1. Copyright 2003 The McGraw-Hill Companies, Inc. 1 44 CHAPTER The System Unit computing ESSENTIALS    

2. Copyright 2003 The McGraw-Hill Companies, Inc. 2 Competencies System unit types Coding Memory and chips Cards and buses Ports and cables computing ESSENTIALS    

3. Copyright 2003 The McGraw-Hill Companies, Inc. 3 System Unit Types System Unit Houses electronic components Basic components System board Microprocessor Memory Types of System Units Desktop Notebook Personal Digital Assistant computing ESSENTIALS    

4. Copyright 2003 The McGraw-Hill Companies, Inc. 4 Desktop Units Non-portable Input/Output devices located outside the system cabinet computing ESSENTIALS    

5. Copyright 2003 The McGraw-Hill Companies, Inc. 5 Notebook Unit Portable Monitor attached by hinges Keyboard and pointing devices integral to the system unit computing ESSENTIALS    

6. Copyright 2003 The McGraw-Hill Companies, Inc. 6 PDA Units Smallest system unit All input/output and secondary storage devices integral to the system unit computing ESSENTIALS    

7. Copyright 2003 The McGraw-Hill Companies, Inc. 7 Electronic Data & Code Binary System 0s and 1s Each 0 or 1 is a bit 8 bits = 1 byte computing ESSENTIALS    

8. Copyright 2003 The McGraw-Hill Companies, Inc. 8 Binary Coding Scheme American Standard Code for Information Interchange (ASCII) Extended Binary Coded Decimal Interchange Code (EBCDIC) Unicode computing ESSENTIALS    

9. Copyright 2003 The McGraw-Hill Companies, Inc. 9 ASCII Widely used in microcomputers 1 byte = 1 character Examples Letter R is represented by 0101 0010 Number 3 is represented by 0011 0011 Character % is represented by 0010 0101 computing ESSENTIALS    

10. Copyright 2003 The McGraw-Hill Companies, Inc. 10 EBCDIC Developed by IBM Used in mainframe computers 1 byte = 1 character Examples Letter R is represented by 1101 1001 Number 3 is represented by 1111 0011 Character % is represented by 0110 1100 computing ESSENTIALS    

11. Copyright 2003 The McGraw-Hill Companies, Inc. 11 Unicode Developed by Unicode, Inc. with support from Apple, IBM, and Microsoft Used to support international languages such as Japanese and Chinese 2 bytes = 1 character computing ESSENTIALS    

12. Copyright 2003 The McGraw-Hill Companies, Inc. 12 System Board Connects all components Data path between devices Also called the main board or motherboard computing ESSENTIALS    

13. Copyright 2003 The McGraw-Hill Companies, Inc. 13 System Board Components Sockets Connection points on the system board Chips Tiny circuit boards etched into silicon wafers Carrier Package Connects mounted chips into sockets computing ESSENTIALS    

14. Copyright 2003 The McGraw-Hill Companies, Inc. 14 Microprocessor The “brains” of the computer system Location of the Central Processing Unit (CPU) Chip capacity expressed in word size 16 bit, 32 bit, 64 bit Larger the word size faster the computer computing ESSENTIALS    

15. Copyright 2003 The McGraw-Hill Companies, Inc. 15 CPU Control unit Directs the movement of electronic signals between memory and the ALU Arithmetic-logic unit (ALU) Arithmetic operations Fundamental math operations Logical operations Compares data computing ESSENTIALS    

16. Copyright 2003 The McGraw-Hill Companies, Inc. 16 Common Microprocessors CISC chip Complex Instruction Set Computer Intel’s Pentium, Itanium chips, AMD Athlon, Hammer chips RISC chip Reduced Instruction Set Computer Simpler, cheaper then RISC chips Motorola PowerPC chip, DEC Alpha chip computing ESSENTIALS    

17. Copyright 2003 The McGraw-Hill Companies, Inc. 17 Other Microprocessors Smart Cards Plastic card that contains a specialized processor chip Stores more than 80 times data of conventional magnetic strip Used in credit cards, identification cards, phone cards computing ESSENTIALS    

18. Copyright 2003 The McGraw-Hill Companies, Inc. 18 Memory Holding area for data and instructions Three types Random-access memory (RAM) Read-only memory (ROM) Complementary metal- oxide semiconductor (CMOS) computing ESSENTIALS    

19. Copyright 2003 The McGraw-Hill Companies, Inc. 19 Random-access Memory Holds currently running programs and data being processed by the CPU Volatile storage Contained data is lost when computer is turned off Virtual memory RAM pages saved to secondary storage until needed by CPU computing ESSENTIALS    

