Understanding Memory

1

Understanding Memory

• http://upload.wikimedia.org/wikipedia/commons/thumb/1/16/Eprom.jpg/800px-Eprom.jpg

Discovering Computers 2012: Chapter2- 4

Memory

• Bytes and Addressable memory• Memory Sizes• Types of Memory• RAM• Cache• ROM• Flash Memory• CMOS• Memory Access Time

Discovering Computers 2012: Chapter 2-4 3

Objective Overview

Differentiate among the various types of

memory

See Page 209 for Detailed Objectives

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:

Discovering Computers 2012: Chapter 4 4Page 223

The operating system and other system software

Application programs

Data being processed and the

resulting information

Discovering Computers 2012: Chapter 4 5

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 6

Memory

• The system unit contains two types of memory:

Pages 223 - 224

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

Discovering Computers 2012: Chapter 4 7

Memory

Page 224 Figure 4-18

Discovering Computers 2012: Chapter 4 8

Memory

• Three basic types of RAM chips exist:

Page 225 Figure 4-19

Dynamic RAM (DRAM) Static RAM (SRAM) Magnetoresistive

RAM (MRAM)

Discovering Computers 2012: Chapter 4 9

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 10

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 11

Memory

• Memory cache speeds the processes of the computer because it stores frequently used instructions and data

Page 227 Figure 4-22

Discovering Computers 2012: Chapter 4 12

Memory

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

Page 228

Discovering Computers 2012: Chapter 4 13

Memory

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

little power

Pages 228 – 229Figure 4-23

Discovering Computers 2012: Chapter 4 14

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 15

Putting It All Together

HomeIntel Core i5 or

Intel Core 2 i3 or AMD Athlon II orAMD 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

MobileIntel Core i7 Extreme

or Intel Core i7 or

AMD Phenom II or AMD Turion II

Minimum RAM: 2 GB

Page 239 Figure 4-38

Discovering Computers 2012: Chapter 4 16

Putting It All Together

PowerIntel Xeon or

Intel Itanium orAMD Opteron

Minimum RAM: 8 GB

EnterpriseIntel Core i7 or

Intel Core i7 Extreme or AMD Phenom II or

AMD Athlon II

Minimum RAM: 4 GB

Page 239 Figure 4-38

Discovering Computers 2012: Chapter 4 17

Keeping Your Computer or Mobile Device Clean

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

Page 240

Discovering Computers 2012: Chapter 4 18

Video: The Leopard with a Time Machine

CLICK TO START

Discovering Computers 2012: Chapter 4 19

Summary

Differentiate among the various types of

memory

Page 241

Chapter 2

Chapter 2Complete