UPGRADING REPAIRING PCs

Understanding Bits, Nibbles, and Bytes 3
Figure 1.2 Ports on the rear of a typical ATX motherboard.
Understanding Bits, Nibbles, and
Bytes
The foundation of all memory and disk size calculations is the byte.
When storing plain-text data, a byte equals one character.
Data can also be stored or transmitted in portions of a byte. A bit
equals 1/8 of a byte, or, in other words, a byte equals eight bits. A
nibble equals 1/2 of a byte, or four bits. Thus, two nibbles equal one
byte. Keep the difference between bits and bytes in mind as you
review the table of standard capacity abbreviations and meanings.
Standard Capacity Abbreviations and Meanings
Use the following table to translate megabytes, gigabytes, and the
other abbreviations used to refer to memory and disk space into
their decimal or binary values.
Unfortunately, some parts of the computer industry use the decimal
values, while others use the binary values. Typically, hard disk
and other drive manufacturers rate their products in decimal
megabytes or gigabytes. On the other hand, the ROM BIOS on
most (but not all) systems and the MS-DOS and Windows FDISK
programs use binary megabytes or gigabytes, thus creating an
apparent discrepancy in disk capacity. RAM is virtually always calculated
using binary values.