DOMAIN 1: IT Concepts & Terminology

Bit

Smallest unit of data; a single 0 or 1

Byte

A unit of data made up of 8 bits

Nibble

4 bits, or half a byte

Binary

Base 2 number system using only 0 and 1

Decimal

Base 10 number system, the standard human counting system

Hexadecimal

Base 16 number system using digits 0-9 and letters A-F

ASCII

Character-encoding standard mapping letters/numbers/symbols to binary values

Integer

Data type for whole numbers with no decimal point

Float

Data type for numbers that include decimal points

String

Data type representing text or characters

Boolean

Data type with only two possible values: true or false

Character (char)

Data type representing a single letter, number, or symbol

Input

Data entering a computer system, e.g. from keyboard or mouse

Processing

The CPU manipulating and calculating data

Output

The result presented to the user, e.g. on a monitor or printer

Storage

Where data is saved, either short-term (RAM) or long-term (HDD/SSD)

IPOS cycle

The order Input, Processing, Output, Storage

Kilobyte (KB)

A unit of storage equal to about 1,000 bytes

Megabyte (MB)

A unit of storage equal to about 1,000 kilobytes

Gigabyte (GB)

A unit of storage equal to about 1,000 megabytes

Terabyte (TB)

A unit of storage equal to about 1,000 gigabytes

Network speed units

Measured in bits per second (bps/Mbps/Gbps), not bytes

Hertz (Hz)

Unit measuring cycles per second, used for CPU clock speed

Troubleshooting Step 1

Identify the problem

Troubleshooting Step 2

Establish a theory of probable cause

Troubleshooting Step 3

Test the theory to determine the cause

Troubleshooting Step 4

Establish a plan of action to resolve the problem

Troubleshooting Step 5

Implement the solution

Troubleshooting Step 6

Verify full system functionality

Troubleshooting Step 7

Document findings, actions, and outcomes