Quiz with Explainations - Telemark University Collegehome.hit.no/~hansha/documents/subjects/IA4412/quizzes/Answers... · Questions 1. What is Software Requirements ? 2. Requirements

RequirementsAnalysis

Hans-PetterHalvorsen,M.Sc.

QuizwithExplainations

Questions1. WhatisSoftwareRequirements?2. Requirementsvs.Design– Whatisthemaindifference(s)?3. ListdifferenttypesofRequirements4. WhatisUserRequirements?5. WhatisSystemRequirements?6. WhatisFunctionalRequirements?7. WhatisNon-FunctionalRequirements?8. GivesomeExamplesofNon-FunctionalRequirements9. WhatisSRS?10. MentionsomeRequirementsAnalysisProblems/Challenges?

WhatisSoftwareRequirements?

RequirementsAnalysis

Design

Implementation

Testing

Maintenance

PlanningDeployment

SRS

SDD

STD

Code

InstallationGuides

UserGuides

GanttChart

withERDiagram,UMLDiagrams,CADDrawings

TestDocumentation

SoftwareRequirementsSpecifications

SoftwareDesignDocumentsSystemDocumentation

TestPlan

ProjectPlanning

End-UserDocumentation

SystemDocumentation

SoftwareTestDocumentation

SDPSoftwareDevelopment

Plan

GanttChart

TheSoftwareDevelopment

Lifecycle(SDLC)

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SoftwareRequirements

Requirementsforasoftwaresystemsetoutwhatthesystemshoulddoanddefineconstraintsonitsoperationandimplementation

Requirements:“Thestatementsthatdescribewhatthesoftwaresystemshouldbebutnothowitistobeconstructed.”RequirementsEngineering:“Asetofactivitiesrelatedtothedevelopmentandagreementofthefinalsetofrequirementspecifications.”StepsintheRequirementsEngineeringProcess:

WhyspendtimeonRequirementsAnalysis?

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SoftwareDevelopmentLifeCycle(SDLC)

Costperdefectsandchanges

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TaketheRequirementsAnalysisseriously!!

Requirementsvs.Design– Whatisthemaindifference(s)?

SoftwareRequirements&DesignRequirements(WHAT):• WHAT thesystemshoulddo• DescribewhatthesystemshoulddowithWordsand

Figures,etc.• SRS – SoftwareRequirementsSpecificationSoftwareDesign(HOW):• HOW itshoulddoit• Examples:GUIDesign,UML,ERdiagram,CAD,etc.• SDD – SoftwareDesignDocumentManydontseparateSRSandSDDdocuments,butincludeeverythinginaRequirementsdocument.Inpractice,requirementsanddesignareinseparable.

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3. ListdifferenttypesofRequirements

High-LevelRequirements

…

….

DetailedRequirements

…

…

SoftwareRequirements

TypicalwrittenbytheCustomers,ProjectManagement,etc.

TypicalwrittenbySoftwareArchitects,SoftwareDevelopers,etc.

High-LevelRequirements• WHATshouldthesystemdo?• Whoshouldusethesystem• Whatisthepurposewiththesystem?• Performance• Whatpartsshouldthesystemconsistsof• WhatPlatformsshouldbeused(PC,Tablet,Web?,...)• etc.

UseWordsandFiguresinordertodescribetheseRequirements

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UserRequirements

SystemRequirements

Requirements

FunctionalRequirements

Non-FunctionalRequirements

SoftwareRequirementsCategories

WhatisUserRequirements?

UserRequirements• Statementsinnaturallanguageplusdiagramsoftheservicesthesystemprovidesanditsoperationalconstraints.

• Writtenforcustomers.

16I.Sommerville,SoftwareEngineering:Pearson,2010.

WhatisSystemRequirements?

SystemRequirements• Astructureddocumentsettingoutdetaileddescriptionsofthesystem’sfunctions,servicesandoperationalconstraints.

• Defineswhatshouldbeimplementedsomaybepartofacontractbetweenclientandcontractor.

I.Sommerville,SoftwareEngineering:Pearson,2010.

Uservs.SystemRequirements


Examples:

1. The MHC-PMS shall generate monthly management reports showingthe cost of drugs prescribed by each clinic during that month.

1.1 On the last working day of each month, a summary of the drugsprescribed, their cost and the prescribing clinics shall be generated.1.2 The system shall automatically generate the report for printing after17.30 on the last working day of the month.1.3 A report shall be created for each clinic and shall list the individualdrug names, the total number of prescriptions, the number of dosesprescribed and the total cost of the prescribed drugs.1.4 If drugs are available in different dose units (e.g. 10mg, 20 mg, etc.)separate reports shall be created for each dose unit.1.5 Access to all cost reports shall be restricted to authorized users listedon a management access control list.

User requirement definition

System requirements specification

Uservs.SystemRequirements


Examples:

1. The MHC-PMS shall generate monthly management reports showingthe cost of drugs prescribed by each clinic during that month.

1.1 On the last working day of each month, a summary of the drugsprescribed, their cost and the prescribing clinics shall be generated.1.2 The system shall automatically generate the report for printing after17.30 on the last working day of the month.1.3 A report shall be created for each clinic and shall list the individualdrug names, the total number of prescriptions, the number of dosesprescribed and the total cost of the prescribed drugs.1.4 If drugs are available in different dose units (e.g. 10mg, 20 mg, etc.)separate reports shall be created for each dose unit.1.5 Access to all cost reports shall be restricted to authorized users listedon a management access control list.

User requirement definition

System requirements specification

WhatisFunctionalRequirements?

