1. Professor Michael J. Losacco CIS 1110 – Using Computers System Unit Chapter 4

2. Chapter4 2/28 Overview Describe System Unit Components Identify Motherboard Components Describe Processor Functions Explain Computer Data Representation Differentiate Memory Types Differentiate Ports & Connectors

3. Chapter4 3/28 System Unit Case Containing Electronic Components

4. Chapter4 4/28 Common Components Processor Memory Adapter Cards Video Sound Modem Network Ports Drive Bays Power Supply

5. Chapter4 5/28 Motherboard Main Circuit Board in System Unit Contains Processor Memory Adapter Cards Chips Integrated Circuits

6. Chapter4 6/28 Processor Central Processing Unit (CPU) Interprets & Executes Basic Instructions Components Control Unit Directs & Coordinates Operations Arithmetic Logic Unit (ALU) Arithmetic (+-*/) Comparison (=<>) Logical (and or not)

7. Chapter4 7/28 Processor System Clock Controls Timing of All Operations Generates Ticks Regular Electronic Pulses Smallest Unit of Time Recognized by a Device

8. Chapter4 8/28 Processor System Clock Processor Speed Measured by Ticks/Second MHz – One Million Ticks/Second Type 100 Words/Minute = 8 Characters/Second 8088 Processor @ 4.77 MHz Character ► 50,000 Other Tasks ► Character GHz – One Billion Ticks per Second

9. Chapter4 9/28 Processor Machine Cycle Fetch Obtain Instruction From Memory Decode Translate Instruction to Commands Execute Carry Out Command Store Write Result to Memory CPU Executes 1-3+ Cycles per Tick

10. Chapter4 10/28 Processor Machine Cycle Example 1) Fetch instruction: “Get number at address 123456” 2) Decode instruction 3) Execute: ALU finds the number (which is 5) 4) Store: The number ‘5’ is stored in a register 5 – 8) Repeat steps for another number (which is 6) 9) Fetch instruction: “Add number in Reg1 to Reg2” 10) Decode instruction 11) Execute: ALU adds the numbers 12) Store: The answer is stored in a register 13) Fetch instruction: “Display answer on screen” 14) Decode instruction 15) Execute: Display answer on screen

11. Chapter4 11/28 Processor Cooling Systems Heat Sink Component that Cools Processor Heat Pipe Used in Notebooks Liquid Cooling Continuous Fluid Flow Transfers Heat Away

12. Chapter4 12/28 Data Representation Binary Most Computers are Digital Recognize Two Discrete States On / Off Equivalent Numbering System Bits (Binary Digit) Two Unique Digits 0 / 1

13. Chapter4 13/28 Data Representation Byte Eight Bits Grouped Together Represent Numbers Uppercase & Lowercase Letters Punctuation Special Characters 35D35D

14. Chapter4 14/28 Data Representation Coding Systems ASCII PC EBCDIC Mainframe Unicode Other Languages

15. Chapter4 15/28 Memory One or More Chips on Motherboard Each Byte Stored in Unique Location Address Stores Three Basic Categories of Items OS & Other System Software Application Program Instructions Data Being Processed & Resulting Info

16. Chapter4 16/28 Memory Sizes

17. Chapter4 17/28 Memory RAM (Random Access Memory) Read From / Written To by Processor Volatile Content Lost When Power is Absent More = Faster Operation DRAM (Dynamic) Standard SRAM (Static) MRAM (Magnetoresistive)

18. Chapter4 18/28 Memory Location Memory Resides on Small Circuit Board Memory Module Memory Slots Hold Memory Modules On Motherboard

19. Chapter4 19/28 Memory System Requirements Based on Types of Applications Used Cache Speeds Computer Processes Stores Frequently Used Instructions & Data

20. Chapter4 20/28 Memory ROM (Read Only Memory) Stores Permanent Data & Instructions Non-volatile Types Firmware – Permanently Written Data BIOS (Basic Input / Output System) Sequence of Instructions to Start Computer PROM – Blank EEPROM – Electrically Erasable PROM

21. Chapter4 21/28 Memory Flash Non-volatile Can be Erased & Reprogrammed Used in Cell Phone Digital Camera MP3 Player USB Storage

22. Chapter4 22/28 Additional Functionality Expansion Slots & Adapter Cards Expansion Slot Socket on Motherboard Holds Adapter Card Adapter Card Enhances System Unit Provides Connections to Peripherals Plug n’ Play Automatically Configured When Installed

23. Chapter4 23/28 Additional Functionality Port Connects Peripheral to System Unit Connector Joins Cable to Peripheral Male or Female

24. Chapter4 24/28 Additional Functionality Ports & Connectors

25. Chapter4 25/28 Additional Functionality USB (Universal Serial Bus) Printer, Digital Camera, Phone, Flash, etc. Bluetooth Wireless Firewire Data Transfer IrDA Wireless Data Transfer

26. Chapter4 26/28 Bus Pathway Used to Communicate On Motherboard Allows Devices to Communicate with Each Other Data Bus Address Bus Bus Width Word Number of Bits Processor can Use at Once

27. Chapter4 27/28 Other Components Bay Opening Inside System Unit Used to Install Additional Equipment Typically Holds Disk Drives Power Supply Converts AC Power into DC Power Fan Keeps System Unit Components Cool

28. Chapter4 28/28 Maintenance Clean Device Once or Twice a Year Turn Off & Unplug Device Compressed Air to Blow Out Dust Clean Case Exterior Antistatic Wipe Clean Monitor Cleaning Solution & Soft Cloth