Section 01Systems Development1 01 Systems Development And Franchise Colleges By MANSHA NAWAZ.

Section 01 Systems Development 1

01 Systems Development

And Franchise Colleges

By MANSHA NAWAZ


Learning Aims• Objective

– to understand system development lifecycle – to understand the concept of a Systems

Analysis & Design

• Aims– outline the function of each system

development stage– outline Systems Analysis tasks– outline Systems Design tasks


What Is SAD, BSA or SD?

Developing Computer Systems !


Types of Computerised Systems

• Transaction Processing Systems (TPS)

• Real-Time Systems (RTS)

• Management Information Systems (MIS)

• Decision Support Systems (DSS)

• Knowledge Based Systems (KBS)

• Executive Information Systems (EIS)

• Office Automation Systems (OA)


Computer Systems in Organisations

Transaction Processing Systems

BankingSystems

EPOS Systems

Healthcare Systems

Insurance SystemsLeisure Industry



Real-Time Systems

Automated Production Control

Control SystemsSecurity Systems



Management Information Systems

0

20

40

60

80

100

1st

Qtr

2nd

Qtr

3rd

Qtr

4th

Qtr

East

West

North

Decision Support Systems

OfficeAutomationSystems

Knowledge Based Systems

Executive Information Systems


Problem Solving & Computers

Follows a setHuman of rules

Highly Highly non-programmed programmed

Transaction ExecutiveProcessing Information Systems Systems

Requires humaninterpretation


Who Develops Computer Systems?

• The Computer Industry– Software houses– Systems houses & integrators– Hardware vendors ..

• In House– D P Departments (or IT Services) ..– End Users? …

• Move towards Packaged Software


Developing Computer Systems

• SYSTEMS DEVELOPMENT– Strategy involved building & maintaining a computer

system through is ‘life cycle’

• THE LIFE CYCLE– A systems existence from ‘idea’ to ‘termination’

• STRUCTURED METHODOLOGY– Action Plan for Systems Development – Documentation– Uses abstract modelling ‘CASE tools & technique’


Forces on Systems Development

SystemsDevelopment

Legal

Require

ments

Users

CompanyPolitics

Ethical Issues

Technical Issues

ENVIRONMENT

Time

Development Approach


Systems Development

• Formalised approach to systems development by use of a STRUCTURED METHODOLOGY– Yourdon, Waterfall, SSADM, Prototyping,

Object Oriented, etc.

• Greater clarity of requirements and traceability through a SYSTEMS LIFE CYCLE

• Focus on business needs

• More user involvement

• Reduction in maintenance time and effort


Systems Life Cycle• All systems have a limited lifetime• Typical reasons for obsolescence

– business growth– new technology becomes available– changes in users’ requirements– changes in environment

• Typical system lifetime 4-10 years• Structured Methodologies are used to create a

system


What is Structured Methodology?• General statement

– Avison[82] ”a recommended series of steps and procedures to be followed in the course of developing an Information System”

• An underlying model– conceptual representation of the product

• A language– means of describing the product

• Defined & ordered steps– the process of creating the product

• Guidance for applying– procedures for conducting the process


• Yourdon

• WATERFALL• SSADM

• Prototyping

• Object Oriented

• etc

Structured Methodology


Yourdon

• The Analysis Models– The Essential Model

• The Environmental Model

• The Behavioural Model

– The User Implementation Model

• The Design Models– The Processor model– The Task Model– The Program Implementation Model

A STRUCTURED METHODOLOGY


Yourdon developed the standardisation of CASE tool & techniques.

• Model– process oriented

• Language– graphical, dfds etc.

• Steps– essential model etc.

• Guide– texts, courses, tools


Waterfall Life Cycle

May have iterations butthese are very costly

Systems Investigation

Systems Analysis

Systems Design

Systems Implementation

Review & Maintenance

Feasibility Study

Project Specification

“Waterfall” Approach



Systems Analysis & Design• Analysis is the problem

solving stage


Systems Analysis

Systems Design



Feasibility Study


Design is building upon the analysis to develop the selected solution


SSADM

• feasibility study module– stage 0, fast run through (RA) ?proceed?

