TOPIC 3 INTRODUCTION TO INFORMATION TECHNOLOGY

TOPIC THREE;
This topic was mainly concerned with information. it was a very interesting topic as we learnt a great deal of detail on the different type of information systems used in organisations.
Firstly, we defined  information systems as a set of components that is input, processing, mechanisms, out put and feedback to display information.which drives us to CBIS which is a computer based information system which serves the following functions

1. Supporting business operation ( done by TPS, OMS,)
2. Management support system (systems used MIS, DSS, ESS)

That is why companies need both operational, tactical and strategic information in decision making and their respective system for managing them at the different levels.
We also know that the information systems has some components which includes;

•Computer Hardware: tangible part of computer

   a) Input device

b) Processing device

c) Output device

d) Storage device

The intangible parts of the CBIS is the software which manage the operation of the computer. They are also known as programs, divided into three categories and they include:

•System Software

•Application Software

•Programming Language

The last part of the CBIS is the people interacting with it.

Which brought us to the types of information systems which are;

Transaction Processing System (TPS),
Decision Support System (DSS),
Management Support System (MIS) and
Executive Support System (ESS).
In this topic we went a head to discuss all the above information systems in details as follows

TRANSACTION PROCESSING SYSTEM (TPS)
This is  a computerized system which records all the transaction from all the departments in an organisation and keep them into a database. eg the CMS, and Library loan system in AIU.
The following features describe the transaction processing system;
One TPS for each department, used by operational personnel and supervisors, collect, process and store transaction information, its the backbone of an organisation's IS.
We also know that information can be entered ito a TPS ;
Manually by having a person to enter the data using free hands, Automated by capturing the data using bar-code reader or scanner, and Fully automated where the system does entry automatically of any transaction or product needed.
Finally, the methods of transaction processing in TPS are Online processing which involves immediate processing and feedback, and Batch processing where transactions are collected and then processed collectively at a later time.

MANAGEMENT INFORMATION SYSTEM (MIS)
This is the information system used by middle level managers to produce reports and also known as the management reporting system (MRS). The source of information for MIS is the transaction processing system only (TPS).

DECISION SUPPORT SYSTEM (DSS).
This is the information system used by middle level managers to make decision. The role of DSS is to provide information to aid managers with decision making. The source of information for this system are both internal and external. the internal sources are the TPS and  MIS while  the external sources are the customers, users and other stake holders.

EXECUTIVE SUPPORT SYSTEM (ESS)
This is the information system used by the top level managers to make strategic decision for an organisation. It provides the information to aid strategic managers in making future plans. The source of information in ESS/EIS are both internal and external. Internally the information for the system are got from the TPS, MIS and DSS while externally the information are got from the users, customers, share holders, competitors and other stake holders.

SYSTEM METHODOLOGY
The concept of information system development (ISD) can be defined as the stages involved in an information system development project. It is the process of defining, designing, testing, and implementing a new software application or program.
While ISD METHODOLOGIES is a collection of procedures, techniques, tools and documentation aids which will help the systems developers in their efforts to implement a new information system. The development of a new system is triggered when there is a problem with the existing system and desire to introduce new system. This process involves the project manager, stake holders, users, programmer, system analyst and  support personnel.
THE STEPS IN ISD PLANNING
Strategic Plan
Develop Objectives
Identify IS Project
Analyze resource
Set Schedule and deadlines
Develop IS
The following are the types of ISD Methodologies;
Gane and Sarsons (STRADIS), Information engineering, Jackson system development, Prototyping iterative approach, Structured approach (SDLC), Soft system methodology, Ethics etc.
The reason why the above methodologies are needed in an organisation are;
 Ensuring system development process is systematic
Allowing system development to be managed to ensure high quality assurance
To achieve effectiveness and efficiency in organization
To meet user requirement in the new system.
Most of these roles are done by the system analyst which include;

• Collecting/ examining/analyzing data and information.
• overseeing the implementation of a new system
• presenting proposals to clients
• drawing up specific proposals for modified or replacement systems

CLASSICAL SDLC

It is the oldest and most known methodology based on a set of generic life cycle stages to guide developers from an initiating through maintenance of the completed systems. SDLC is defined as a whole process of developing system or software to meet certain requirements. It is  a comprehensive method. It covers many activities starts from understanding why the system should be built, studying the project feasibility, analyzing problems, choosing the system design and architecture, implementing and testing it, up to delivering the system as product to the user.

SDLC is characterized by a chronological approach, the user get to see the system late in the development and tight control.

The stages for developing a system using SDLC are;

System Investigation

System Analysis

System Design

System Implementation

System Maintenance and review

The advantages of this method is that it is good for developing any kind of information system, developing large, expensive, and complicated systems and when the project has clear objectives and solution.

PROTOTYPING

This is a system development methodology that uses a trial-and-error approach for discovering how a system should operate. It is done;

BEFORE THE BEGINNING to show proof of concept to senior management

IN THE BEGINNING to gather initial user requirements

IN THE MIDDLE STAGES to confirm system specifications AND pre-train users or to create a marketing demo.

Prototyping is an iterative process and its main objective is to enhance quality of the requirement specification. The process of prototyping involve; Determining requirements, developing a prototype, reviewing prototype with users, implementing and using the system. It is most useful when;

• Prototype model should be used when the desired system needs to have a lot of interaction with the end users.
• Typically suitable for online system, with full screen terminal activities 
• The system does not require large amounts of algorithmic process
• System where the emphasis is on screen layout, report format, data entry and etc (record management system, ad hoc retrieval).

GANE AND SARSONS (STRADIS)

STRADIS stands for Structured Analysis, Design and Implementation of Information Systems.

Chris Gane and Trish Sarson introduced their ideas on systems analysis and design in the late 1970's. 

The methodology remains today as one of the most popular techniques for structured analysis and design of systems.

The Gane & Sarson method is based on the building of a logical model of the system, using graphical techniques to enable users, analysts, and designers to get a clear and common picture of the system and how its parts fit together to meet the user's needs.

The focus of analysis in the Gane and Sarson method is the Data Flow diagram, which is used to describe the processes of the system, and how the processes transform data.

The stages in STRADIS include; Detail Study, Designing alternatives, Physical design and implementating the system.