computer does not contain
any intelligence. It simply manipulates, stores, and
displays data.
Union Tools, Inc.I
Goodheart-Willcox Publisher
Figure 1-4.
Sound, pictures, and
text are all forms of
data. Each can be
represented by a code
consisting of ones
and zeros, the binary
number system.
U i T l
0 1 1 1 1 1 0 0 0 0
+ 5 volts
0 volts
Sound
Picture
Text