| INFORMATION SYSTEMS |
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Definition of a Computer
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A device capable of solving problems or manipulating data by accepting data, performorming prescribed operations (mathematical or logical) on the data, and supplying the results of these operations.
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Computer System
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The physical equipment and instructions, that is hardware and software used as a unit to process data. It includes the C.P.U, its operating system and the pheripheral equipment like printer, disc, drive, keyboard and programs.
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Data
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Raw facts and figures.
A formulized representation of facts or concepts suitable for communication, interpretation or processing by automatic means.
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Parts of a Computer
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The input unit fetches the data to be processed. The processing unit converts the data into meaningful information and the output unit displays the processed information to the user which may be in the form of the displayed unit or the storage unit of the computer.
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Input Unit: This is the unit through which human beings communicate with the computer and input data.
Eg: Keyboard, mouse, joy stick, scanner, digital camera, electronic musical keyboard etc.
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Processing Unit: (Central Processing Unit) The central processing unit of the computer consisits of 3 parts.
| 1- Control Unit |
| 2- Arithemetic and logical unit |
| 3- Memory unit |
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Processing: Any combination of arithematic operation and logical comparison. |
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Arithmetic Operations: -, +, *, /. |
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Logical Operations: <, >, <>, =, etc. |
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Output Unit: This is the unit through which the computer communicates with human beings.
Eg: Printers, Monitors, V.D.U, etc.
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Memory Unit: This is the unit which stores data, instructions and results of the data processing operation. This is also called as memory or immediate memory or primary memory or random memory.
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The Main Memory Has Some Serious Limitations
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1. It is highly volatile (the contents of it will be lost if the power goes off or the computer is switched off). |
2. It has limited storage capacity. |
3. It is very expensive. |
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Control Unit: This is a unit which controls, supervise and co-ordinates the operations of all the units in a computer. Therefore, this is called as supervisor unit. This is compared to the human nervous system.
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Arithmetic and logical unit (A.L.U): This is the unit which performs all the arithmetic and logical operations involved in a program.
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Units Used To Measure The Memory |
Bits - Binary Digits (1 and 0) |
1 Byte - 8 bits (to store 1 character) |
1 Kilobyte - (kb or KB) = 1024 Bytes |
1 Megabyte - (mb or MB) = 1024 kb |
1 Gigabyte - (gb or GB) = 1024 mb |
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