• requirements analysis module– stage 1 traditional systems analysis– stage 2 specify possible business options

• requirements specification module– stage 3 detailed systems analysis



SSADM Contd.

• logical system specification module– stage 4 technical options– stage 5 user interface & further detail

• physical design module– stage 6 design with respect to options selected


PROTOTYPING

• Based on rapid development of refining a system over a period of time.

• Basic System built early in life cycle• Using automation, i.e.

– Program generators– 4GL languages– System development tools– Packaged (standard) modules

• But there can still be problems



Prototyping - amended lifecycle

Identify basicInformationRequirements

Develop Systemto fulfil basicRequirements

Experiment withbasic system inApplication area

Refine Prototypeto reflect knownRequirements

Success depends on available tools:

Application Packages

Program Generators

4GLs


Spiral Model

Risk analysis based on initial requirements

PlanningPlanning Risk analysisRisk analysis

Customer evaluationCustomer evaluation EngineeringEngineering

Risk analysis based on customer reaction

Go, no-go decision

Toward a completedsystem

Initial software prototype

Next prototype level

Engineered system

Customerevaluation

Planning basedon customercomments

Initial requirementsgathering and projectplanning



Object Oriented Lifecycle

• Different emphasis needed (OMG : Bennett et al)

Object Modelling

Life Cycle

Coordination and reuse

Strategic modelling

Analysis modelling

Design modelling

Implementation Mod.

Construction

Delivery

Full definition of the system



Methodology Summary

• Many lifecycle methodologies

• Systems are being developed faster

• Less documentation (is that a problem?)

• Four D,s– Decide, (Analyse), Design, Develop, Deploy


Problems of Software Development

• Software Crisis or Affliction– Schedule and cost estimates often grossly

inaccurate– Productivity has not kept pace with demand– Frequently poor quality systems are delivered– Existing systems are difficult to maintain



Some Recent Problem Projects• "Concerns about the reliability of data mean that the launch of the Government's troubled Criminal

Records Bureau (CRB) has been postponed until the Autumn… (Computer Weekly 7 June 2001)• "The roll out of a £319m PFI project aimed at speeding up the criminal justice system has been

postponed indefinitely amid spiralling costs and serious technical concerns…The cost of the contract has increased by £136m since it was signed in 1998" (Computer Weekly 28 June 2001)

• "DVLA savings disappear. EDS proposed 30% savings from £5m vehicle software but DVLA underestimated the technology challenge." (Computer Weekly 30 August 2001)

• "Financial services company Prudential Europe has terminated a £35m IT contract with Unisys…Prudential stands to lose about £10 million…not taking account the impact on business expansion plans…" (Computer Weekly 13 September 2001)

• Crams, the probation service case management system is to be dumped after six years of development at the cost of millions of pounds. (Computer Weekly 13 July 2000)

• "The UK treasury has abandoned hopes of recovering millions of pounds in compensation for delays in the new national insurance system because it needs to preserve the relationship with the system's developer, Anderson Consulting…a decision which illustrates the huge potential for outsourcer lock-in…" (Computing 4 April 2000)

• The MOD lost over £40 million pounds on two failed IT projects. In one case a system was abandoned without ever having worked properly due to 'software problems'. In another case the complexity of a pay system was underestimated at the outset and the project spiralled out of control. It was abandoned after £8.7 million had been spent. The public accounts committee reported that the MOD's attempts to develop bespoke systems were "ill-considered". (Computer Weekly 31 August 2000)

• "The police service is more than a year behind in delivering some of its key IT targets" (Computer Weekly 31 August 2000)

• Data from self-assessment tax returns submitted to the Inland Revenue through its Internet service has to be re-keyed into the main self-assessment computer system. (Computer Weekly 13 July 2000)


• Note the top three reasons for failure. These are three areas where structured methods might make claims of improvement. For instance:

• "The main [claim of structured methods] …is that they result in systems that more closely match the needs of users because user requirements have been more fully understood and communicated from the outset…" (Weaver, Lambrou Walkley, 1998, p4)

