1. Unit 1 Computer Motherboard

2. Computer systems, such as desktop computers, laptop computers, work stations, and servers, are information handling systems that are utilized by many individuals and businesses today.

3. These computer systems typically include a system board, or motherboard, secured within a chassis [' ʃ æsi] ( 底架 ), and a multitude of ( 许多 ) different internal components such as memory units, processor units, power systems, a cooling system, and various input/output PCI cards.

4. A computer system may also include one or more built-in pe’ripheral devices, including a keyboard, mouse, video display, and both serial and parallel ports.

5. The main board, which is a printed circuit board ( 印刷电路板 ) known as ( 被称为 ) a motherboard, is used to electrically connect these components together.

6. Computers typically contain a plurality [pl ʊ 'ræləti] （多数） of integrated circuit packages that are mounted to a printed circuit board commonly referred to as motherboard.

7. The integrated circuit packages and printed circuit board are typically located within a protective chassis.

8. The motherboard is the base of the computer system. The motherboard is the physical arrangement that contains the system's basic circuitry (['sə:kitri] 电路 ) and components.

9. Motherboards commonly include the basic functional units of a computer such as microprocessor, memory, basic input/output system (BIOS), expansion slots, and interconnecting( 互连 ) circuitry.

10. Additional components can be coupled (['k ʌ pl] 连接 ) to a motherboard through its expansion slots. Electronic system motherboards are becoming increasing integrated to support a growing number of features.

11. While a central processing unit (CPU) performs most computer jobs, it is really a motherboard that brings it all together to turn a CPU into a modern personal computer.

12. A typical motherboard comprises ([kəm'praiz] 包含 ) a large printed circuit board having a number of components mounted (['mauntid] 安装好 的 ) thereon, including a processor coupled to a host or local bus, a chipset, system memory coupled to a memory bus, and a peripheral ([pə'rifərəl] 外设 ) component interconnect (PCI) bus.

13. A chipset mounted to the motherboard by the manufacturer provides core logic that operatively ([' ɔ pərətiv] 有效的 ) links the CPU, the memory modules, and other components of the system.

14. A read only memory (ROM) chip ( 芯片 ) containing the system‘s startup program (firmware ) ([’fə:mw ɛ ə] 固件 ) is also mounted to the motherboard.

15. The chipset bridges the PCI bus with the local bus and bridges the PCI bus to each of an Industry Standard Architecture (ISA) bus and a Small Computer System Interface (SCSI) ( 小型计算机系统接口 ) bus, if present ( 如果存在 ).

16. In addition, a motherboard typically includes input/output (I/O) connectors, floppy disk and hard disk drive connections, as well as circuitry (['sə:kitri] 电路 ) for controlling any built- in peripheral devices e.g., hard disk drives, floppy disk drives.

17. A typical motherboard housed within a personal computer comprises one or more layers of printed conductors( 导线 ) extending at least partially ( 部分的 ) across the motherboard. The printed conductors surface( 浮出 ) at localized regions of the motherboard.

18. Those regions allow connection of integrated or discrete ([di’skri:t] 离散的 ) devices using various connection techniques, such as plug—and— socket( 接插件 ), wire wrap( 绕线连接 ), or solder( 焊接部件 ). Modern motherboard systems further comprise a power saving mode ( 省电 模式 ).

19. Typically, a computer motherboard includes many input/output ports for connecting to various peripherals, and these I/O ports are arranged on the personal computer.

20. Most personal computers also include a dedicated ( 专用的 ) serial port, a dedicated keyboard port, and one or more expansion slots configured ( 配置的 ) to receive expansion cards for augmenting ([ ɔ :g‘mentiŋ] 扩充 ) the PC’s functionality.

21. For example, a network expansion card can be inserted into an expansion slot of a general—purpose PC to provide a port for connecting that PC to a local area network (LAN).

22. Most personal computers are constructed with a single motherboard that provides connection for CPU and other components in the computer. Generally speaking, a motherboard is manufactured （定制的） so that it can accommodate ( 适应 ) dissimilar microprocessors, or microprocessors which respond to differing system bus frequencies or power supply voltages ['vəultid ʒ ].

