unit1-introductiontosoftwareengineering-230710065742-dc6f5a7d.pdf

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1. Introduction to
Software
Engineering
Prepared by Dr.T.Thendral
06.07.2023

2. Course Objectives:
The main objectives of this course are to:
1.To enhance the basics of Software
engineering methods and practices
2.To earn the techniques for developing
software systems
3.To understand the object orient
4.To understand software testing approaches
Prepared by Dr.T.Thendral
06.07.2023

3. On the successful completion of
the course,student will be able to:
Understandthebasicconceptsofsoftware
engineering
Applythesoftwareengineeringmodelsindeveloping
softwareapplication
Implementtheobjectorienteddesigninvarious
projects
Knowledgeonhowtodoasoftwareprojectwithin-
depthanalysis
ToinculcateknowledgeonSoftwareengineering
conceptsinturngivesaroadmaptodesignanew
softwareproject
Prepared by Dr.T.Thendral
06.07.2023

4. What is Software?
Softwareisasetofinstructionstoacquireinputsandto
manipulatethemtoproducethedesiredoutputintermsof
functionsandperformanceasdeterminedbytheuserof
thesoftware
Alsoincludeasetofdocuments,suchasthesoftware
manual,meantforuserstounderstandthesoftwaresystem
Prepared by Dr.T.Thendral
06.07.2023

5. Description of the Software
Asoftwareisdescribedbyitscapabilities.Thecapabilitiesrelateto
thefunctionsitexecutes,thefeaturesitprovidesandthefacilitiesit
offers.
EXAMPLE
SoftwarewrittenforSales-orderprocessingwouldhave
differentfunctionstoprocessdifferenttypesofsalesorderfrom
differentmarketsegments.
Thefeaturesforexample,wouldbetohandlemulti-currency
computing,updatingproduct,salesandTaxstatus.
Thefacilitiescouldbeprintingofsalesorders,emailtocustomers
andreportstothestoredepartmenttodispatchthegoods.
Prepared by Dr.T.Thendral
06.07.2023

6. Classes of Software
Softwareisclassifiedintotwoclasses:
GenericSoftware:
isdesignedforbroadcustomermarketwhoserequirementsarevery
common,fairlystableandwellunderstoodbythesoftwareengineer
CustomizedSoftware:
isdevelopedforacustomerwheredomain,environmentand
requirementsarebeinguniquetothatcustomerandcannotbesatisfied
bygenericproducts
Prepared by Dr.T.Thendral
06.07.2023

7. What is Good Software?
Softwarehasnumberofattributeswhichdecidewhetheritisagood
orbad.
Thedefinitionofagoodsoftwarechangeswiththepersonwho
evaluatesit.
Thesoftwareisrequiredbythecustomer,usedbytheendusersofan
organizationanddevelopedbysoftwareengineer
Eachonewillevaluatethedifferentattributesdifferentlyinorderto
decidewhetherthesoftwareisgood
Prepared by Dr.T.Thendral
06.07.2023

8. What are the attributes of good
software?
Thesoftwareshoulddelivertherequiredfunctionalityandperformanceto
theuserandshouldbemaintainable,dependableandusable.
•Maintainability
–Softwaremustevolvetomeetchangingneeds
Dependability
–Softwaremustbetrustworthy
Efficiency
–Softwareshouldnotmakewastefuluseofsystemresources
Usability
–Softwaremustbeusablebytheusersforwhichitwasdesigned
Prepared by Dr.T.Thendral
06.07.2023

9. Software -Characteristics
Software has a dual role. It is a product, but also a vehicle for delivering a
product.
Software is a logical rather than a physical system element.
Software has characteristics that differ considerably from those of hardware.
Software is developed or engineered, it is not manufactured in the
classical sense
Software doesn’t “wear out”
Most software is custom-built, rather than being assembled from
existing components.
Prepared by Dr.T.Thendral
06.07.2023

10. Changing nature of
software(Types)
SystemSoftware-Acollectionofprogramswrittentoserviceother
programsatsystemlevel.
Forexample,compiler,operatingsystems.
Real-timeSoftware-Programsthatmonitor/analyze/controlreal
worldeventsastheyoccur.
BusinessSoftware-Programsthataccess,analyzeandprocess
businessinformation.
EngineeringandScientificSoftware-Softwareusing“number
crunching”algorithmsfordifferentscienceandapplications.System
simulation,computer-aideddesign.
Prepared by Dr.T.Thendral
06.07.2023

