COMPUTER MAINTENANCE REPAIR & TROUBLESHOOTING Powered by DeSiaMore1

COMPUTER MAINTENANCE REPAIR & TROUBLESHOOTING

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DATAABOUT DATAOur PC's are data processors. PC's function is simple: to process data, and the processing is done electronically insidethe CPU and between the other components. That sounds simple, but what are data, and how are they processedelectronically in a PC? That is the subject of these pages.

Analog dataThe 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 processconcise, simple data formats. Such data can be processed very effectively.


Digital data

The PC is an electric unit. Therefore, it can only deal with data, which are associated with electricity. That isaccomplished using electric switches, which are either off or on. You can compare with regular household switches. Ifthe 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.

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DIGITAL DATA



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:


The binary number systemThe 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.


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.



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)


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.


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


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 DeSiaMore 13


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