1. COMPUTER MAINTENANCE REPAIR & TROUBLESHOOTING Powered by DeSiaMore1

2. DATA ABOUT DATA Our PC's are data processors. PC's function is simple: to process data, and the processing is done electronically inside the CPU and between the other components. That sounds simple, but what are data, and how are they processed electronically in a PC? That is the subject of these pages. Analog data The signals, which we send each other to communicate, are data. Our daily data have many forms: sound, letters, numbers, and other characters (handwritten or printed), photos, graphics, film. All these data are in their nature analog, which means that they are varied in their type. In this form, they are unusable in a PC. The PC can only process concise, simple data formats. Such data can be processed very effectively. Powered by DeSiaMore2

3. Digital data The PC is an electric unit. Therefore, it can only deal with data, which are associated with electricity. That is accomplished using electric switches, which are either off or on. You can compare with regular household switches. If the switch if off, the PC reads numeral 0. If it is on, it is read as numeral one. See the illustration below: We have that the Pc appears capable of handling data,if it can receive them as 0`s and 1`s.This data format is called digital.If we translate our daily data from their analog format to digital format,they will appear as chain of 0`s and 1`s then the PC can handle them. cont.... Powered by DeSiaMore3

4. DIGITAL DATA Powered by DeSiaMore4

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6. Bits Each 0 or 1 is called a bit. Bit is an abbreviation of the expression Binary digit. It is called binary, since it is derived from the binary number system: Powered by DeSiaMore6

7. The binary number system The binary number system is made up of digits, just like our common decimal system (10 digit system). But, while the decimal system uses digits 0 through 9, the binary system only uses digits 0 and 1. Powered by DeSiaMore7

8. The binary number system The binary number system is made up of digits, just like our common decimal system (10 digit system). But, while the decimal system uses digits 0 through 9, the binary system only uses digits 0 and 1. Powered by DeSiaMore8

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10. 1kilo-Byte = 1,024 byte (KB)APPROX.. 1,000 bytes MEASUREMENT-RELATED TERMINOLOGY 1mega-Byte = 1,048,576 byte (MB) APPR.. 1,000,000 bytes 1giga-Byte = 1,024 byte (GB) APPR.. 1,000,000,000 bytes 1tera-Byte = 1,024 byte (TB) APP.. 1,000,000,000,000 bytes (storage capacity elements)‏ Powered by DeSiaMore10

11. Hertz a unit of frequency measurement. It is synonymous with cycle per second, and it is used to describe the speed of a computer microprocessor. Megahertz (Mhz)‏ one million cycle persecond.This is a common measurement of speed of a processing chip. Gigahertz (GHz) one billion cycle per second.This is a common measurement of the speed of processing chip. Powered by DeSiaMore11

12. PC's user data, which are always digitized. But there are many different kinds of data in the PC. You can differentiate between 2 fundamental types of data: Program code, which are data, that allow the PC to function. User data, like text, graphics, sound. The fact is, that the CPU must have instructions to function. An instruction is a string of data, of 0's and 1's. The CPU is designed to recognize these instructions, which arrive together with the user input data to be processed Powered by DeSiaMore12

13. The program code is thus a collection of instructions, which are executed one by one, when the program runs. Each time you click the mouse, or hit a key on the keyboard, instructions are sent from your software (program) to the CPU,telling it what to do next User data are those data, which tells the software how to respond. The letters, illustrations, home pages, etc., which you produce, are created with appropriate software. Powered by DeSiaMore13

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