11. Changing nature of
software(Types)
EmbeddedSoftware-:
Embeddedsoftwareresidesinread-onlymemoryandisusedto
controlproductsandsystemsfortheconsumerandindustrialmarkets.
Ithasverylimitedandesotericfunctionsandcontrolcapability.
ArtificialIntelligence(AI)Software:
ProgramsmakeuseofAItechniquesandmethodstosolvecomplex
problems.Activeareasareexpertsystems,patternrecognition,games
InternetSoftware:
Programsthatsupportinternetaccessesandapplications.Forexample,
searchengine,browser,e-commercesoftware,authoringtools.
Prepared by Dr.T.Thendral
06.07.2023

12. Software Engineering
“Asystematicapproachtotheanalysis,design,implementationand
maintenanceofsoftware.”
(TheFreeOn-LineDictionaryofComputing)
“Thesystematicapplicationoftoolsandtechniquesinthe
developmentofcomputer-basedapplications.”
(SueCongerinTheNewSoftwareEngineering)
“SoftwareEngineeringisaboutdesigninganddevelopinghigh-quality
software.”
(ShariLawrencePfleegerinSoftwareEngineering--TheProduction
ofQualitySoftware)
Prepared by Dr.T.Thendral
06.07.2023

13. What is Software Engineering?
Engineering:TheApplicationofSciencetotheSolutionofPractical
Problems
SoftwareEngineering:TheApplicationofCStoBuildingPracticalSoftware
Systems
Programming
–IndividualWritesCompleteProgram
–OnePerson,OneComputer
–Well-DefinedProblem
–Programming-in-the-Small
SoftwareEngineering
–IndividualsWriteProgramComponents
–TeamAssemblesCompleteProgram
–Programming-in-the-Large
Prepared by Dr.T.Thendral
06.07.2023

14. What is the difference between software engineering and
computer science?
Computer ScienceSoftware Engineering
is concerned with
Computersciencetheoriesarecurrentlyinsufficienttoactasacomplete
underpinningforsoftwareengineering,butitisafoundationforpracticalaspects
ofsoftwareengineering
theory
fundamentals
the practicalities of developing
delivering useful software
Prepared by Dr.T.Thendral
06.07.2023

15. What is Software Engineering?
Althoughhundredsofauthorshavedevelopedpersonaldefinitionsofsoftware
engineering,adefinitionproposedbyFritzBauerprovidesabasis:
“[Softwareengineeringis]theestablishmentanduseofsound
engineeringprinciplesinordertoobtaineconomicallysoftwarethatis
reliableandworksefficientlyonrealmachines.”
TheIEEE[IEE93]hasdevelopedamorecomprehensivedefinitionwhenit
states:
“SoftwareEngineering:(1)Theapplicationofasystematic,disciplined,quantifiableapproach
tothedevelopment,operationandmaintenanceofsoftware;thatis,theapplicationof
engineeringtosoftware.(2)Thestudyofapproachesasin(1).”Prepared by Dr.T.Thendral
06.07.2023

16. Software engineering is a layered
technology -Pressman’s view:
Software Engineering Layers
Prepared by Dr.T.Thendral
06.07.2023

17. What is Software Engineering?
Software methods:
Software engineering methods provide the technical “how to’s” for
building software.
Methods --> how to encompass a broad array of tasks:
-requirements analysis, design, coding, testing, and maintenance
Software engineering methods rely on a set of basic principles.
Prepared by Dr.T.Thendral
06.07.2023

18. Software methods
Prepared by Dr.T.Thendral
06.07.2023

19. What is Software Engineering?
Software Process:
Softwareengineeringprocessisthegluethatholds:
-technologytogether
-enablesrationalandtimelydevelopmentofcomputersoftware
Softwareengineeringprocessisaframeworkofasetofkeyprocess
areas
Itformsabasisfor:
-projectmanagement,budgetandschedulecontrol
-applicationsoftechnicalmethods
-productqualitycontrol
Prepared by Dr.T.Thendral
06.07.2023