20. Copyright 2003 The McGraw-Hill Companies, Inc. 20 Special RAM Types RAM cache Frequently accessed data Acts as high-speed, temporary holding area between CPU and RAM Faster processing results Flash RAM Data is retained even if power disrupted Commonly used in cell phone, digital cameras computing ESSENTIALS    

21. Copyright 2003 The McGraw-Hill Companies, Inc. 21 Read-Only Memory Programs and data are permanently encoded CPU can only retrieve data Nonvolatile, cannot be changed by the user Used for storing special instructions, such as computer startup computing ESSENTIALS    

22. Copyright 2003 The McGraw-Hill Companies, Inc. 22 Complementary Metal-Oxide Semiconductor Provides the flexibility and expandability for a computer system Saves data even when computer power is shut off Contents can be changed by the user Stores information such as amount of memory, type of keyboard, mouse computing ESSENTIALS    

23. Copyright 2003 The McGraw-Hill Companies, Inc. 23 Memory Measure UnitCapacity Kilobyte (KB)1,000 bytes Megabyte (MB)one million bytes Gigabyte (GB)one billion bytes Terabyte (TB)one trillion bytes computing ESSENTIALS    

24. Copyright 2003 The McGraw-Hill Companies, Inc. 24 System Clock Special chip that produces precise electrical impulses Used to coordinate and synchronize computer operations Expressed in megahertz or gigahertz Faster clock speed, faster computer computing ESSENTIALS    

25. Copyright 2003 The McGraw-Hill Companies, Inc. 25 Expansion Slots Slots provided to add expansion cards to the system unit Used on open architecture system boards computing ESSENTIALS    

26. Copyright 2003 The McGraw-Hill Companies, Inc. 26 Expansion Cards Expansion cards used to connect to devices outside the system unit Controller cards, Adapter cards, Interface cards, plug-in boards Usually have ports to connect the card to a device outside the system unit computing ESSENTIALS    

27. Copyright 2003 The McGraw-Hill Companies, Inc. 27 Types of Expansion Cards Network interface cards (NIC) Modem cards Sound cards Video cards SCSI adapter TV tuner cards PCMCIA cards computing ESSENTIALS    

28. Copyright 2003 The McGraw-Hill Companies, Inc. 28 “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 computing ESSENTIALS    

29. Copyright 2003 The McGraw-Hill Companies, Inc. 29 Bus Lines More lines, the faster data can travel 64 bit data bus is faster than a 32 bit Data pathways that link parts of the CPU together and components to the CPU computing ESSENTIALS    

30. Copyright 2003 The McGraw-Hill Companies, Inc. 30 Principal Bus Architectures Industry Standard Architecture (ISA) Peripheral Component Interconnect (PCI) Advanced Graphic Port (AGP) Universal Serial Bus (USB) High performance Serial Bus (HPSB) computing ESSENTIALS    

31. Copyright 2003 The McGraw-Hill Companies, Inc. 31 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 computing ESSENTIALS    

32. Copyright 2003 The McGraw-Hill Companies, Inc. 32 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 computing ESSENTIALS    

33. Copyright 2003 The McGraw-Hill Companies, Inc. 33 AGP Bus Dedicated bus for acceleration of graphics performance Replacing the PCI bus for transfer of video data computing ESSENTIALS    

34. Copyright 2003 The McGraw-Hill Companies, Inc. 34 Other Bus Types USB Connects directly to the PCI bus on the motherboard Supports external devices without inserting expansion cards for each device HPSB FireWire Similar to USB but faster computing ESSENTIALS    

35. Copyright 2003 The McGraw-Hill Companies, Inc. 35 Ports Four common port types Serial Parallel USB FireWire computing ESSENTIALS     Sockets that connect external devices to the system unit

36. Copyright 2003 The McGraw-Hill Companies, Inc. 36 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 computing ESSENTIALS    

37. Copyright 2003 The McGraw-Hill Companies, Inc. 37 USB and HPSB Ports USB Port Replacing serial and parallel ports Faster Each port can support more than one device HPSB Port FireWire ports Faster then USB ports computing ESSENTIALS    

38. Copyright 2003 The McGraw-Hill Companies, Inc. 38 Cables Connect Input/Output devices Mouse Keyboard Printer Monitor Newer cables AGP graphics monitor USB joy stick; scanner HPSB video camera computing ESSENTIALS    

39. Copyright 2003 The McGraw-Hill Companies, Inc. 39 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 computing ESSENTIALS    