1. 1 Bits, Bytes, and Binary Numbers Bits and bytes are small pieces of computerized data that communicate commands to a computer’s CPU: A bit is either a 1 or a 0 (binary digits). A byte contains eight bits. Each letter in the English language is represented by one byte. 1

2. 2 What is Hardware? “Hardware” is any part of a computer that you can touch. There are two kinds of hardware: 1. internal 2. external

3. 3 Internal Hardware Power enters computer through power cord. Electricity travels through motherboard, where all components are attached. Electricity travels to the central processing unit (CPU), also called the microprocessor.

4. 44 How Does My Computer Work? The “brain” of a computer is the central processing unit (CPU). When the CPU receives and carries out an instruction, it has completed one cycle. Computer’s speed = number of cycles completed in one second Cycles are measured in: Megahertz (MHz) = millions of cycles per second Gigahertz (GHz) = billions of cycles per second

5. 5 How CPUs Work The CPU is the brain of the computer. The CPU performs four tasks: 1. fetch 2. decode 3. execute 4. store

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7. 7 Internal Hardware (continued) The cache holds instructions that are accessed frequently. There are two kinds of cache: 1. internal or L1 – first place that the CPU looks 2. external or L2 – second place that the CPU looks

8. 8 Expansion slots can hold expansion cards such as a sound card or modem. Bus is a series of conductor wires that transport data between internal hardware. –Wider bus widths result in more data being transported at faster speeds.

9. 9 Internal Hardware (continued) Drive bays hold disk drives such as hard drive and DVD drive. Memory chips are also attached to the motherboard. –R–ROM – Read Only Memory also called the system BIOS houses information such as instructions for start-up store data even when the computer is turned off –R–RAM – Random Access Memory temporary works when you start up and use computer software only stores information when the computer is on

10. 10 Computer Storage The type of storage device used depends on –the type of information being stored –how much information being stored Examples of storage options include –hard drive –floppy disk –CD-R or CD-RW –DVD+/-R or DVD+/-RW –online storage –external hard drive –USB Flash drive

11. 11 Work Go to our site and do: – Read Computer Files note – File Naming Worksheet – File Address Worksheet 11