20. Software Process
Prepared by Dr.T.Thendral
06.07.2023

21. What is Software Engineering?
Software Tools:
-programs provide automated or semi-automated support for the
process and methods
-programs support engineers to perform their tasks in a systematic
and/or automatic manner
Prepared by Dr.T.Thendral
06.07.2023

22. Why Software Engineering?
Objectives:
-Identifynewproblemsandsolutionsin
softwareproduction
-Studynewsystematicmethods,principles,
approachesforsystemanalysis,design,
implementation,testingandmaintenance.
-Providenewwaystocontrol,manage,and
monitorsoftwareprocess
-Buildnewsoftwaretoolsandenvironmentto
supportsoftwareengineering
Prepared by Dr.T.Thendral
06.07.2023

23. Why Software Engineering?
Major Goals:
-To increase software productivityand quality
-To effectively control software scheduleand planning
-To reduce the cost of software development
-To meet the customers’ needs and requirements
-To enhance the conduction of software engineering
process
-To improve the current software engineering practice
-To support the engineers’ activities in a systematic and
efficient manner
Prepared by Dr.T.Thendral
06.07.2023

24. A Process Framework
Prepared by Dr.T.Thendral
06.07.2023

25. Process Framework Activities
Communication
Planning
Modeling
Construction
Deployment
Prepared by Dr.T.Thendral
06.07.2023

26. Umbrella Activities
Software Project Tracking & Control
Risk Management
Formal Technical Reviews
Software Configuration Management
Reusability Management
Prepared by Dr.T.Thendral
06.07.2023

27. PROCESS
MODELS
Prepared by Dr.T.Thendral
06.07.2023

28. SDLC Process Model
SDLC –Software Development Life Cycle
Process model is a framework that describes
the activities,actions,tasks,milestones,and
work products performed at each stage of a
software development project that leads to a
high quality software
Prepared by Dr.T.Thendral
06.07.2023

29. Life cycle models
Waterfall model
Incremental process models
–Incremental model
–RAD model
Evolutionary Process Models
–Prototyping model
–Spiral model
Object oriented process model
Prepared by Dr.T.Thendral
06.07.2023

30. WATERFALL MODEL
a.k.as Linear life cycle model orclassic life cycle model
Prepared by Dr.T.Thendral
06.07.2023

31. WATERFALL MODEL
Prepared by Dr.T.Thendral
06.07.2023

32. WATERFALL MODEL
Project initiation & requirement gathering
–What is the Problem to Solve?
–What Does Customer Need/Want?
–Interactions Between SE and Customer
–Identify and Document System Requirements
–Generate User Manuals and Test Plans
•Planning
–Prioritize the requirements
–Plan the process
Prepared by Dr.T.Thendral
06.07.2023

33. WATERFALL MODEL
Analysis and design
–How is the Problem to be Solved?
–High-Level Design
–Determine Components/Modules
–Transition to Detailed Design
–Detail Functionality of Components/Modules
Coding and Testing
–Writing Code to Meet Component/Module Design Specifications
–Individual Test Modules in Isolation
–Integration of Components/Modules into Subsystems
–Integration of Subsystems into Final Program
Prepared by Dr.T.Thendral
06.07.2023

34. WATERFALL MODEL
Deployment
–System Delivered to Customer/Market
–Bug Fixes and Version Releases Over Time
Strengths
Easy to understand, easy to use
Provides structure to inexperienced staff
Milestones are well understood
Sets requirements stability
Good for management control (plan, staff, track)
Works well when quality is more important than cost or schedule
Prepared by Dr.T.Thendral
06.07.2023

35. Waterfall Drawbacks
All projects cannot follow linear process
All requirements must be known upfront
Few business systems have stable requirements
The customer must have patience
Aworkingversionoftheprogramwillnotbe
availableuntillateintheprojecttime-span
Leads to ‘blocking states’
Inappropriate to changes
Prepared by Dr.T.Thendral
06.07.2023

36. When to use the Waterfall Model
Requirements are very well known
Product definition is stable
Technology is understood
New version of an existing product
Porting an existing product to a new platform
Prepared by Dr.T.Thendral
06.07.2023