Enhanced A+ Guide to Managing and Maintaining Your PC Third Edition

Chapter 1

How Computers Work

You Will Learn… 1

 About the functions performed by different hardware components of a microcomputer  About the three kinds of software and how they relate to one another and to hardware  How the CPU uses primary and secondary storage to manage software

Hardware and Software 1

 Hardware • Physical components of the computer  Monitor  Keyboard  Memory chips  Hard drive  Software • Set of instructions that directs the hardware to accomplish a task

1 Chauffer Analogy

1 Functions of Hardware

1 Binary Number System

Hardware 1

 Central processing unit • • • Most important hardware device Receives input and sends output Stores data and instructions; performs calculations  Requirements of hardware devices • • • Method for CPU to communicate with the device Software to instruct and control the device Electricity to power the device

1 Hardware Used for Input and Output

 Ports • Physical connectors that allow a cable from a peripheral device to be attached  Input devices • • Keyboard Mouse  Output devices • • Monitor Printer

1 Ports

1 Input Devices

1 Output Devices

1 Hardware Inside the Computer Case

 System board  Permanent storage • Floppy drive • • Hard drive CD-ROM drive   Power supply Circuit boards • • CMOS (most CPUs) TTL  Cables

1 Hardware Inside the Computer Case

CMOS Chips 1

 Require less electricity  Hold data longer after electricity is turned off  Are slower  Produce less heat

The System Board 1

 Largest and most important circuit board  Contains the CPU

1 The System Board

1 Major Components of System Boards

 For processing • • CPU Chip set that supports CPU by controlling many system board activities  For temporary storage • • RAM Cache memory continued

1 Major Components of System Boards

  Allow CPU to communicate with other devices • BUS • Expansion slots Firmware and setup information • • Flash BIOS memory chip CMOS configuration chip  Electrical system • Power supply connections

1 Components Used Primarily for Processing

 CPU or microprocessor • Executes most computer processes  Chip set • Relieves CPU of some processing • Provides careful timing of activities to increase overall speed  Coprocessor • Supports and enhances function of some older CPUs (pre-1995)

1 The CPU

1 Temporary (Primary) Storage Devices

 Used by the CPU to process data and instructions  Provided by RAM (random access memory devices) • • SIMMS (single inline memory modules) DIMMS (dual inline memory modules)  Cache memory

1 SIMMS and DIMMS

Cache Memory 1

 For new CPUs • Stored inside CPU housing on a memory chip that sits close to the CPU microchip  For older CPUs • Stored on the system board either in individual chips or on memory modules called COAST (cache on a stick)

1 Cache Memory

1 Permanent (Secondary) Storage Devices

 Remote to the CPU  Permanently hold data, even when PC is turned off  Most popular devices: • • • • Hard disks Floppy disks Zip drives CD-ROMs

1 Hard Drives