Top Banner

Click here to load reader


Oct 01, 2015





DAVIET/ECE 1B/1408636

PRACTICAL NO. 1: FAMILIARIZATION WITH COMPUTER SYSTEMINTRODUCTION TO COMPUTER Fig.1.1 Computer systemComputer is an electronic device that is designed to work with Information. The term computer is derived from the Latin term computare, this means to calculate. Computer can not do anything without a Program. it represents the decimal numbers through a string of binary digits. The Word 'Computer usually refers to the Centre Processor Unit plus Internal memory.Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations. The basic components of a modern digital computer are: Input Device, Output Device, Central Processor. A Typical modern computer uses LSI Chips.

Charles Babbage is called the "Grand Father" of the computer. The First mechanical computer designed by Charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch cards.

Fig.1.2 Block Diagram of ComputerCharacteristics of computer Speed




Retrieving data and programs




DiligenceComponents A general purpose computer has four main components: thearithmetic logic unit(ALU), thecontrol unit, thememory, and the input and output devices (collectively termed I/O). These parts are interconnected bybusses, often made of groups ofwires.Inside each of these parts are thousands to trillions of smallelectrical circuitswhich can be turned off or on by means of anelectronic switch. Each circuit represents abit(binary digit) of information so that when the circuit is on it represents a "1", and when off it represents a "0" (in positive logic representation). The circuits are arranged inlogic gatesso that one or more of the circuits may control the state of one or more of the other circuits.

The control unit, ALU, registers, and basic I/O (and often other hardware closely linked with these) is collectively known as acentral processing unit(CPU). Early CPUs were composed of many separate components but since the mid-1970s CPUs have typically been constructed on a singleintegrated circuitcalled amicroprocessor.Arithmetic logic unit (ALU)The ALU is capable of performing two classes of operations: arithmetic and logic.

The set of arithmetic operations that a particular ALU supports may be limited to addition and subtraction, or might include multiplication, division,trigonometryfunctions such as sine, cosine, etc., andsquare roots. Some can only operate on whole numbers (integers) whilst others usepoint to representreal numbers, albeit with limited precision. However, any computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform. Therefore, any computer can be programmed to perform any arithmetic operationalthough it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and returnBoolean truth values(true or false) depending on whether one is equal to, greater than or less than the other ("is 64 greater than 65?"). The ALU can perform basics operations like addition, subtraction, multiplication, division, etc. and does logic operations like >,";