Www.sims.monash.edu.au information systems information systems development development methodologies IMS9300 IS/IM FUNDAMENTALS

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information systems information systems developmentdevelopment methodologies

IMS9300 IS/IM FUNDAMENTALS

www.sims.monash.edu.au/subjects/ims93002

This lecture’s objectives

• Understand what we mean when we talk about information systems:– system concepts and components

– understand the need for information systems

– introduction to roles and tasks associated with building information systems


A word about “Systems thinking”

The application of formal systems theory and concepts to systems problem solving (the SIMS approach):

• Helps us understand how systems are organised and how they work

• Simplifies inherent system complexity• Useful to apply systems thinking to

understanding of business organisations’ activities and their information systems


Information Systems

• The nature, purpose and makeup of computerised Information Systems

• What you should know about Information Systems if you intend to develop, manage or work with them


a “system”

• An assembly of components that interact in an organised way to accomplish goals

• e.g. river systems, nervous system, public transport system, legal system, education system, water supply system, elevator system, information system.


What makes a something a system

• a boundary – a beginning and an end, parameters

• a purpose – a goal, meet a perceived need

• an environment – all external things which interact with the system

• interfaces – points of interaction with) the rest of the world

• inputs, processes, outputs – takes things from the environment, does something with them, and returns things to the environment

• feedback – uses self-report to modify its operation

• constraints – subject to things which stop it running free

• subsystems – contains servant systems within itself


What makes a something a system 2

• boundary – order to after sales service; mouse to printer

• purpose – supply customers; report

• environment – air temperature; users

• interface – instructions on a Met Ticket machine; document in MS Word

• input – button press at vending machine;

• process – • output – cash from ATM;

• feedback – thermostat; “Press OK to continue”

• constraints – heart pacemaker; privacy laws

• subsystems – Supermarket weighing machine; system clock


System types

• Simple ------------------------------------ Complex

vending machine; Metropolitan Transport• Open --------------------------------------- Closed

air conditioner; watch• Stable -------------------------------------- Dynamic

elevator; nervous system• Permanent ------------------------------- Temporary

government; Concert Management


The “right” information

• Useful information is essential if an organisation is to achieve its goals:

accurate complete economical

flexible reliable relevant

simple timely verifiable

accessible secure

• An information system is designed to produce such information


Business organisations are complex systems

• Business organisations organise their activities and work practices into various systems because: – many different tasks must be done

– different data are needed for different tasks

– a single task is often done many times

– complex processes must be coordinated

– the environment changes constantly


How canInformation Systems help ?

• Efficiency, reliability, economy, control• An Information System is a formal arrangement

of people, data, processes• Integrated to

– manage complexity – support and improve business operations– Support and improve the problem-solving and

decision-making activities of managers. • It transforms Data into Information

(Why are computers not mentioned?)


Computer-Based Information Systems

• Information systems may or may not involve the use of computers

• Computers significantly expand the potential of information systems because they:– are more reliable processors than humans– are faster than humans, and “tireless”– are easily replicated – are much more productive– have enormous memory capacity


Information System Components

Information system components include:• people - need the information, build the

system, operate it and use it

• data and information -the raw material which the system is set up to manage and distribute

• machines (usually computers) - help manage and process the data and information

• procedures - define how the information is to be input/stored/processed/ etc.

– formal – specified, perpetual, expected

– informal – unspecified, trivial, one-off


Functions of an Information System

Any information system performs four main functions:

• data input - capturing information

• data storage/retrieval - keeping information

• data processing - transforming information

• data output - displaying/presenting information


Benefits of Information Systems

A good information system ensures:-

• the right information• to the right degree of accuracy• when it is required• in the right format/layout• to the right people• in the most efficient way possible

(Have you had to deal with an information system which did not work well? Which of these things was not present in that system?)


The Complexity of Information Systems

Even small information systems can be very complex:

• many components (lots of information)• much interaction between components• systems within systems (subsystems)• the intangibility of information (hard to define)• the subjective nature of information

(interpretation)• differing needs of different system users


Computer-based information systems

• “unique” situations: customer enquiry system; ticket booking

• generic business applications: payroll systems; inventory systems

Types of information systems e.g.:– transaction processing systems, – decision support systems,– expert systems, – executive information systems,– geographical information systems


Building Information Systems

Activities involved in building computer-based information systems are:-

• identifying business information problems

• analysing and describing information needs

• designing solutions to meet those needs

• acquiring/building new systems

• implementing new systems


System building players

• System owner/s• System user/s• Project leader (manager)• Systems analyst/s• Systems designer/s• Systems builder/s • IT vendor/s and consultant/s


Building Information Systems:The Role of the Systems Analyst

• to understand the system’s information needs

– what information is needed?

– for whom?

– in what form?