• "It is a basic principle of SSADM that the users have involvement in, and commitment to, the development of their system from a very early stage…" (Goodland and Slater, 1995, p3)

• In general it is true to say that the authors of books on structured methods offer little hard evidence to support their claims. No research, for instance, to show that the use of a structured method actually improves the understanding of user requirements. Of course it would be quite difficult to perform such research in practice, so the proponents of methods tend to fall back on more qualitative arguments to support their position. One argument runs like this: methods use diagrammatic techniques; these are easily understood by users and promote better communication with the users; this improved understanding and communication leads to a better definition of requirements. You might like to see if you can summarise, in a similar way, any of the other arguments made in defence of structured methods. How convincing do you find these kinds of argument? What counter arguments can you come up with?


Why things go wrong

Type of Failure Reason for Failure Comment

QualityProblems

ProductivityProblems

Wrong problem addressedSystem conflicts withbusiness strategy

Wider influences are neglectedOrganisational culturemay be ignored

Analysis carried out incorrectly

Project undertaken for wrongreason

Users change their mind

External events change theenvironment

Implementation is not feasible

Poor project control

Team poorly skilled orinadequately resourced

From Bennett et. al. (1999)

Technology pull orpolitical push

New legislation

May not be known untilproject has startedInexperienced projectmanager

Requirements drift


The impact of change

0102030405060708090

100

Definition Development Maintenance

Cost to change


Real World Situation I

• Structured systems development easy to understand– new practitioners &

customers

• divides large complicated process up into small easier bits– better to manage


Real World Situation II

• stages blurred • customer often wants to

see ‘real s/ware’– prototyping

• requirements frozen?– iterate back between the

stages

• less suited to newer programming

that’s the theory but what about the real world?


Towards Computerisation• What is needed to be done to move from position A to B?

A B

Paper Based Computer Based

?

• Increase Revenue– boost sales

• Avoid Costs– cheaper production or labour

• Improve Service– to achieve other two above

• acronym IRACISIRACIS

Why Computerise?


Role of Systems Analyst


SAD experience in the Real World• "What Does a Systems Analyst Really Do?", [On-line],

University of Missouri: School of Business Administration, USA.

• Available from:

http://www.umsl.edu/divisions/business/mis/system.htm

• [Accessed: 12/09/02].

http://www.umsl.edu/divisions/business/mis/systems.htm

http://www.umsl.edu/divisions/business/mis/systems.htm


You Use Analysis Every Day

• e.g. Expedition Scenario• The group are going on an overland journey to Borneo, a six week

expedition.• They have been sponsored by “Wicked” magazine who will pay

£5000 conditional on receiving two interim articles, for publication during the expedition, one major feature article at the end and a follow up three months later.

• They will need to take a portable computer, digital camera and mobile phone at the very least.

TASK:• What do you need to do in order to successfully complete the

project? How do you determine this?


Systems Analyst Skills• Systems Thinking

• Systems concepts / Applying systems thinking to Information Systems

• Organisational Knowledge• Processes / internal politics• Competitive & regulative environment / strategies & tactics

• Problem Identification/Analysis/Solving• Technical Skills

• hardware / software• publications / professional societies / courses & conferences

• Management Skills• resource management / project management• risk management / change management /humans

• Interpersonal Skills• communication skills / working alone & in teams• facilitating groups / managing expectations


Specialist Skills

• Systems Analysts used to do all these tasks• Computing is getter ever more complex• Beyond the capability of ONE person• Specialisms

– Business Analysts– Data Analysts– Networking..– Communications …WWW ..etc etc

• TEAM – GROUP OF PEOPLE SHARE WORK LOAD


“Systems Analysis is what the Systems Analyst Does” (Parkin,1987)

• Conducts feasibility studies (with alternatives)• Liases with users and determines requirements• Finds out facts important to the design of the proposed system• Determines human and computer procedures that will make up

the new system• Designs data storage (files) and interfaces• Writes program specifications• Tests programs and systems• Designs implementation procedures• Documents the system• Plans, monitors and controls the systems development• Reviews how successful the project was• Oversees maintenance of the system


Systems Analysis & Design• Analysis is the problem

solving stage


Systems Analysis

Systems Design



Feasibility Study


Design is building upon the analysis to develop the selected solution


Project Selection

Feasibility Study

SystemInvestigation

SystemAnalysis

SystemDesign

SystemImplementation

Review &Maintenance

“Construction builds the system in a series of iterations. Each iteration is a mini

project. You do analysis, design, coding, testing and integration for

the use cases assigned to each iteration.”

