Computer fundamentals Computer fundamentals Basic Computer Organization Basic

Computer fundamentals Computer fundamentals Basic Computer Organization

Basic Computer Organization Computer fundamentals Computer fundamentals • All the computer systems perform the following five basic operations, for converting row input data into information, which is useful to their users: » Inputting » Storing » Processing » Outputting » Controlling 2/4/2022 2

Basic Computer Organization (cont…) Computer fundamentals Computer fundamentals • These five units correspond to the five basic operations performed by all computers system. The functions of each of these units is described below: v v v 2/4/2022 Input unit Output Unit Storage Unit Arithmetic Logic Unit (ALU) Control Unit Central Processing Unit (CPU) 3

Basic Computer Organization (cont…) Computer fundamentals Computer fundamentals • Input Unit : In short the following functions are performed by an input unit: � It accepts the list of instructions and data from the outside world. � It converts these instructions and data in computer acceptable form � It supplies the converted instructions and data to the computer system for further processing. 2/4/2022 4

Basic Computer Organization (cont…) Computer fundamentals Computer fundamentals • Output Unit : – The job of an output unit is just the inverse of that of an input unit. In short, the following functions are performed by an output unit: u It accepts the results produced by the computer which are in coded form and hence cannot easily understood by us. u It converts these coded results to human acceptable form u It supplies the converted results to the outside world 2/4/2022 5

Basic Computer Organization (cont…) Computer fundamentals Computer fundamentals • Storage Unit: In short, the specific functions of the storage unit are to hold X All the data to be processed and the instructions required for processing (receive the input devices). X Intermediate results of processing X Final results of processing before these results are released to an output device. 2/4/2022 6

Basic Computer Organization (cont…) Computer fundamentals Computer fundamentals X The storage unit of all computers is comprised of the following two types of storage: X Primary storage X Secondary storage 2/4/2022 7

Basic Computer Organization (cont…) Computer fundamentals Computer fundamentals • Arithmetic Logic Unit (ALU): â The place where the actual execution of the instructions takes place during the processing operation. â All calculations are performed and all comparisons are made in the ALU â Data may thus move from primary storage to ALU and back again to storage many times before the processing is over. â After the completion of processing, the final results which are stored in the storage unit are released to an output device. 2/4/2022 8

Basic Computer Organization (cont…) Computer fundamentals Computer fundamentals • The type and number of arithmetic and logic operations that a computer can perform is determined by the engineering design of the ALU. • However almost all ALU’s are designed to performed the four basic arithmetic operations add, subtract, multiple, divide and logic operations or comparisons such as less than, equal to, or greater than. 2/4/2022 9

Control Unit Computer fundamentals Computer fundamentals a How does the input device know that it is time for it to feed data into the storage unit? a How does the ALU know what should be done with the data once they are received? a And how is it that only the final results are sent to the output device and not the intermediate results? 2/4/2022 10

Central Processing Unit (CPU) Computer fundamentals Computer fundamentals v The control unit (CU) and the arithmetic logic unit (ALU) of a computer system are jointly known as the Central Processing Unit (CPU). v The CPU is the brain of any computer system. v All major calculations and instructions are made inside the CPU and the CPU is also responsible for activating and controlling the operations of other units of a computer system. 2/4/2022 11

Basic Organization of a Computer System Computer fundamentals Computer fundamentals Storage Unit Program and Data Input Data Secondary Storage Output Data Information (Results) Primary Storage Control Unit Arithmetic Logic Unit Indicates flow of Instructions and Data Indicates the control Exercised by the control unit 2/4/2022 Central Processing Unit (C P U) 12

Basic organization of a computer system Computer fundamentals Computer fundamentals Program & data Input unit Storage unit Output unit Result Control unit CPU Arithmetic Logic Unit Figure: Basic organization of a computer system 2/4/2022 13

The system concept Computer fundamentals Computer fundamentals A system is a group of integrated parts that have the common purpose of achieving some objectives. So the following three characteristics are key to a system: Ê A system has more than one element Ê All the elements of a system are logically related. Ê All the elements of a system are controlled in such a way that the system goal is achieved. 2/4/2022 14