FunctionalRequirements• Describefunctionalityorsystemservices.• Dependonthetypeofsoftware,expectedusersandthetypeofsystemwherethesoftwareisused.

• Functionaluserrequirementsmaybehigh-levelstatementsofwhatthesystemshoulddo.

• Functionalsystemrequirementsshoulddescribethesystemservicesindetail.


WhatisNon-FunctionalRequirements?

Non-FunctionalRequirements• Thesedefinesystempropertiesandconstraintse.g.

reliability,responsetimeandstoragerequirements.ConstraintsareI/Odevicecapability,systemrepresentations,etc.

• ProcessrequirementsmayalsobespecifiedmandatingaparticularIDE,programminglanguageordevelopmentmethod.

• Non-functionalrequirementsmaybemorecriticalthanfunctionalrequirements.Ifthesearenotmet,thesystemmaybeuseless.


GivesomeExamplesofNon-FunctionalRequirements

Non-FunctionalRequirementsExamples

• ProductRequirement:Thesystemshallbeavailabletoallclinicsduringnormalworkinghours(Mon–Fri,0830–17.30).Downtimewithinnormalworkinghoursshallnotexceedfivesecondsinanyoneday.

• OrganizationalRequirement:Usersofthesystemshallauthenticatethemselvesusingtheirhealthauthorityidentitycard.

• Externalrequirement:ThesystemshallimplementpatientprivacyprovisionsassetoutinHStan-03-2006-priv.

WhatisSRS?

TheSoftwareRequirementsDocumentSoftwareRequirementsSpecifications(SRS)

• Thesoftwarerequirementsdocumentistheofficialstatementofwhatisrequiredofthesystemdevelopers.

• Shouldincludebothadefinitionofuserrequirementsandaspecificationofthesystemrequirements.

• ItisNOTadesigndocument.Asfaraspossible,itshouldsetofWHATthesystemshoulddoratherthanHOWitshoulddoit.


TheStructureoftheSRSDocument

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Chapter Description

Preface This should define the expected readership of the document and describe its version history, including a rationale for the creation of a new version and a summary of thechanges made in each version.

Introduction This should describe the need for the system. It should briefly describe the system’s functions and explain how it will work with other systems. It should also describe howthe system fits into the overall business or strategic objectives of theorganization commissioning the software.

Glossary This should define the technical terms used in the document. You should not make assumptions about the experience or expertise of the reader.

User requirements definition Here, you describe the services provided for the user. The nonfunctional system requirements should also be described in this section. This description may use naturallanguage, diagrams, or other notations that are understandable to customers. Product and process standards that must be followed should be specified.

System architecture This chapter should present a high-level overview of the anticipated system architecture, showing the distribution of functions across system modules. Architecturalcomponents that are reused should be highlighted.

System requirements specification This should describe the functional and nonfunctional requirements in more detail. If necessary, further detail may also be added to the nonfunctional requirements.Interfaces to other systems may be defined.

System models This might include graphical system models showing the relationships between the system components and the system and its environment. Examples of possiblemodels are object models, data-flow models, or semantic data models.

System evolution This should describe the fundamental assumptions on which the system is based, and any anticipated changes due to hardware evolution, changing user needs, and soon. This section is useful for system designers as it may help them avoid designdecisions that would constrain likely future changes to the system.

Appendices These should provide detailed, specific information that is related to the application being developed; for example, hardware and database descriptions. Hardwarerequirements define the minimal and optimal configurations for the system. Database requirements define the logical organization of the data used by the system and therelationships between data.

Index Several indexes to the document may be included. As well as a normal alphabetic index, there may be an index of diagrams, an index of functions, and so on.


Example1

TheStructureoftheSRSDocument

EssentialsofSoftwareEngineering”,FrankTsui;OrlandoKaram;BarbaraBernal,3ed.,Jones&BartlettLearning

A. SystemOverview(briefdescriptionofwhatthesoftaresystemwilldo)B. TechnicalRequirements(Functionalrequirement,Nonfunctional

requirements,User-interfacespecification,Usertaskflow,Input/outputandotherdataspecifications,Interfacespecificationstoothersystems)

C. AcceptanceCriteria/InteractionScenariosD. Validation/VerificationE. RequirementsConsiderations(Assumptionmadeaboutthesoftware,

Endusers,Existingsystems,Environment,Limitations)F. OtherInformation...

Example2

MentionsomeRequirementsAnalysisProblems/Challenges?

Problems/Challenges• Stakeholdersdon’tknowwhatthey

reallywant.• Stakeholdersexpressrequirementsin

theirownterms.• Differentstakeholdersmayhave

conflictingrequirements.• Organisationalandpoliticalfactorsmay

influencethesystemrequirements.• Therequirementschangeduringthe

analysisprocess.Newstakeholdersmayemergeandthebusinessenvironmentmaychange.


O.W

idder.(201

3).geek&

poke.Available:

http://geek-and

-poke.com

References• SoftwareDevelopment- APracticalApproach

Halvorsen,Hans-Petter,2015• EssentialsofSoftwareEngineering

FrankTsui;OrlandoKaram;BarbaraBernal,3ed.,Jones&BartlettLearning

• SoftwareEngineeringI.Sommerville,10ed.:Pearson,2015

• SoftwareEngineering.ModernApproachesE.J.Braude andM.E.Bernstein,2ed.:Wiley,2011.

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Hans-PetterHalvorsen,M.Sc.

UniversityCollegeofSoutheastNorwaywww.usn.no

E-mail:[email protected]:http://home.hit.no/~hansha/