The System Board

1. Chapter 3 The System Board

2. You Will Learn� What physical components are on the system board How the system board Transports data Follows programming logic Coordinates timing and execution of each processing task About the recent evolution of several system-board components How to set the CPU and system bus frequency for the system board

3. Types of System Boards Primary purpose of system board To house the CPU and allow all devices to communicate with it Two popular types AT (older) ATX (newer) AT and ATX differ not in overall performance, but in size, convenience features, type of case into which they fit, and type of power connection they have

5. Summary of AT and ATX Boards

6. System Board Components CPU and its chip set System clock ROM BIOS CMOS configuration chip and its battery RAM RAM cache System bus with expansion slots Jumpers Ports that come directly off the board Power supply connections

7. System Board

8. System Board

9. Selection of a System Board Determines� CPU types and speeds Chip set on the board Memory cache type and size Types and number of expansion slots: EISA, PCI, and AGP Type of memory: ECC, EDO, SDRAM, SIMMs, or DIMMs Maximum amount of memory you can install on the board; incremental amounts by which you can upgrade memory

10. Selection of a System Board Determines� Type of case ROM BIOS Type of keyboard connector Presence/absence of proprietary video &/or proprietary local bus slots Presence/absence of IDE adapters and SCSI controller Presence/absence of COM ports, LPT ports, and mouse port

11. Considerations when Selecting a System Board Designed so that long expansion cards don�t get in the way of the CPU or other devices? How many different CPUs can it support? What bus speeds, type of memory, and system BIOS does it support? Does it use many embedded devices?

12. Considerations when Selecting a System Board Does it fit the case? Does it support the legacy cards? How long is the warranty? How extensive and user-friendly is the documentation? How much support does the manufacturer supply?

13. Major Manufacturers of System Boards

14. The System Clock Keeps the beat for system-board activities Clock frequency Measured in megahertz (MHz) Clock speed Determined by a crystal or oscillator located on the system board Wait state A clock tick in which nothing happens Used to slow down the CPU so the rest of system-board activity can keep up

15. The CPU and the Chip Set Microprocessor chips are made by Intel or one of its competitors Common model numbers 8088, 8086, 80286, 386, and 486 (historical interest) Pentium (Intel) or X86 (AMD and Cyrix)

16. Attributes for Rating CPUs CPU speed (average speed for new CPU is about 550 MHz) Efficiency of programming code Word size (internal data path size) Data path Maximum number of memory addresses (4096 megabytes or 4 gigabytes)

17. Attributes for Rating CPUs Amount of memory included with the CPU (called internal cache, primary cache, level 1, or L1 cache) Multiprocessing ability Special functionality

18. Relating CPU Attributes to Bus Architecture Number of memory addresses Determined by the number of traces, or wires, on the bus that are used for memory addresses Data path size Determined by the width of the bus data path, or the number of parallel wires in the bus data path

19. The Earlier Intel CPUs

20. Comparing Chips Bus speed Speed or frequency at which data moves on a bus Common speeds: 66 MHz, 75 MHz, 100 MHz, 1433 MHz, and 200 MHz Memory bus (also called system bus or host bus) Bus between CPU and memory on the system board Processor speed Speed or frequency at which the CPU operates Usually expressed in MHz

21. Comparing Chips Multiplier Factor by which the bus speed or frequency is multiplied to get the CPU clock speed Memory cache A small amount of faster RAM that stores recently retrieved data, in anticipation of what the CPU will request next, thus speeding up access

22. Memory Cache Terms Internal cache Memory cache that is faster than external cache and is contained inside 80486 and Pentium chips Also referred to as primary, Level 1, or L1 cache External cache Static cache memory, stored on the system board or inside CPU housing, that is not part of the CPU Also called level 2 or L2 cache

23. Memory Cache Terms Frontside bus The bus between the CPU and the memory outside the CPU housing Backside bus The bus between the CPU and the L2 cache inside the CPU housing

24. Location of L1 and L2 Caches

25. Types of Pentium CPUs

26. Types of Pentium CPUs

27. Classic Pentium The first Pentium (introduced in 1993) No longer manufactured

28. Pentium MMX (Multimedia Extension) Targets the home market Speeds up graphical applications Performs well with games and multimedia software

29. Pentium Pro Recommended for 32-bit applications that rely heavily on fast access to large amounts of cache memory First Pentium to offer Level 2 cache inside CPU housing Popular for computing-intensive workstations and servers Does not perform well with older 16-bit applications software written for DOS or Windows 3.x

