Being able to recognize a system unit is a good start, but when you are working with the various computer components, you must be able to work beyond the system unit. For example, when you are replacing a part within a system unit, you must be sure that you can work with the system components properly. Therefore, the ability to identify system unit components is an integral part of the background knowledge that every computer technician should have.
The System Board
Deﬁnition: The system board is the personal computer component that acts as the backbone for the entire computer system. Sometimes called the motherboard, it consists of a large, ﬂat circuit board with chips and other electrical components on it. Some components are soldered directly to the board, and some are slots or sockets where other components can be added and removed easily.
Figure: A system board.
System Board Features
Because features that are built into the design of the system board cannot be changed without replacing the whole system board, most system boards include only the standard features that most users want—those that will not change much in the near future. By omitting features that some users do not use, such as SCSI connections, system board manufacturers can keep the cost of their boards low. By allowing users to buy components such as high-end video cards with the speed and features they want, and letting the users attach the cards to the system board, the designers build in ﬂexibility that most users appreciate. Computer makers who sell complete systems ﬁnd it is cheaper to build a system board with components such as the network interface card (NIC), modem, sound card, video card, and all other features built in, rather than add interface cards to a standard system board.
Common System Board I/O Interfaces
Interfaces on the system board allow you to connect many different components. Some common interfaces found on system boards include:
Deﬁnition: The central processing unit (CPU), sometimes called the microprocessor or just the processor, is the real brains of the computer and is where most of the calculations take place. On most personal computers, the CPU is housed in a single microprocessor module that is installed on the system board in a slot or socket.