The System Unit

1. Chapter 5 The System Unit

2. Overview • Discuss the Types of System Units • Describe System Boards • Discuss Processors • Discuss Memory • Discuss Expansion Slots and Cards • Bus Lines, Bus Widths, Expansion Buses • Describe Ports • Discuss Power Supplies • Discuss Numbers and Characters

3. System Unit Types • Desktops • Tower Unit • All-in-one • Notebooks • Laptops • Netbooks • Tablets • Handhelds

4. System Board • AKA Motherboard • All Components Connect to It • All External Devices Connect to It • Acts as Data Path and Traffic Monitor • Provides Sockets • Connection Point For Chips

5. System Board Components • Chips • AKA Semiconductor, Integrated Circuit • Tiny Circuit Boards on Silicon Squares • Mounted on Carrier Packages • Slots • Connection Points for Circuit Boards • Provide Expansion Capability • Bus Lines • Communication Pathways for Components

6. Microprocessor • AKA Central Processing Unit or Processor • Brain of the Computer System • Components • Control Unit • Directs Movement of Electronic Signals • Between Memory, ALU, Input and Output Devices • Arithmetic-logic Unit (ALU) • Arithmetic and Logical Operations

7. Microprocessor Chips • Chip Capacities Expressed in Word Size • Word • Number of Bits Processed at a Time • 64-bit Word Standard • Clock Speed • Processing Speed • Times Per Second CPU Processes Data

8. Microprocessor Chips • 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. Microprocessor Chips • Multi-Core Chip • Multiple Separate and Independent CPUs • Parallel Processing • Divide Tasks that can be Distributed Across Each Core • Supported by Windows 8 and Mac OS X • Coprocessors • Used to Improve Specific Operations • e.g., Graphics Processing Unit (GPU)

10. Memory • Holding Area • For Data, Instructions, and Information • RAM (Random-access Memory) • Volatile • Holds Program Instructions and Data • That CPU is Presently Processing

11. Memory • Sizes

12. Memory • Cache Memory • Temporary High-speed Holding Area • Between Memory and CPU • Stores Most Frequently Used Data • ROM (Read-only Memory) • Non-volatile, Cannot be Updated • Flash Memory • Non-volatile, Can be Updated

13. Expansion Slots and Cards • Allow for System Expansion • Graphics Cards • Sound Cards • Network Interface Cards (NIC) • Wireless Network Cards • Plug and Play • ExpressCard

14. Bus Lines • Pathway for Bits • Travel to/from CPU and Components • Bus Width • Number of Bits that Can Travel at Once • Categories • System Bus • Expansion Bus

15. Ports • Sockets for External Devices • Connects to System Board or Cards • Standard Ports • VGA, USB, Firewire, Ethernet • Cables

16. Power Supply • Convert AC to DC • Power System Unit Components • AC Adapters • Notebooks and Handhelds • Can Recharge Batteries

17. Electronic Data and Instructions • Analog Signals • Represent Different Tones, Pitches, Volume • Digital Electronic Signals • Represent Two Discrete States • On / Off • Recognized By Computers • Binary is the Equivalent Numbering System

18. 3 5 D Numeric Representation • Binary System • Bit (Binary Digit) • 2 Possible Digits • On = 1; Positive Charge • Off = 0; No Charge • Byte • Eight Bits Grouped Together • Represent Letters, Numbers, Punctuation • Hexadecimal System • 16 Possible Digits

19. Character Encoding • ASCII • American Standard Code for Information Interchange • Microcomputers • EBCDIC • Extended Binary Coded Decimal Interchange Code • Mainframe • Unicode • Uses 16 bits

20. Careers in IT • Computer Technicians • Repair and Install Components and Systems • Work On PCs, Mainframes, Networks, Printers • Associate Degree or Computer Repair Cert • Annual Salary of $31,000 - $46,000