Fowler, 1997

“On the other hand,the disadvantage of any form of iterative life cycle is that the project team and/or the user may fall prey to the temptation of endless iteration.”

Yourdon, 1994


Need A Problem Solving ?Problem Solving is …..

• “….. the art of finding ways to get from where you are now to where you want to be (assuming you do not already know how).

• The ‘problem’, therefore, is the gap between the present situation and a more desirable one.”

(Nolan 1989)Is this Problem Solving?A B

?

PROJECT SPECIFICATION STAGE



The Mess! Problem Definition

Generate Ideas Gaining Acceptance

Data Gathering

Solution Finding

Identifying The Problem


• Having identified a problem area we need to produce a Project Specification

• Structured Systems Development : starting point to project work

Problem Definition


Project Specification is also referred to as a TERMS OF REFERENCE


PROJECT SPECIFICATION• PROJECT TITLE• AUTHOR• SUPERVISOR• PROPOSER• OBJECTIVES • AIMS• RESOURCES & CONSTRAINTS• SCHEDULE• Sample to review in tutorialSample to review in tutorial


FEASABILITY STAGE :

• A report which investigates and justifies the need for the development of a new system.

• Full investigation into existing system.

• An appraisal of the existing system, practices and procedures.

• Highlight weakness


Systems Analysis Stage

• Also referred to as requirements stage

• To ascertain the composition of a proposed system.

• Identify WHAT is needed.

• Find out what the customer wants the system to do and record as a Requirements List– interviews, documentation, questionnaires etc.


• To outline, sketch, plan and develop an improved system.

• Build a blueprint or model of the required system • Use of CASE tools (Context Diagram, Dataflow

Diagram, Data Dictionary)

• Produce a report : Analysis Specification.

• Must specify "What is needed."• and not "How is it to be achieved ?"


Design Stage• “Stating how a system will be constructed

without actually building it” Rumbaugh (1977)

• Produce a report : Design Specification. – how will system data be stored

• design database tables / data attributes

– how will the system perform any operations• design of algorithms, queries, reports, functions, etc

– hardware configuration options


• Identify HOW the "needs" in the analysis stage are to be achieved.

• Specify design of proposed system.• Use of CASE tools (Normalisation, ER Model,

Tables, Forms, Queries, Reports, etc )• Provide information in order to produce the system.• Sketch plans

– Outline– Detail– Written Specifications ….THEN– Actual construction

• Must specify “How it is to be achieved”• and not “What is needed ?"


When to Design?

• Alongside construction (just in time?)• Alongside Analysis (solutions to problems as we go

along – often only in outline)• After the analysis stage (Detailed design)• Or both – as in rapid development

• Logical and Physical design– Independence of the physical implementation


Implementation Stage

• Writing of code– Pascal, Cobol, C, Forth

• Building of tables, relationships & queries– MS Access, FoxPro, Ingres, SQL

• Testing the individual components– test plans and documented results

• Testing the complete system– test plans and documented results


Maintenance Stage

• Delivery of the system• Data Input • User Guides• Training of staff• Operation strategy...user procedures• Changeover from old to new• Maintenance...fine tuning & bug fixing• Upgrades


Read the Supplement on

Systems Development Life Cycle

Read the Example report on

British WebObject Management System


Summary• Know the stages involved in Systems

Development

• The use of Systems Methodologies such as the WATERFALL model

• The importance of Systems Analysis & Design.

• Know the difference between Analysis & Design Project Documentation requirements & standards

Section 01Systems Development1 01 Systems Development And Franchise Colleges By MANSHA NAWAZ.

Documents

systems development10

systems existence

systems development14

systems development9

systems development3

systems analysis tasks

systems design tasks

systems development11