30. Pentium II Designed for graphics-intensive workstations and servers Works well with 3-D graphic manipulation, CAD, and multimedia presentations First Pentium to use a slot instead of a socket to connect to the system board Intel chose to patent Slot 1, forcing competitors to stay with slower socket technology Can use the 100-MHz memory bus with processor speeds up to 450 MHz

31. Pentium II Celeron processor Low-end Pentium II processor that targets the low-end multimedia PC market segment Uses Level 2 cache within processor housing Works well with Windows 9x Xeon processor Fast, high-end Pentium II processor designed exclusively for powerful servers and workstations Supports up to eight processors in one computer Recommended for use with Windows NT and UNIX operating systems

32. Pentium III Uses either a slot or a socket Runs with the 100-MHz or 133-MHz memory bus with a processor speed up to 1 GHz Introduced Intel�s new performance enhancement called SSE, a new instruction set designed to improve multimedia processing even further

33. Pentium III

34. Pentium III Xeon High-end Pentium III processor Runs on the 133-MHz system bus Designed for mid-range servers and high-end workstations Uses a 330-pin slot called the SC330 (slot connector 330), sometimes called Slot 2 Is contained within a cartridge called a Single Edge Contact Cartridge (SECC)

35. Primary Pentium Competitors AMD Cyrix For the latest information www.adm.com www.cyrix.com www.intel.com

36. The Pentium Competitors  Neither manufactured today; many still in use AMD K5 offers unusual assortment of clock speeds and bus speeds Cyrix 6x86 uses external bus speed of 75 MHz, not supported by Intel for its chip set (disadvantage)

37. Competitors of the Advanced Pentiums

38. Competitors of the Advanced Pentiums Cyrix processors use sockets that can also be used by Intel Pentium processors AMD processors that can run on a 100-MHz system bus use Super Socket 7 that supports an AGP (accelerated graphics port) video slot and 100 MHz system bus

39. Cyrix III Recently acquire by VIA

40. AMD Athlon

41. CPUs That Use RISC Technology CPU is limited to a very few instructions that can execute in a single clock cycle Can process much faster when few complex calculations are required Ideal for video or telecommunications applications Easier and cheaper to manufacture

42. CPU Cooling Fans Maintain temperature at 90 to 110 degrees F Used to prevent system errors and to prolong the life of the CPU

43. CPU Cooling Fans

44. PPGA Form Factor

45. CPU Slots and Sockets The physical connection used to connect the CPU to the system board Slots 1 and 2 are proprietary Intel slots Slot A is a proprietary AMD slot Current CPU sockets are called zero insertion force (ZIF) sockets and have a small lever on the side of the socket that lifts the CPU up and out of the socket

47. CPU Slots and Sockets

48. CPU Slots and Sockets

49. The Chip Set Set of chips on the system board that collectively controls the memory cache, external buses, and some peripherals

51. Accelerated Hub Architecture of the Intel i800 Series

52. Chip Set Manufacturers Intel Corporation Cyrix Corporation Silicon Integrated Systems Corp. (SiS) Ali, Inc. Standard Microsystems Corp. United Microelectronics Corp. VIA Technology, Inc. combined with AMD, Inc. VLSI Technology

53. Advantages of Intel Chip Sets More compatible with Pentium family of CPUs Huge investment in research and development has led to invention of: PCI bus Universal serial bus Advanced graphics port (AGP) Accelerated Hub Architecture

54. ROM BIOS There is one ROM chip on the system board that contains BIOS, which manages the startup process (startup BIOS) and many basic functions of the system (system BIOS) Identifying name of BIOS manufacturer Appears at beginning of boot process On top of the chip (larger than most chips)

55. ROM BIOS Does the BIOS support Plug and Play? Does the BIOS support large hard drives? Is the BIOS chip a Flash ROM chip?

56. Plug and Play BIOS Plug and Play A technology in which the operating system and BIOS are designed to automatically configure new hardware devices to eliminate system resource conflicts (such as IRQ and port conflicts) Common in ROM BIOS made after 1994 ESCD (extended system configuration data)

57. BIOS Communicating Well with Hardware and Software

58. When BIOS Is Incompatible with Hardware or Software In the past, most users upgraded BIOS because new hardware was incompatible with it Sometimes need to upgrade BIOS to accommodate new software (such as Plug and Play)

59. Flash ROM EEPROM (electronically erasable programmable read-only memory) Allows you to upgrade system BIOS without having to replace the ROM chip

60. General Method for Upgrading Flash ROM Set a jumper on the system board telling the BIOS to expect an upgrade Copy upgrade BIOS software to a bootable disk Boot from the disk and follow menu options to upgrade the BIOS Set the jumper back to its original setting, reboot the system, and verify that all is working

