Introduction to Information System Development.

Chapter 1Introduction to Information System Development

Developing Tyre Swings

System Development

Computer-based IS

IS that uses computer and communication technology to perform tasks

Basic component: Hardware Software Database Telecommunication Procedures People

Hardware

Physical component of computer system

System unit and motherboard are used to support and tie other components together

Consists of: Input device▪ Capture and translate data into a form that

can be processed and used by other parts of computer▪ Eg: keyboard, pointing device, bar code

scanner

Computer is composed of the CPU and internal memory▪ CPU is the chip that performs the instructions

received from software▪ Internal memory/Random Access Memory is a

temporary memory that hold software instruction and information for CPU▪ To permanently store info and recall them,

information need to be store in secondary storage device/external memory

Output device▪ Provide copies of data and information on

paper, video screen, etc. Modems▪ Input or output device that allow a computer

to transfer data between each other.

Software

Set of instructions Eg: computer code that hardware

devices carry out to process info Software is fundamental to computer Database software is a software that

allows you to arrange, modify and extract data from a database to create info

Telecommunication & Network

Telecommunication is a vital computer based tool to help communicate information to people in other location

Computer network through the use of communication technology can share resources such as storage database and processing power

Can send and receive information through network

People

Integral part of Information System Includes management and end user Manager use information to make

decisions End user supply data to Information

System and receive info from Information System

Procedure

A series of steps undertaken in a prescribed manner to accomplish a certain job

Human activities requiring people to interact with other components of IS

Can be written in form of manual or documentation such as diagram

When procedures are embodied in computer program, they are considered part of Information Technology component

Developing Information System

System development lifecycle is a series of recommended steps or phases designed as guideline as to what you should do and when you should do it

Actual number of phases and the name given to each phase differs from one organisation to another

It is simplified by combining some of the phases

The phases have a defined product or deliverable

Deliverables can be used to monitor productivity and quality of activities performed

Phases may have more than one deliverable

Phases of System Development Life Cycle

SDLC use to organize activities needed to build a system

Assist management by providing reports on project status and keeping track of resource need

Consist of:1. System planning

i. Prior to developing Information System, long term and short term planning must be done to prevent poor analysis and design of new system

ii. Preliminary investigation is a brief study of the problem.

iii. Output of this step is the project goal, scope and boundary and the terms of reference of the project

iv. May include any restrictions such as part of existing system which cannot be changed, etc

v. Also include rough idea of resource requirement of next phases

vi. The objective of IS project mgt is to deliver a system that is acceptable to users and develop within time and budget

vii. IS project mgt is the process of planning, scheduling and controlling the activities during the SDL

2. System analysisi. Is the detail understanding of

important features of system under investigation

ii. Include finding out how the existing system works, problems and the user requirement of the new system

iii. Determining accurate user information needs and system requirements is important because the design of new system will be based on these determined requirement

3. System designi. Information need and system requirement in

system analysis are studied in more detailii. Can be divided into general and detail

system design▪ At the end of general system design, we will know

what we need to develop and may include what software to use

▪ Detail system design/physical system design is the ext of general design.

▪ During this design, input, output, interface, database, network, programme and control are defined and documented

4. System construction and implementationi. During system construction, the individual

system components are builtii. New programs and changes to existing

program are written and testediii. During implementation, the component built

during construction are put into operational use

iv. After the new system is completed and working, post implementation review is performed to evaluate the new system and suggest minor changes to be made

5. System maintenancei. To eliminate errors in the systemii. Implies that there is continuous

improvement of the new system implemented

Structured Dev Vs Object Oriented Dev

Structured Development Employs a variety of diagrams and

documentations for describing the requirement of IS

Eg: DFD, ERD and structured diagram Involve users in developing the IS User need to participate in the analysis and

design process as they are the people who use the system

Emphasis on logical system design Major critics: takes too long and require too much

documentations

Object-Oriented Development System developer first define the object

needed in the new or revised IS If object already exist, they are reused. If

not they will select an existing object that is closed to the one needed and then modify the existing object as necessary

Unified Modeling Language (UML) is an object oriented programming language use to describe IS

IS Project Team

End user People who directly interact with IS Supply data to IS and receive info from IS

Business analyst Analyses the business aspects and issues

surrounding the IS identifying how they will provide business value in creating, developing and designing new procedure and policies together with the system analyst

Will have business exp and some type of professional training

System analyst Focuses in IS issue surrounding the system by

identifying how IT can improve business processes, design the IS and the new business processes and ensure compliance with std

Responsible for planning, undertaking and coordinating overall dev activities

Likely to have significant training in analysis and design, programming and even areas of business

Infrastructure analyst Identify and implement infrastructure

changes on technical issues involve in how the system will interact with the org’s infrastructure – Eg: hardware, software, database, network

Likely has significant training and exp in database administration, networking and etc

Change management analyst Focuses on people and mgt issues surrounding

the IS installation The roles include ensuring that adequate

documentation and support is available to user, provide user training on the new system and developing strategies to overcome resistance to change

Likely have significant training and exp in organizational behavior in general and change mgt in particular

Project manager Oversees the system dev project from

beginning to end, manages the project team, dev and monitors project plan, assign resources and act as primary point of contract for the entire systems project

Likely have exp in project mgt and likely has work for many years as system analyst