Computers Are Your Future Twelfth Edition Chapter 2: Inside the System Unit Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 1

How Computers Represent Data Computers use the Binary Number SystemBinary Number System Binary numbers - Only 0s and 1s Bit (Binary Digit) o Smallest piece of data a computer can work with o Either “on” = 1 or “off” = 0 o Eight bits—byte—a single unit of storage Characters o Letters, numbers, and symbols—converted into numbers the computer understands Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 2

How Computers Represent Data Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 3

How Computers Represent Data Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall4 Modem’s data transfer rate is in bits per second (bps) Ex. — gigabits per second (Gbps)

System Unit System Unit Case that contains the major hardware components of a computer Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 5

o Motherboard o CPU o Power supply o Cooling fan o RAM o Internal speaker o Drive bays o Expansion slots- integrated circuits fit into System unit main components Inside the System Unit Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 6

Inside the System Unit Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 7

8 Inside the System Unit

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 9 What’s on the Motherboard? CPU Input/Output Buses System Clock

Motherboard o Circuit board that contains the electrical circuitry for the computer What’s on the Motherboard? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 10

What’s on the Motherboard? Central processing unit (CPU) o Integrated circuit chip that processes electronic signals o Also called microprocessor or processor o Brains of the Computer o Interprets and carries out instructions by processing data and controlling the computer’s components Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 11

What’s on the Motherboard? 2 parts of the CPU o Control unit Retrieves instructions from memory and runs them o Arithmetic logic unit (ALU) Performs arithmetic and logical operations Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 12

What’s on the Motherboard? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 13

Data Bus o Group of parallel wires that connect the CPU’s internal components o Width measured in bits What’s on the Motherboard? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 14

What’s on the Motherboard? System clock o Electronic circuit that controls computer speed o Clock speed—measurement of the electrical pulses generated by the system clock, usually measured in gigahertz (GHz) Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 15

Memory o Chips on the motherboard or within the CPU that retain instructions and data Random access memory (RAM)RAM o Temporarily stores data and instructions for the CPU o Volatile—contents erased after computer is shut off What’s on the Motherboard? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 16

What’s on the Motherboard? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 17 Virtual memory o Section of the hard drive set aside to use when RAM gets full

What’s on the Outside of the Box? Outside a system unit o Port—electronic pathway used to send and retrieve data from the computer Example: USB port o USB (universal serial bus) ports o Connects up to 127 peripheral devices Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 18

What’s on the Outside of the Box? Legacy technology o Older technology that is being phased out Examples: Serial ports Parallel ports Floppy Disks Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 19