23. In a typical computer system, a motherboard is integrated with PCI slots to enable customers to plug different PCI cards into the computer for processing output signals. For this reason, the computer chassis typically includes multiple slot openings covered with clamps ( 夹钳 ), which hold the card in place and can be removed before and restored after plugging PCI cards onto the slots.

24. This has been the prevailing ( [pri‘veiliŋ] 流行 的 ), configuration of computer chassis. The motherboard is typically ‘permanently attached to the chassis and is also connected to other internal components via cables or internal connectors.

25. In many systems, the motherboard generally extends in a plane( 在一个平 面上 ) between the chassis and the remaining ( 剩下的 ) internal components of the system. Most motherboards are secured to the chassis by screws.

26. The motherboard is mounted to the chassis of the electronic device via a plurality of screws extending through holes in the board into the chassis. Screws are inserted through the openings in the chassis and into the openings that are provided in the motherboard for this purpose.

27. The mounting holes on the motherboard are often surrounded by a grounding pad ( 接地垫 ). The grounding pad is a conductive （导电的） surface that is used as an electrical ground （电接地） for the motherboard.

28. To enhance the structural integrity （结构完整性） of the computer assembly （装配）, the integrated circuit packages are typically soldered to the printed circuit board.

29. Motherboards and their host computer systems are typically required to meet specified standards for mechanical configuration such that ( 如此 … 以 致 )system failures are reduced and component Interchangeability (['intə,t ʃ eind ʒ ə'biliti] ) is maintained.

30. PC/XT is the original open motherboard standard created by IBM for the first home computer, the IBM-PC. The Baby AT(BAT) was also established by IBM at the inception of ( 在 … 初期 ) the IBM personal computer AT (Advanced Technology).

31. The BAT motherboard has the advantage that it is very common, it is easy to insert add-in cards and the design places the central processing unit (CUP) module near the front of the chassis where it is cooled by incoming air.

32. The BAT motherboard has the disadvantage that there is no expansion room for additional I/O connectors out the back of the motherboard.

33. The LPX standard is based on a design by Western Digital, it allows for smaller cases based on the ATX motherboard by arranging the expansion cards in a riser. LPX 标准是基于 Western Digital 的一个 设计，它基于 ATX 主板适用于更小的 机箱通过将扩展卡插在竖板里。

34. The LPX motherboard has the advantage that it is common. I/O is integrated on the motherboard and easily goes out the back of the chassis and the CPU usually placed near the front of chassis where it is cooled by incoming air.

35. ATX is the evolution of the Baby AT form factor ( 形状系数 ), it is now the most ’popular form factor available today. A full size ATX board is 12 (inches, 英寸 ) wide by 9.6 (inches) deep (305mm*244mm).This allows many ATX form factor chassis to accept microATX boards as well.

36. A motherboard and one or more daughter boards (also referred to as a peripheral card, expansion board, or daughterboard) are used to transfer digital signals between respective assemblies used in a computer or other electronic equipment.

37. The mother and daughter boards may be arranged perpendicular [,pə:pən‘dikjulə] 垂直 to each other ， as in an edge card ( 边缘穿孔卡 ) configuration, depending upon the design of overall ( 总体的 ) product.

38. Daughter boards are coupled to a motherboard via sockets, to expand the functionality of the motherboard. The daughter boards may contain memory modules, or other expansion units to the motherboard.

39. Generally, one or more card connectors are located on a motherboard, each card connector （卡 连接器） for receiving a peripheral card. The daughter boards are added to a computer system to enhance that system's capabilities [,keipə'biləti].

40. A peripheral card may provide a network interface, enhanced audio capability, or enhanced graphics. A peripheral card is typically PCI compatible or ISA compatible, such that the peripheral card (and connector) can be coupled to the PCI bus or ISA bus, respectively.

41. The connection between the daughter boards and the motherboards is generally intended to provide for the transmission of power, ground and electrical signals （电气信号） between the daughterboard and the motherboard.