61. Sample Web Site for Flash ROM BIOS Upgrades

62. RAM (Random Access Memory)

63. Types of RAM Dynamic RAM (DRAM) Most commonly used type of system memory Requires refreshing every few milliseconds Holds data for a very short time Less expensive than static RAM Static RAM (SRAM) Holds data until power is turned off without need for refreshing More expensive than traditional DRAM

64. Most Popular Types of RAM Modules

65. Prevalent Memory Technologies

66. Kinds of Static Cache Memory L1 Contained on the CPU microchip L2 External to the chip Housed either on the system board or inside the CPU case

67. Buses and Expansion Slots Earliest PC Had only a single and simple bus (8-bit ISA bus) Today�s PCs Have four or five buses, each with different speeds, access methods, and protocols

68. Bus Evolution Data path and speed Local buses (system buses) Work in sync with the CPU and the system clock Example: memory bus Expansion buses Work asynchronously with the CPU at a much slower rate Example: ISA bus

69. System-board Buses in Common Use

70. System-board Buses in Common Use

71. Why So Many Buses? Speeds of different hardware components evolve at different rates Single speed for all components is no longer practical

72. What a Bus Does Draws electrical power Carries control signals that coordinate all activity Passes memory addresses from one component to another Passes data

73. Buses ISA bus 8-bit industry standard architecture bus used on the original 8088 PC Later revised to have a 16-bit path Micro channel architecture (MCA) bus A proprietary IBM PS/2 bus, seldom seen today, with a width of 13 or 32 bits and multiple master control, which allowed for multitaskiing EISA (extended ISA) bus 32-bit bus that can transfer 4 bytes at a time at a speed of about 20 MHz

74. Buses Universal serial bus (USB) Designed to make installation and configuration of I/O devices easy, providing room for as many as 127 devices daisy-chained together Uses only a single set of resources for all devices on the bus Expected to eventually replace serial and parallel ports Windows NT does not support it, but Windows 95 with the USB update, Windows 98, and Windows 2000 do

75. USB Ports

76. FireWire or i.Link or 1394 An expansion bus that can also be configured to work as a local bus Similar in design to USB, using serial transmission of data, but faster Supports data speeds as high as 1.2 Gbps Viable option for connecting network cards, camcorders, DVD, and other high-speed, high-volume devices

77. FireWire or i.Link or 1394 Likely to replace SCSI, providing an easy method to install and configure fast I/O devices Must be supported by the operating system IEEE 1394.3 New standard developed by the 1394 Trade Association Designed for peer-to-peer data transmission

78. Local I/O Buses A local bus that provides I/O devices with fast access to the CPU Must connect to the CPU by way of the memory bus

79. VESA Local Bus Expansion Slot

80. PCI Bus Now the standard local I/O bus not only with Pentium CPUs but also with RISC CPUs Has a 32-bit data path and runs at 33 MHz when the system board runs at 66 MHz Advantage Devices connected to it can run at one speed while the CPU runs at a different speed Interfaces with the expansion bus and the memory bus, serving as the go-between for the two, controlling the input and output to the expansion bus

81. PCI Bus Expansion Slots

82. Accelerated Graphics Port A slot on a system board for a video card that provides transfer of video data from the CPU that is synchronized with the memory bus Does not allow for expandability; can only support a single card Runs at same speed as the memory bus, connects directly to it, and has a 32-bit-wide data path

83. Accelerated Graphics Port Most powerful feature: DIME (direct memory execute) To work at full potential, system board must run at minimum of 100 MHz

84. Accelerated Graphics Port

86. Audio Modem Riser (AMR) A slot on some newer system boards that can accommodate a small modem card or sound card Makes it possible to add the card at a low cost without using up a PCI or ISA slot

87. System Board Speeds

88. On-Board Ports Ports that are directly on the system board, such as a built-in keyboard port or on-board serial port When buying a new computer or system board, look for the ability to disable ports, floppy drive connectors, or hard drive connectors coming directly from the system board by changing the hardware configuration

89. On-Board Ports

90. Hardware Configuration Communicates to the CPU what hardware components are present in the system and how they are set up to interface with the CPU Provided on system board in four ways: DIP switches Jumpers CMOS Software

91. Setup Stored on a CMOS Chip Retains data even when computer is turned off

92. Setup Stored on a CMOS Chip

94. Chapter Summary System board Central site of computer logic circuitry Location of the most important microchip in the computer, the CPU