CHAPTER 6 THE SYSTEM UNIT 2 Competencies Describe

CHAPTER 6 THE SYSTEM UNIT

2 Competencies Describe the function of the system clock, expansion slots, boards, and bus

3 System Clock Important measurement indicating speed Located on a small chip Produces electrical beats Synchronizes operations Expressed in gigahertz Faster clock speed, faster computer What is a gigahertz? © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

4 System Clock Controls speed and synchronizes operations Expressed in megahertz Faster the clock

5 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 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

6 Section D . . Expansion Slots and Cards Expansion slot - long, narrow socket on the motherboard into which you can plug an expansion card Graphics card (for connecting monitor) Modem (for transmitting data over phone or cable lines) Sound card (for connecting speakers) Expansion card - small circuit board that provides computer with ability to control storage, input or output device Most computers have 4 - 8 expansion slots Page 88 -89 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

7 Page 88 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

8 PC Cards Do notebook computers also contain expansion slots? Most notebook computers are equipped with a special type of external slot called a PCMCIA slot (personal computer memory card international association) Typically a notebook only has one slot, but the slot can hold more than one PC card (PCMCIA expansion cards) Page 90 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

9 PC card Page 90 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights

10 Commonly Used Expansion Cards Video cards Modem cards Network interface cards (NIC) TV

11 Installing a New Expansion Card Internal devices Tools required Screwdriver Directions Before installing Unplug the computer Ground yourself Installing Follow the directions Page 92 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

12 . . Installing a New Expansion Card Some devices require software, called a device driver The device driver sets up communication between your computer and the device Normally, disk or CD used only once Today’s PCs include Plug and Play (Pn. P) that automatically takes care of these technical details Page 92 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

13 Installing a New Expansion Card For installing a new device, following setup is needed: Inserting the device card into the matching slot Installing the device driver program for the device Configure the system (tedious step, requires sufficient technical background) “Plug and Play” is a new technology for making the device installation procedure much faster and easier. © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

14 “Plug and Play” Hardware and software standards Makes system expansion easy for the user Automatically installs drivers and system configuration System unit recognizes the new device A plug-n-play card requires the user to: • Switch off the system • Insert the card • Open the system again. • System automatically configure itself for the newly installed device -User is asked for the latest device driver. © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

15 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 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

Chapter 16 Section D Input and Output Devices 2 Expansion slots, cards and ports: How does a computer get data from RAM to a peripheral device? Data Bus carries data from one component to another I/O (computer jargon for input/output) refers to collecting data and transporting results. Expansion bus - the segment of the data bus that transports data between RAM and peripheral devices Page 88 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

17 Types of Expansion Buses Industry Standard Architecture (ISA) Peripheral Component Interconnect (PCI) Advanced Graphic Port (AGP) Universal serial bus (USB) Fire. Wire buses HPSB – high performance serial bus Used with digital camcorders & video editing software © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

18 … Types of Expansion Buses The microcomputer motherboard typically has up to three types of expansion slots: ISA - older technology, modems and slow devices PCI - for graphics, sound, video, modem or network cards AGP - for graphics cards Expansion cards are built for only one type of slot Page 89 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

19 AGP slot ISA slot PCI slot Page 89 © 2005 The Mc. Graw-Hill

20 ISA Bus Developed by IBM for personal computers Slow Originally 8 bit, later expanded to 16 bit Still used by some expansion cards Replaced by PCI bus in the near future © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

21 PCI Bus Originally developed to meet demands of graphical user interfaces High speed 32 bit or 64 bit Widely used to connect CPU, memory, and expansion cards © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

22 AGP Bus Dedicated bus for acceleration of graphics performance Replacing the PCI bus

23 Other Bus Types USB Connects directly to the PCI bus on the motherboard Supports external devices without inserting expansion cards for each device HPSB Fire. Wire Similar to USB but faster © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

24 Expansion Ports To connect a peripheral device to an expansion card, you plug a cable from the device into the expansion port Expansion port - any connector that passes data in and out of a computer or peripheral device Page 90 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

25 Power plug socket Keyboard port Mouse port USB ports DB-9 serial port Parallel port (printer) Speaker and microphone jacks Monitor port Modem port Network port Page 90 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

26 Ports Socket for connecting external devices Four common ports Serial Parallel USB Fire.

27 Serial & Parallel Ports Serial Port Data sent one bit at a time Good long distance transmission of data Parallel Port Data sent 8 bits simultaneously Used for short distances © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

28 USB and HPSB Ports USB Port Replacing serial and parallel ports Faster Each port can support more than one device HPSB Port Fire. Wire ports Faster then USB ports © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

29 What’s the best port to use for connecting peripheral devices? USB port Most popular port Most computers feature at least 2 USB ports USB devices Mouse Scanner Printer Joystick Windows automatically recognizes USB devices Page 91 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

30 Cables Connect Input/Output devices Mouse Keyboard Printer Monitor Newer cables AGP graphics monitor USB joy stick; scanner HPSB video camera © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

31 Major types of expansion cables Page 90 -91 © 2005 The Mc. Graw-Hill

32 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 © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.

33 Look to the Future Wireless Technology and PDAs Personal wearable computer POMA® Wireless pointing device, head mounted display Developed by Xybernaut Corporation Currently being evaluated for use in airport security © 2005 The Mc. Graw-Hill Companies, Inc. All Rights Reserved.