SYSTEM DEVELOPMENT-Understanding the Problem

IPT- 2009 Miss O’Grady

WHY ARE NEW INFORMATION SYSTEMS DEVELOPED?

Either an existing system no longer meets the needs of its users or new needs are identified that could be met by an information

system.

System Development Life System Development Life CycleCycle

1. Understanding the Problem

2. Planning

3. Designing

4. Implementing

5. Testing, Evaluating and Maintaining

Refer to Page 24 of Textbook- IPT Samuel DavisComplete Group Task with a partner (5-10mins)

Complete Group Tasks on pg 25 in your

textbook

UNDERSTANDING THE PROBLEM

Understanding the ProblemUnderstanding the Problem

The primary aim of this first stage of the SDLC is to determine the purpose and requirements of a new system.

•System Analyst

System Analyst

A person who analyses

systems, determines

requirements and designs new

information systems.

Requirements ReportRequirements Report

• The purpose of the system

• An analysis of the existing system

• Definition of the Requirements

What needs to be done?What needs to be done?• Interview/Survey Users of the Existing

System

• Interview/Survey Participants in the Existing System

• Requirements Prototypes

• Define the Requirements for a New System

Interview/Survey Users of the Existing Interview/Survey Users of the Existing SystemSystem

• The users being the people who utilise the information created by the system. Example : Customers

• The results of surveys are often more useful for highlighting existing problems rather than revealing new needs and ideas that are not currently being addressed.

• New needs & ideas are more likely to reveal themselves through interviews.

Complete Group Task on page 28 which asks you to have a look at the survey on page 29.

Interview/Survey Participants of the Interview/Survey Participants of the Existing SystemExisting System

• Participants will have an understanding of the part of the system they primarily interact.

• They are able to identify problems and often have ideas in regard to solving these problems.

• System analysts often perform analysis with participants. Writes down each step performed to complete a task, time as well as inputs and outputs.

Complete Group Task on page 31

•Complete Group Task on page 33- ‘List the tasks performed by Fred during hiswork with Pet Buddies so far. Identify the skills Fred possesses to complete thesetasks’.

• Explaining the sequence of activities to Iris and Tom.

• Create customer satisfaction survey.• Organise and analyse results of the

survey.• Telephoning a sample of customers.• Develop a list of user needs and

requirements.• Task analysis of Tom and Iris.• Various ongoing discussions with Iris and

Tom.• Creation of context diagrams and DFDs

of existing system.• Delivering presentation and

question/answer session with experts.

Requirements Requirements PrototypesPrototypes

A working model of an information system, built in order to understand

the requirements of the system.

Screen Generators

Reporting Generators

Refer to page 38-39

Pet Buddies Requirements Report Introduction Part 1

CONTEXT DIAGRAMS- Shows the data that enters and leaves an

information system.

DATA FLOW DIAGRAMS- Shows how data moves through a system.

External Entity

Process Data StoreD

ata Flow

EXERCISETextbook- Page 43,44 & 45Read page 43 & 44 and complete questions on page 45 on a piece of paper with your name at the top and hand in for marking.

Testing Evaluating and Maintaining

• By Melad, Andrew, Brenton, Michael, Matthew

Testing to Ensure system meets requirements

Tests involve:• Volume Data• Simulated

Data• Live data

Volume Data

• tests a system with large amounts of data

• it ensures the system will function under large data loads

• TDG (test data generator) reads definition of data base and makes up data

Simulated Data

• For testing the system under simulated conditions

• For testing system performance under different scenarios

• Software is used to make the simulated data

• One example is mercury interactive load runner

Live Data

• it tests the system using actual data the fully operational system would use

• it ensures a system operates in real situations

• it begins straight after implementation

Trialing and using the operational manual

• the operation manual describes procedures participants must follow when using the new system

• there’s a trial period and usually results to modifications to the manual

• there usually step by step instructions

• operational manuals are constantly upgraded

Ongoing evaluation to monitor performance`

Technical performance monitoringAims to evaluate the continuing achievement of

the systems evolving requirementsSome old requirements may go down in priority.

Other new requirements will emerge and existing ones will change.

Ongoing evaluation aims to verify that all requirements continue to be met and identify any

changes

• Financial performance monitoring

• Includes analyzing the system’s economic feasibility.

• Largely about evaluating the accuracy of the economic predictions made in the feasibility study.

• Aim is to evaluate the extent which the new system achieving its economic goals

• Ongoing evaluation to review the effect on users, participants and people within the environment

• Surveys the effectiveness of the new system

• Decreased privacy including perception of decreased privacy

• Privacy act 1988- Info system containing personal info must legally explain:

• Explain why personal info is collected• Provide individuals with access to their records• Correct inaccurate info• Describe to individuals the purpose of holding info• Describe info held and how its managed• Changes in the type and nature of employment• New system will alter work performance by people.

Positive or negative effects

• Health and safety concerns• Workers exposed to health and safety problems• Employers responsible to minimise risks and set up

procedure for identifying and take course of action on OHS issues

• Makes sure the environment is ergonomic. Furniture, lighting, noise level, airing/ circulation etc.

• Little or no sense of accomplishment• Workers need a sense of accomplishment• Tasks must have purpose, a start and end point.• Variety needed to min. boredom• Deskilling• Info system performs processes were once performed by

participants• May result in job loss or retrain to use new software• Loss of social contact• Becoming a common issue• Working at home is less social as well as working long

hours

• Maintaining the system to ensure it continues to meet requirements

• Systems need this to ensure it keeps meeting requirements. Involves

• Regular maintenance & repairs when faults occur• Some tasks include:• Maintaining a hardware and software inventory• Perform backups of they systems data and ensure they are

in a safe location• Protect against viruses by ensuring virus software is used

and updated• Ensure illegal software is not installed and all software is

licensed• Maintain hardware• Install replacement hardware and software• Setup network access• Monitoring uses of peripheral devices• Purchasing and replacing faulty hardware• Ensure new users receive training

• Modifying parts of the system where problems are identified

• Problems identified during any of the tasks require modifications to the system

• New requirements will emerge over the life of the system that will require modifications to be made

• For each new modification the SDLC commences again

• Necessary to ensure modification works correctly with all parts of the system and ensure all documentation is updated.