PC Hardware A Beginner’s Guide

(^28) PC Hardware: A Beginner’s Guide
what is called abyte. A byte can store smaller integer numbers or a single character. The
eight bits of a byte can create 255 different values in the binary number system.
So, what is the binary number system, that is, beyond its one and zero values? The
binary number system is a base-two number system and represents values as exponential
values of two. Compare this to decimal, which is a base-ten number system. Perhaps the
best way to explain binary to you is to refresh your knowledge of decimal.
Decimal numbers, such as 101, are really a combination of individual values, each of
which is expressed as a power of ten. In the case of the number 101, it really means 1 plus
no 10s plus one 100. Everyone knows that, right? However, technically speaking, 101
really represents 1 times 10 to the zero power plus 0 times 10 to the first power plus 1
times 10 to the second power:
(1 10^2 ) + (0 10^1 ) + (1 10^0 ) = 101
Likewise, the number 221 represents
(2 10^2 ) + (2 10^1 ) + (1 10^0 ) = 221
Decimal values have ten numerals (0 to 9) to express how many of a particular power
of ten is included in a number. The worddecimalis derived from the word ten.
The binary number system works just like the decimal system with two exceptions:
each place in a binary number represents a power of two, and the binary system has only
two numerals (0 and 1) it can use to express how many of a particular power of two is
included in a value. Other than that, the binary system works just like the decimal.
Figure 2-2. The binary number system and the transistor each have two values or states