created: 06/25/96; 2^{nd} edition: 05/13/01;
little bitty changes: 09/01/01; audio 12/06/03; slightly revised: 05/17/15

Computers represent data and instructions with patterns of bits. You must become familiar with bit patterns! This chapter will help you. It discusses the fundamentals of bit patterns.

**Chapter Topics:**

- Patterns of bits.
- The number of patterns that can be formed for N bits.
- How to systematically list all the patterns for N bits.
- Multiplying powers of two.
- Bytes, kilobytes, megabytes, and gigabytes.
- Names for four-bit patterns.
- Hexadecimal names for bit patterns.
- Octal names for bit patterns.

In most computer documentation,
8 contiguous bits are called a **byte**.
A bit holds a zero or a one,
possibly representing the on/off condition of
a switch.

How many patterns can be formed with a single bit? (Hint: click on the switch!)