Learning Exercise

You can experiment with conversions between binary, decimal, and hexadecimal using the Microsoft Calculator accessory.

Using the Windows operating system, click the Start button, select Programs, then select Accessories, and then select Calculator. To perform the functions required in this exercise you must click the calculator's View menu and select Scientific. To use the calculator for data conversion, click its Dec radio button to put the calculator into decimal mode, type a number, and then click the Hex radio button to convert the number to hexadecimal. You can convert from hexadecimal to decimal as well; the A-F keys are enabled whenever you are in hexadecimal mode. What is the hexadecimal representation of the number 255? What is the decimal equivalent of 0x4D2?

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Unit 2. Hardware Systems

This unit covers computer hardware—the components that make up a computer system and how they work together. First, you will learn about how the computer processes information and how memory works. Then you will learn about how data can be moved among components inside and outside the system unit. You will also become familiar with different media for storing data. By the end of this unit, you should have a basic understanding of how a computer works. Understanding this unit will also help you become an informed consumer of computer equipment.

Reading Sequence: 2.1 Processor and Memory 2.2 Peripherals 2.3 Storage Devices 2.4 Putting Together the Hardware Components 2.5 Improving Computer Performance

              

Assessments: Exercise 2

To guide you through the hardware components that will be covered in this unit, the diagram below illustrates a top-level view of the components in a computer system.

Figure 1 Component overview

The microprocessor, also called the processor, is the main component that executes instructions stored in the main memory. The microprocessor is sometimes referred to as the "brain" of the computer system, making decisions and sending commands to the other components to complete a set of instructions. The main memory stores instructions to be executed by the microprocessor. The data stored in main memory is lost when the computer is turned off. In contrast to main memory, storage devices such as CD-ROM drives and floppy disk drives store data permanently even when the computer is turned off.

Peripherals enable data input and output. Examples of peripheral devices include the monitor, the printer, the keyboard, and the mouse. The peripherals also include mechanisms that allow data to be transferred in and out of a computer system.

The chipset acts as the traffic cop controlling the flow of data and coordinating interactions among components in the system. Components pass data through the chipset, and the chipset monitors the data flow and passes data to other components.

We will now visit an example of how these components work together. In this example, the computer system completes a request to open a file and display the opened file on the monitor. The following four steps are taken to complete the task:

1. The microprocessor sends instructions to the storage devices (via the chipset) requesting the specified file to be loaded into main memory.

2. The storage devices send the file through the chipset to main memory.

3. The microprocessor fetches the file contents from main memory.

4. The microprocessor sends the display data to the monitor via the chipset.

Below is a diagram of the data flow between components.

Figure 2 Data flow in a computer system

In each section of this unit, you will learn more about the major components illustrated in the diagram above and gain more in-depth understanding of how these components work together. To help you become familiar with the physical appearance of hardware components, the image below illustrates the major components inside a system unit. The image is followed by brief descriptions of components labeled in the image.

Figure 3 Components inside a computer

A. Motherboard

Provides sockets for microprocessor and memory chips, slots for circuit boards, and the circuitry that enable electrical signals to travel from component to component. Most of the hardware components inside the system unit are attached to the motherboard.

B. Power supply

Provides electrical power to the computer system.

C. Microprocessor

Processes instructions stored in main memory. Sometimes, the microprocessor is found underneath a cooling fan to prevent it from overheating.

D. Expansion slot

Serves as a socket on the motherboard into which an expansion card maybe inserted.

E. Expansion card

Enables a computer to control peripheral devices such as the monitor and the microphone.

F. Chipset

Controls data flow among components.

G. IDE (Integrated Drive Electronics) cable

Transfers data from storage devices to the motherboard.

H. Disk drives

Stores data permanently (even after the computer is turned off). They may be any drives such as floppy disk drive, the CD-ROM/CD-RW, DVD-ROM/DVD+/-RW drive, and the hard disk drive.

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