1. How a Computer Processes Data

2. With today’s technology a little knowledge about what’s inside a computer can make you a more effective user and help you select the right computer for the job you need it to do. In this lesson you will learn how the CPU processes data and turns it into information. And you will learn about some of the basic components contained on the computer’s motherboard.

3. Computer System Components We use computers for all kinds of tasks—to predict weather, to fly airplanes, to control traffic lights, to play games, to access the Internet, to send e-mail, and so on. You might wonder how a machine can do so many things. To understand what a computer really does takes a degree in computer engineering. But most of us don’t need that level of understanding. Instead, we need an overview for a basic understanding.

4. Just about all computers, regardless of size, take raw data and change it into information you can use. The process involves input, process, output, and storage (IPOS).

5. For example: You input data with some type of input device The computer processes it to turn it into information. You output the information to some type of output device. You store it for later retrieval.

6. Input, output, and processing devices grouped together represent a computer system. In this lesson, we look at the components that the computer uses to process data. These components are contained within the system case.

7. System Components The PC system case is the metal and plastic case that houses the main system components of the computer. Central to all of this is the motherboard or system board that mounts into the case. The motherboard is a circuit board that contains many integral components. A circuit board is simply a thin plate or board that contains electronic components.

8. Some of the most important of these components are as follows: The central processing unit Memory Basic controllers Expansion ports and expansion slots

9. The Central Processing Unit The central processing unit (CPU), also called the microprocessor, the processor or central processor, is the brains of the computer. The CPU is housed on a tiny silicon chip. This chip contains millions of switches and pathways that help your computer make important decisions. The switches control the flow of the electricity as it travels across the miles of pathways.

10. The CPU knows which switches to turn on and which to turn off because it receives its instructions from computer programs. Programs are a set of special instructions written by programmers that control the activities of the computer. Programs are also known as software.

11. The Arithmetic/Logic Unit The arithmetic/logic unit (ALU) performs arithmetic computations and logical operations. The arithmetic operations include addition, subtraction, multiplication, and division.

12. The logical operations involve comparisons. This is simply asking the computer to determine if two numbers are equal or if one number is greater than or less than another number.

13. These may seem like simple operations. However, by combining these operations, the ALU can execute complex tasks. For example, your video game uses arithmetic operations and comparisons to determine what displays on your screen.

14. The Control Unit The control unit is the boss, so to speak, and coordinates all of the CPU’s activities. Using programming instructions, it controls the flow of information through the processor by controlling what happens inside the processor.

15. We communicate with the computer through programming languages. You may have heard of programming languages called BASIC, COBOL, C++, or Visual Basic. The computer does not understand our language. It only understands machine language, or binary, which is ones and zeros. This is where the control unit takes over.

16. The control unit reads and interprets the program instruction and changes the instruction into machine language. Recall that earlier we discussed the CPU and pathways and switches. It is through these pathways and the turning on and off of switches that the CPU represents the ones and zeros. When electricity is present, it represents a one. The absence of electricity represents a zero. After changing the instructions into machine language, the control unit then sends out the necessary messages to execute the instructions.

17. Memory Memory is also found on the motherboard. Sometimes understanding memory can be confusing because it can mean different things to different people. The easiest way to understand memory is to think of it as “short term” or “long term.” When you want to store a file or information permanently, you use secondary storage devices such as the computer’s hard disk drive or a floppy disk. You might think of this as long term.

18. Random Access Memory