– when?• to describe the system’s information flows and

processes• to identify problems, opportunities, constraints• to suggest possible system solutions


Business Information System Problems and Opportunities

• The need to build new information systems or change existing ones comes about because:

– there are problems in the way in which existing systems operate

or

– changes in circumstances create opportunities to improve things by doing them differently

or

– new functions or activities are to be undertaken


Business Information Processing Problems

• Information problems occur when an organisation’s systems fail to meet its information and processing needs adequately. Some causes:– changing information needs– business expansion– cost pressures– competitive pressures– new business activities– inefficiencies

• Information processing problems can occur at any stage of the information processing cycle


Characteristics

• complex -

the number and variety of components and their interactions

• non-standard -

many organisations have similar needs, but rarely are these identical

solutions must be customised for specific circumstances

• unstructured -

problems cannot easily be broken down into clearly-defined components with easily-identified connections between them

Business Information Processing Problems


Approaches to information systems development

• early computer information systems development focused on automating functional tasks eg. TPS. Technician/ programmer as oracle

• systems developer specialists oversee large new development projects).

• as computer use became more widespread, maintenance and upgrade of existing applications has unexpected and undesirable effects

• these problems led to awareness of the need for an overall accepted, standardised approach to system development (METHODOLOGIES)


Some Approaches to Systems Development

• Traditional Waterfall SDLC- formal approach which partitions development into distinct phases

• Prototyping - an iterative process of building on a scaled-down solution, rapidly

• Application Packages - purchase commercially available software

• Joint Application Development (JAD) - a proscribed workshop approach in which users and builders work intensively together over a short period (days) to specify requirements and design a system

• RAD - rapid application development using computerised techniques to specify system designs and build systems quickly


Which Approach to Use?

• Depends on:– nature of the problem

– complexity of the problem

– degree of standardisation of the problem

– experience in solving this kind of problem

– extent to which the problem can be structured into small self-contained parts


Systems Development Lifecycle (SDLC)

The concept of the systems development life cycle (SDLC) is an attempt at organizing and standardising system building. It provides:

• a systematic and orderly approach to solving business information and processing problems

• a means of managing, directing, monitoring and controlling the process of system building, including:

– a description of the process - steps to be followed

– deliverables - reports/programs/documentation/etc

– milestones - dates of completion of steps or deliverables


The Systems Development Lifecycle (SDLC): the waterfall model

• it has several phases that define the progress of the development process

• it is often adapted to suit the organisational, human and technical needs of organisations and system development projects

• there are many variants of the SDLC. We will consider the traditional waterfall model as an example

• perfectly suited to large-scale, “new” development, but a template for all scientific approaches to system development


Benefits of SDLC

• breaks the problem-solving process into manageable steps

• identifies and defines everything which needs to be done, and how it should be done

• identifies the resources needed in each step

• identifies who will do each activity and when they will do it

• provides a basis for project planning


Principles ofSystem Development

• get the owners and users involved

• use a problem-solving approach

• establish phases and activities

• establish standards for consistent development and documentation

• justify systems as capital investments

• don’t be afraid to cancel or revise project scope

• divide and conquer

• design systems for growth and change


Systems Development Phases

Analysis

Design

Implementation

Review

Maintenance

Quality

Documentation

Ethics

Project Management

Analysts RoleInitiation


Quality

• Quality is defined as fitness for purpose and concerns both process and product.

• Error detection and correction in analysis and design is much cheaper than after the system is implemented.

• Achieving quality requires that organisational structures, responsibilities, procedures, processes and resources for implementing quality management are in place.


Project management

– Select systems development methodology

– Plan the project tasks

– Estimate the resources and time required to complete individual phases of the project

– Staff the project team

– Organise and schedule the project effort(tasks/time/ people/technical resources) and therefore cost

– Control the project development:

direct the team, monitor progress, replan, restaff, reallocate resources


Documentation

– Various types of documentation must be produced throughout the SDLC

– The data dictionary plays an important role during and after systems development:

– A repository for information about and definitions of all “objects” identified during development

– It supports and is maintained throughout the system lifecycle

– It provides an important source for system documentation


Professional ethics

• Australian Computer Society (ACS)

Code of Ethics for IT professionals• your reputation• your client's interests• confidentiality

– the client’s own and their competitors'

• impartiality• honesty


Systems Development:The systems developer’s skills

Systems developers require many different skills during the SDLC. Some of these are:

• Interpersonal skills - to communicate effectively, facilitate groups, work in teams, manage expectations and change, deal with organisational politics

• Analytical skills - to identify problems and determine solutions

• Business knowledge - understanding of business systems• Technical skills and knowledge - to use the technology,

and understand its potential and limitations • Management skills - to manage resources, projects, risk,

and organisational change


Who does Systems Development?

• The organisation’s information technology department

(in-house development)• End-user computing - development of systems by

end-users with minimal assistance • Outsourcing - contracting development to external

providers• IT consultants• Often a combination of the above


There is no such thing as a 'correct’,'standard' development lifecycle approach to system development , because all information and processingproblems are different and need differentsystem development approaches.

Summary


References

• WHITTEN, J.L., BENTLEY, L.D. and DITTMAN, K.C. (2001) 5th ed., Systems Analysis and Design Methods, Irwin/McGraw-HilI, New York, NY. Chapter 1 and 3

• HOFFER, J.A., GEORGE, J.F. and VALACICH (1999) 2nd ed., Modern Systems Analysis and Design, Benjamin/Cummings, Massachusetts. Chapter 1

• TURBAN,E., RAINER, R.K.Jr. & POTTER, R.E. (2003) 2ND ed. Introduction to Information Systems. John Wiley International Section 14

Documents

Www.sims.monash.edu.au information systems information systems development development methodologies IMS9300 IS/IM FUNDAMENTALS