# Computer Studies/ICT/IT (All Classes)

## HISTORICAL DEVELOPMENT OF COMPUTING DEVICES

HISTORICAL DEVELOPMENT OF COMPUTING DEVICES The origin of computers dates back to when our fore fathers used their early calculating devices to count. For example Counting with fingers and toes: calculations were done by our fore fathers with their toes and fingers before the invention of computers. Counting with pebbles: when counting with fingers became […]

## Computer Hardware and Software

Definition of Computer hardware This refers to the physical units or components which make up the computer configuration. The term hardware refers to the tangible parts of a computer that can be seen and touched. Examples of hardware components Monitor Motherboard CPU( Central Processing Unit) RAM( Random Access Memory) Expansion Cards Power Supply Optical Disk

## Constituents Parts of a Computer System

A computer is a special multi-purpose electronic device (Machine) that is capable of receiving instruction (data), storing and processing it and giving a desire result as output accurately at an incredibly high speed. The computer as a system is made up of the following: 1.      Hardware 2.      Software   HARDWARE Refers to the physical units

## Logic Gate

These are gates that are formed from combination of two logic gates. There are two types of alternative logic gate: NAND GATE A NAND gate is the combination of an AND gate and NOT gate. It operates the same as an AND gate but the output will be opposite. Remember, the NOT gate does not

## Logic Gate

LOGIC EQUATIONS Aside representing the functioning of a logic gate with truth table and grammatical definition, the use of logic equations can be used not only to represent logic gates and circuits, but also with the usage of some theorems and equivalences, to reduce the number of terms involved, simplifying the equation. In logic equation

## Logic Circuit

LOGIC GATES A logic gate is an elementary building block of a digital circuit. Most Logic gates have two inputs and one output. At any given moment, every terminal is in one of the two binary condition low (0) or high (1). The logic gate of a terminal can, and generally change often, as the

## Differences between primary and secondary memory

Differences between primary and secondary memory Primary storage devices Secondary storage devices 1 These devices are temporary. These devices are permanent. 2 These devices are expensive. These devices are cheaper. 3 These devices are faster, therefore expensive. These devices connect via cables and are slow, therefore cheaper. 4 These devices have less storage capacity. These

## Types of Secondary Storage

SECONDARY MEMORY Secondary memory or storage is the non – volatile memory that stored externally from the computer. A secondary – storage medium is usually used for the storage of large amount of data or for permanent or long – time storage of data or programs. It is also used for storing backups. Secondary storage

## Memory Unit

Memory is the part of the computer that holds data and instructions for processing. It stores program and instructions or data for only as long as the program they pertain to is in operation.   TYPES OF MEMORY a.    Primary Memory b.   Secondary Memory   (a) PRIMARY MEMORY This is the memory that can be

## Central Processing Unit

The main objective of the CPU is to perform mathematical calculations on binary numbers; still there are other goals of using CPU as well. The CPU comprises many hardware components like motherboard and circuits. A central processing unit (CPU) is the hardware within a computer that carries out the instructions of a computer program by performing the basic arithmetical, logical, control, and input/output operations of the system.

## OVERVIEW OF COMPUTER HARDWARE

Computer Hardware This is the collection of physical elements that constitutes a computer system. Computer hardware refers to the physical parts or components of a computer such the monitor, mouse, keyboard, computer data storage, hard drive disk (HDD), system unit (graphic cards, sound cards, memory, motherboard and chips), etc. all of which are physical objects

## INTERNET

There are different internet or web browsers to browse the internet. Some of the most popular ones are: Internet Explorer, Netscape Navigator, Opera and Firefox, Nescape Navigator.   FEATURES IN A BROWER WINDOW IE has many different Parts, most of which you know e.g The Title bar, Status Bar, Menu Bar and standard tool bar;

## INTERNET

The internet is a collection of interconnected computer network around the world that provides a wealth of information on nearly any topic you can imagine. The world Wide Web, often simply called the web, is a subsystem of the internet.  DEFINITION OF INTERNET The internet is a worldwide network of computers that share information. Information

## BASIC PROGRAMMING II

BASIC PROGRAMS FIND SUQARE ROOT OF NUMBERS 10 REM FIND SUQARE ROOT OF NUMBERS 20 INPUT “ENTER FIRST NUMBER OF RANGE”; A 30 INPUT “ENTER LAST NUMBER OF RANGE”; B 40 FOR I = A TO B 50 PRINT “THE SUARE ROOT OF “; A; “IS “;SQR(A) 60 NEXT A 70 END   FIND SQUARE

## BASIC PROGRAMMING

BASIC has a number of built in functions that greatly extend its capability. These functions perform such varied task as taking the square root of a number, counting the number of characters in a string, and capitalizing letters. Functions associate with one or more values, called input, a single value called output.   NUMERIC FUNCTIONS:

## FLOW CHART

A flow chart helps in showing the sequence of different approaches in solving a problem. Flow chart is very concise in nature. It identifies steps needed in solving a problem and shows these steps with connecting lines and arrows to indicate the order in which the steps are performed.   FLOWCHARTING SYMBOLS

## ALGORITHM AND FLOW CHART

To make a computer do anything you have to write a computer program. To write a computer program you have to tell the computer, step by step exactly what you want it to do. An Algorithm can be defined as the set of rules and sequential steps that define how a particular problem can be

## PROGRAM DEVELOPMENT II

Step 1: Program Specification   Program development can be divided into several stages which are shown in the diagram below   Step 2: Program Design Step 6: Program Maintenance Step 4: Program Test Step 3: Program Code Step 5: Program Documentation  1.       Problem Definition This stage is the formal definition of task. It

## Program Development

An organized list of instructions that, when executed, causes the computer to behave in a predetermined manner is called a program. There are many programming languages –C, C++, Pascal, BASIC, FORTRAN, COBOL, and LISP are just few. These are high level programing languages. We also have low level language called assembly languages and machine language.

## SYSTEM DEVELOPMENT CYCLE II

I.            Preliminary Study Is the first stage of system development life cycle. This is the brief investigation of the system under consideration and gives a clear picture of what actually the physical system is. In practice, the initial system study involves the preparation of a ‘System Proposal’ which list the problem definition, objectives of