CHAPTER 6 THE SYSTEM UNIT Mc GrawHill Technology

CHAPTER 6 THE SYSTEM UNIT Mc. Graw-Hill Technology Education © 2006 by the Mc. Graw-Hill Companies, Inc. All rights reserved.

Competencies Describe the four basic types of system units Discuss how a computer uses binary codes Describe the major system unit components Describe system boards, microprocessors, and memory Describe the function of the system clock, expansion slots, boards, and bus lines Discuss ports, cables, and power supply Page 148 2

System Units Microcomputers Desktop Notebook Tablet PC Handheld Page 150 3

Electronic Data and Instructions Data and instructions are represented electronically Computers recognize digital signals Binary system Bit Byte Page 152 4

Binary Coding Scheme Two state system Off/on electrical states Characters represented by 0 s and 1 s Three types of coding schemes ASCII - American Standard Code for Information Exchange EBCDIC - Extended Binary Coded Decimal Interchange Code Unicode – handles languages with large numbers of characters Page 152 5

Binary Code Uses ASCII Microcomputers EBCDIC Large Computers Unicode International Languages Page 152 6

System Board Connects all components Allows communication between devices Main board or motherboard Circuit board electronic components Sockets Slots Bus lines Page 154 7

Microprocessor Central Processing Unit (CPU ) Two basic components Control unit Arithmetic-logic unit Page 156 8

Microprocessor Chips Chip capacities are expressed in word sizes Types of microprocessor chips CISC chips: Complex instruction set computer chips Most widely used design Used by Intel RISC chips: Reduced instruction set computer chips Uses fewer instructions Design is simpler and less costly Used by the Power. PC Page 157 9

Specialty Processors Graphics coprocessors Parallel processors Smart cards Page 157 10

Memory Holding area for data, instructions, and information Types of memory chips RAM – holds programs and data ROM – fixed start-up instructions CMOS – flexible start-up instructions Page 158 11

Memory Capacity Unit Capacity Megabyte (MB) 1 billion bytes Gigabyte (GB) 1 million bytes Terabyte (TB) 1 trillion bytes Page 159 12

System Clock Important measurement indicating speed Located on a small chip Produces electrical beats Synchronizes operations Expressed in gigahertz (GHz) (billions of beats per second) Faster clock speed, faster computer Page 160 13

Expansion Slots and Cards Allow for new devices to be added Open architecture Slots provide for expansion Expansion cards are also called … Plug-in boards Controller cards Adapter cards Interface cards Page 161 14

Commonly Used Expansion Cards Video cards (graphics cards) Sound cards Modem cards (internal modems) Network interface cards (NIC) TV tuner cards PC cards (PCMCIA cards) Modem Card Inserting a PC card into a notebook Page 161 15

Plug and Play Set of hardware and software standards developed by Intel, Microsoft, and others Creating devices that are able to configure themselves when installed Page 161 16

Bus Lines Connect parts of the CPU to each other Data roadway for traveling bits Measured as bus width More lanes, faster traffic Two basic categories System buses Expansion buses Page 164 17

Types of Expansion Buses Industry Standard Architecture (ISA) Peripheral Component Interconnect (PCI) Accelerated Graphics Port (AGP) Universal serial bus (USB) Fire. Wire buses Bus Pathway Page 164 18

Ports Socket for connecting external devices Four common ports Serial Parallel USB Fire. Wire Cables are used to connect exterior devices to the system via the ports Page 165 Ports 20

Power Supply Computers require direct current (DC) DC power provided by converting alternating current (AC) from wall outlets or batteries Desktop computers use power supply units Notebooks and handhelds use AC adapters Power Supply Unit AC adapter Page 166 21

A Look to the Future Xybernaut Corporation Wearable computers Called POMA Includes… Windows CE Wireless pointing device Head-mounted display MP 3 player Abridged Windows Office programs Page 167 22

Discussion Questions Describe the four basic types of system units. Describe the two basic components of the CPU. What are the differences and similarities between the three types of memory? Identify five expansion cards and describe the function of each. Identify and describe four standard ports. Page 174 23