1 of 42

Your Interactive Guide to the Digital World

Discovering � Computers 2012

2 of 42

Objectives Overview

See Page 209

for Detailed Objectives

Discovering Computers 2012: Chapter 4

2

Differentiate among various styles of system units on desktop computers, notebook computers, and mobile devices

Identify chips, adapter cards, and other components of a motherboard

Describe the control unit and arithmetic logic unit components of a processor, and explain the four steps in a machine cycle

Identify characteristics of various personal computer processors on the market today, and describe the ways processors are cooled

Define a bit and describe how a series of bits represents data

Explain how program instructions transfer in and out of memory

3 of 42

Objectives Overview

See Page 209

for Detailed Objectives

Discovering Computers 2012: Chapter 4

3

Differentiate among the various types of memory

Describe the purpose and types of expansion slots and adapter cards, and differentiate among slots for various removable flash memory devices

Differentiate between a port and a connector, and explain the differences among a USB port, FireWire port, Bluetooth port, SCSI port, eSATA port, IrDA port, serial port, and MIDI port

Describe the types of buses in a computer

Explain the purpose of a power supply and describe how it keeps cool

Understand how to clean a system unit on a computer or mobile device

4 of 42

The System Unit

  • The system unit is a case that contains electronic components of the computer used to process data

Page 210

Figure 4-1

Discovering Computers 2012: Chapter 4

4

5 of 42

The System Unit

  • The inside of the system unit on a desktop personal computer includes:

Page 211

Figure 4-2

Discovering Computers 2012: Chapter 4

5

Drive bay(s)

Power supply

Sound card

Video card

Processor

Memory

6 of 42

The System Unit

  • The motherboard is the main circuit board of the system unit
    • A computer chip contains integrated circuits

Page 212

Figure 4-3

Discovering Computers 2012: Chapter 4

6

7 of 42

Processor

  • The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer
    • Contain a control unit and an arithmetic logic unit (ALU)

Page 213

Discovering Computers 2012: Chapter 4

7

Multi-core processor

Dual-core processor

Quad-core processor

8 of 42

Processor

Page 213

Figure 4-4

Discovering Computers 2012: Chapter 4

8

9 of 42

Processor

  • The control unit is the component of the processor that directs and coordinates most of the operations in the computer
  • The arithmetic and logic unit (ALU) performs arithmetic, comparison, and other operations

Page 214

Discovering Computers 2012: Chapter 4

9

10 of 42

Processor

Page 216

Discovering Computers 2012: Chapter 4

10

The processor contains registers, that temporarily hold data and instructions

The system clock controls the timing of all computer operations

    • The pace of the system clock is called the clock speed, and is measured in gigahertz (GHz)

11 of 42

Processor

  • The leading manufacturers of personal computer processor chips are Intel and AMD

Pages 216 – 217

Figure 4-7

Discovering Computers 2012: Chapter 4

11

12 of 42

Processor

  • A processor chip generates heat that could cause the chip to burn up
  • Require additional cooling
    • Heat sinks
    • Liquid cooling technology

Pages 219 - 220

Figures 4-9 – 4-10

Discovering Computers 2012: Chapter 4

12

13 of 42

Processor

  • Parallel processing uses multiple processors simultaneously to execute a single program or task
    • Massively parallel processing involves hundreds or thousands of processors

Page 220

Figure 4-11

Discovering Computers 2012: Chapter 4

13

14 of 42

Data Representation

Page 221

Discovering Computers 2012: Chapter 4

14

Analog signals are continuous and vary in strength and quality

Digital signals are in one of two states: on or off

    • Most computers are digital
    • The binary system uses two unique digits (0 and 1)
      • Bits and bytes(8 bits)

15 of 42

Data Representation

A computer circuit represents the 0 or the 1 electronically by the presence or absence of an electrical charge

Eight bits grouped together as a unit are called a byte. A byte represents a single character in the computer

Page 221

Figures 4-12 – 4-13

Discovering Computers 2012: Chapter 4

15

16 of 42

Data Representation

  • ASCII (American Standard Code for Information Interchange) is the most widely used coding scheme to represent data

Page 221

Figure 4-14

Discovering Computers 2012: Chapter 4

16

17 of 42

Data Representation

Page 222

Figure 4-15

Discovering Computers 2012: Chapter 4

17

18 of 42

Memory

  • Memory consists of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data
  • Stores three basic categories of items:

Page 223

Discovering Computers 2012: Chapter 4

18

The operating system and other system software

Application programs

Data being processed and the resulting information

19 of 42

Memory

  • Each location in memory has an address
  • Memory size is measured in kilobytes (KB or K), megabytes (MB), gigabytes (GB), or terabytes (TB)

Page 223

Figure 4-17

Discovering Computers 2012: Chapter 4

19

20 of 42

Memory

  • The system unit contains two types of memory:

Pages 223 - 224

Discovering Computers 2012: Chapter 4

20

Volatile memory

Loses its contents when power is turned off

Example includes RAM

Nonvolatile memory

Does not lose contents when power is removed

Examples include ROM, flash memory, and CMOS

21 of 42

Memory

Page 224

Figure 4-18

Discovering Computers 2012: Chapter 4

21

22 of 42

Memory

  • Three basic types of RAM chips exist:

