Third Generation Computer Languages

A program is a list of instructions that performs a particular task. Assembly programs were very long, this made it difficult to maintain programs written in Assembly. In the late 1950 Computer Scientists came up with high level computer languages which were closer to English and Mathematics. High Level languages are relatively easy for people to learn and to program computers. Fig 4.2, shows examples of four programs written in diffe rent high level programming languages which display the message “Hello World” on the computer screen. High...

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Introduction to Programming

Languages In Sri Lanka people use three languages Sinhala, Tamil and English. The purpose of a language is to allow people to communicate. If we want to communicate with a computer it would be ideal if you could use a language like English. Unfortunately computers at present are not intelligent enough to understand human languages. Because of this computer scientists have developed computer friendly languages. These computer languages could be learnt relatively easily by people. Using such a computer language you can communicate with a computer....

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Problems in Systems Development

It is evident by now, system development is a complex process. There are many areas where things can go wrong which may result in project failure. As per our initial discussion, the system development methodologies (such as SDLC) were proposed to provide some structure and formalism to system development process in order to ensure that valid systems are developed and to minimise the possibility of failure. Although, following a methodology does not guarantee success, it provides a mechanism to minimise failures and detect problems early in the...

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Systems Development Life Cycle

In Systems Development Life Cycle (SDLC) model, the development process is divided into a set of well-defined steps or phases as follows: Systems Investigation System Analysis and Requirements Definition Systems Design Software Development Testing Implementation Maintenance The SDLC is a development process that is best suited for projects where the requirements can be clearly defined. SDLC encourages top-down problem solving. That is, designers must first define the problem to be solved and then use an ordered set of steps to reach a solution....

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Information Systems Development

By now, we have gained an understanding of what information systems are and also seen their importance within an organisation. In this section, we discuss how information systems are developed. Developing information systems is a complex process (especially large-scale information systems). There have been many attempts in developing information systems that have failed to meet their objectives. Hence, information system development has been extensively studied and many approaches are proposed for information system development. We will study...

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What is object oriented programming ?

This question is a little difficult to answer because the computer industry has a fascination for terminologies and catch words. Not long ago words like “artificial intelligence”, ‘’gui” and “net surfing” were used as if they were to offer a path to heavens. The same overuse seems to be happening to the phrase “object oriented” Since it has been proven that object-oriented techniques offer a way to write better programs, every body seems to be slipping the label “object oriented” on their software products. So it is important for us to understand...

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Information System Types

As per our previous discussion, different levels of management require different types of information for their decision-making process. There are different types of information systems available geared towards different user needs. We can broadly classify some of the basic types of information systems as follows: Transaction Processing Systems Management Information Systems Decision Support Systems Executive Information Systems Expert Systems The following figure illustrates the focus areas of the different information system. The different...

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Types of Information Systems

Organisational Structure Traditionally, organisations have a hierarchical structure: the strategic level, the tactical level and the operational level. Levels in a traditional organisation The strategic level includes the top-level management in an organisation such as the chairman, board of directors etc. They make corporate goals and strategic decisions for an organisation. The top-level management typically makes strategic decisions. These decisions are typically unstructured in nature. Let us consider our example of the bank. The...

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What is an Information System?

An information system (IS) can be defined as an arrangement of people, data, processes, and interfaces that interact to support and improve day-to-day operations in an organisation as well as support the problem-solving and decision-making needs of management and users. Let us look at this definition in detail. An interface is the means by which two or more entities interact with each other in a system. For instance, in a school, a student may request for a “Character Certificate” by filling a pre-defined form and submitting it to the Registrar....

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Information Systems

In this section, we will learn concepts that lead us to understand what information systems are and its importance in an organisation. We will learn what data and information is, the role that information plays in problem solving and decisionmaking, define information system and also look at manual and computer-basedinformation systems. Data versus Information Firstly, let us revisit the concept of data and information. Data are raw facts pertinent to a system. In our example of a school, data can be names of students, teachers, subjects,...

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System Types

Systems can be classified into different types based on their characteristics. The following table illustrates the different system types and their primary characteristics. System Types and Primary Characteristics A single system can belong to many different system types based on their characteristics. Let us revisit our example of the school (viewed as a system). Is the school a simple or a complex system? Is the school an open or a closed system? Is the school a stable or a dynamic system? Is the school an adaptive or a nonadaptive system?...

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Elements of a System

Let us learn some new terms about systems. A system usually interacts with the external world or environment. The system boundary separates the system from its environment. A system’s boundary tells us what is inside and what is outside the system. A school (viewed as a system) illustrating the system boundary Let us consider our example of a school and identify the system boundary. In the above example, the system boundary clearly illustrates the components inside the school (that is, principal, teachers, students etc.) and components...

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Information systems

What is a system? A system is a collection on interrelated components that work together to perform a specific task or achieve a goal. In a system, the different components are connected with each other and they are interdependent. Each component is a subsystem of the original system and carries out a part of the system task. For example, the human body represents a complete natural system. Our human body contains complex muscle, bone, respiratory, digestive and circulatory subsystems, each providing a specific part of the system task.Let...

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Introduction to Information Technology

Usage and importance of IT There is a genera belief that Information Technology (IT) is about computers. However, this is not true. Information Technology (IT) is about computers. Information and knowledge utilizing such computers and communication networks. Information Technology (IT) has enabled people indifferent parts of the world to exchange information freely and with ease. In effect, IT makes us realize how small the world, we live in, is as it removes physical constraints such as distance between people in exchanging information. With...

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