adsi 1 - introduction
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Analysis and Design of Information Systems - Fathul Wahid 1
Introduction
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Some terms (1)
Method= a special form of procedure adopted inany branch of mental activity...a way of doinganything, especially according to a defined and
regular planModel= an abstraction or representation of partof the real world
Tool= any instrument of manual operation...anything with which some operation isperformed
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Some terms (2)
Technique= manner of artistic executionor performance in relation to formal orpractical details... the mechanical or formal
part of an art
Methodology= the science of method... atreatise or dissertation on method
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Methodology (per Avison & Fitzgerald)
a collection of procedures, techniques, tools,and documentation aids
to help system developers implement a new
information systemand consisting of phases and sub-phases
to guide system developers in choosingtechniques for each stage
and in planning, managing, controlling, andevaluating systems projects
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More terms
Process= A series of actions or tasksperformed in order to do, make or achievesomething.- e.g. the software development
processInformation System Development
Approach (ISDA)= A class ofmethodologies which share thefundamental concepts and principles forISD
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Global Information Age
... Everyone has to understand that if you do
not have the ability to use computertechnology in the 21st century, you will be as
competitively disadvantaged as if youcouldnt read at the turn of the last century...
--Investors Business Daily, 28 Sept 1995, p. A8
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Paradigm Shift:Open Systems in an Open World
New Geo-Political Context open, volatile, global, unpredictable
New Business Environment
changing markets, competition, rules, requirements
The New Enterprise information-based, networked, open organization
New IT Goals strategic technology, workgroups, value chain
New Technology Paradigm open, user-centered, network computing
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What People Are Really Asking for?
Its 1994. Welcome to the world of
wireless, multimegabit, rightsized, group-enabled, GUI-based, object-oriented, user-
empowered, decentralized, multimedia,massively parallel, totally open, mission-critical, almost-impossible-to-cost-justify
computing.-- Computerworld, December 27, 1993, p. 1
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A Process of Constant Change
New or modified
system is introduced
Application
environment
changes and
needs evolve
Users ask for
modifications
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How Well Have We Done?
PlanAnalyzeDesign
ImplementSupport
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What Have We Seen?
Increase in number and complexity ofsystems
And many unsuccessful systems
late
over budget
expensive to maintain
not what users wanted
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The CHAOS report from Standish Group
http://www.standishgroup.com/
US :$250 billion each year on SD-175000 projects
Average cost per project for large companies
$2322000, medium $1331000 and small$434000
Success 16.2%
Challenged 52.7%canceled 31.1%
average cost overrun 189% time overrun222%
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Pointing the Finger(Computerworld, 5/2/94)
Schedules go over budget and time because ofrequirements creep
Top reasons for requirements creep are:
Poor initial requirements definition (44%) New applications unfamiliar to users (36%)
Projects take so long that things change (28%)
Poor management of expectations (22%)
Failure to involve users in early stages (19%)
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Why the Failures?
complex applications
no user orientation
no attention to organizational environment
overly optimistic on time, cost, & operational cost
no intermediate review
lack of communication between users and
developers
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Search for a Silver Bullet
Only a silver bullet can kill a werewolf
We have searched for the silver bullet to
magically kill the monsters of missedschedules, overgrown budgets, and flawedsoftware
What are some of these silver bullets ?
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No Silver Bullet (Brooks, 1986)
Essence, the difficulties inherent in thenature of software
complexity, conformity, changeability,
invisibility
Accidents, difficulties that happen to existtoday but are not inherent
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Historical Perspective
1945-1965: Fortran, COBOL, Lisp, Algolcome into widespread use; IBM installs thirdgeneration of computers
1968: first NATO Conference on SoftwareEngineering, to confront developmentdifficulties
early 1970s: structured programming
mid 1970s: structured design; computer-aided documentation
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History - continued
late 1970s: structured analysis
late 1970s: data modeling
early 1980s: CASE tools; prototyping
mid 1980s: information engineering;Joint Application Development
late 1980s: Rapid Application Development
early 1990s: object-oriented development
late 1990s :?
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Dealing with the Software Crisis
concept of software engineering -- applying anengineering-like discipline to the process ofbuilding software systems
software life cycle -- applying the manufacturingconcept of a product life cycle
structured techniques
combining technical procedures withmanagement techniques
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Systems DevelopmentMethodology
need for systematic approach
understanding basic concepts & principles
and using appropriate tools & techniques
applied within organizational and managerialframework
applied consistently to successive system
development projects
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Systems
A ubiquitous word
But what exactly does the word mean?
What is an example of a system?What is it that makes something asystem?
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The Five Building Blocks
People
Data
ActivitiesNetworks
Technology
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Different Users...Different Systems...
TPS: Transaction Processing System
MIS: Management Information System
DSS: Decision Support System
EIS: Executive Information System
ES: Expert System
OAS: Office Automation System
GSS/Groupware: Group Support System
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Systems Are Diverse !
project size
degree of structure
type of technologypeople involved
organizational characteristics
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History via Survey Results(from varied sources)
1986: 10% of North American IS groups usestructured techniques in disciplined way
1987: 69% use structured approaches
1991: 65% of organisations with a methoddevelop it in-house
1992: 45% of IS managers are satisfied withtheir method; 25% describe their method asunknown
1992: 69% use SDLC to develop systems
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More on Methodology
Not just a recipe
But should have an underlying
philosophy, e.g, humanistic
scientific
pragmatic
automation-oriented
What is valued? What is emphasized?