Page 225

Figure 4-19

Discovering Computers 2012: Chapter 4

22

Dynamic RAM (DRAM)

Static RAM (SRAM)

Magnetoresistive RAM (MRAM)

23 of 42

Memory

  • RAM chips usually reside on a memory module and are inserted into memory slots

Page 225

Figure 4-20

Discovering Computers 2012: Chapter 4

23

24 of 42

Memory

  • The amount of RAM necessary in a computer often depends on the types of software you plan to use

Page 226

Figure 4-21

Discovering Computers 2012: Chapter 4

24

25 of 42

Memory

Page 228

Discovering Computers 2012: Chapter 4

25

Read-only memory (ROM) refers to memory chips storing permanent data and instructions

    • Firmware

A PROM (programmable read-only memory) chip is a blank ROM chip that can be written to permanently

    • EEPROM can be erased

26 of 42

Memory

  • Flash memory can be erased electronically and rewritten
    • CMOS technology provides high speeds and consumes little power

Pages 228 – 229

Figure 4-23

Discovering Computers 2012: Chapter 4

26

27 of 42

Memory

  • Access time is the amount of time it takes the processor to read from memory
    • Measured in nanoseconds

Page 229

Figures 4-24 – 4-25

Discovering Computers 2012: Chapter 4

27

28 of 42

Ports and Connectors

Page 232

Discovering Computers 2012: Chapter 4

28

A port is the point at which a peripheral attaches to or communicates with a system unit (sometimes referred to as a jack)

A connector joins a cable to a port

29 of 42

Ports and Connectors

Page 232

Figure 4-29

Discovering Computers 2012: Chapter 4

29

30 of 42

Ports and Connectors

  • On a notebook computer, the ports are on the back, front, and/or sides

Pages 232 - 233

Figure 4-30

Discovering Computers 2012: Chapter 4

30

31 of 42

Ports and Connectors

Page 233

Figure 4-31

Discovering Computers 2012: Chapter 4

31

32 of 42

Ports and Connectors

  • A USB port can connect up to 127 different peripherals together with a single connector
    • You can attach multiple peripherals using a single USB port with a USB hub

Page 234

Figure 4-32

Discovering Computers 2012: Chapter 4

32

33 of 42

Ports and Connectors

  • Other types of ports include:

Pages 234 - 236

Discovering Computers 2012: Chapter 4

33

Firewire port

Bluetooth port

SCSI port

eSATA port

IrDA port

Serial port

MIDI port

34 of 42

Ports and Connectors

A Bluetooth wireless port adapter converts a USB port into a Bluetooth port

A smart phone might communicate with a notebook computer using an IrDA port

Page 235

Figures 4-33 – 4-34

Discovering Computers 2012: Chapter 4

34

35 of 42

Ports and Connectors

  • A port replicator is an external device that provides connections to peripherals through ports built into the device
  • A docking station is an external device that attaches to a mobile computer or device

Page 236

Figure 4-35

Discovering Computers 2012: Chapter 4

35

36 of 42

Buses

  • A bus allows the various devices both inside and attached to the system unit to communicate with each other
    • Data bus
    • Address bus
  • Word size is the number of bits the processor can interpret and execute at a given time

Page 237

Figure 4-36

Discovering Computers 2012: Chapter 4

36

37 of 42

Buses

  • Expansion slots connect to expansion buses
  • Common types of expansion buses include:

Page 238

Discovering Computers 2012: Chapter 4

37

PCI bus

PCI Express bus

Accelerated Graphics Port

USB and FireWire bus

PC Card bus

38 of 42

Power Supply

Page 239

Discovering Computers 2012: Chapter 4

38

The power supply converts the wall outlet AC power into DC power

Some external peripherals have an AC adapter, which is an external power supply

39 of 42

Putting It All Together

Page 239

Figure 4-38

Discovering Computers 2012: Chapter 4

39

Home

Intel Core i5 or �Intel Core 2 i3 or �AMD Athlon II or�AMD Sempron

​

Minimum RAM: 2 GB

Small Office/�Home Office

Intel Core i7 or �Intel Core i7 Extreme or AMD Phenom II or �AMD Athlon II

​

Minimum RAM: 4 GB

Mobile

Intel Core i7 Extreme or �Intel Core i7 or�AMD Phenom II or �AMD Turion II

​

Minimum RAM: 2 GB

40 of 42

Putting It All Together

Page 239

Figure 4-38

Discovering Computers 2012: Chapter 4

40

Power

Intel Xeon or�Intel Itanium or�AMD Opteron

Minimum RAM: 8 GB

Enterprise

Intel Core i7 or �Intel Core i7 Extreme or AMD Phenom II or�AMD Athlon II

​

Minimum RAM: 4 GB

41 of 42

Keeping Your Computer �or Mobile Device Clean

Page 240

Discovering Computers 2012: Chapter 4

41

Clean your computer or mobile device once or twice a year

Turn off and unplug your computer or mobile device before cleaning it

Use compressed air to blow away dust

Use an antistatic wipe to clean the exterior of the case and a cleaning solution and soft cloth to clean the screen

42 of 42

Summary

Page 241

Discovering Computers 2012: Chapter 4

42

Components of the system unit

How memory stores data, instructions, and information

Sequence of operations that occur when a computer executes an instruction

Comparison of various personal computer processors on the market today

How to clean the exterior and interior of a system unit