In as long as matics 43 Introduction to Software EngineeringLecture 2 Duplication of cour

In as long as matics 43 Introduction to Software EngineeringLecture 2 Duplication of cour www.phwiki.com

In as long as matics 43 Introduction to Software EngineeringLecture 2 Duplication of cour

Baier, Agnieszka, Managing Editor has reference to this Academic Journal, PHwiki organized this Journal In as long as matics 43 Introduction to Software EngineeringLecture 2 Duplication of course material as long as any commercial purpose without the explicit written permission of the professor is prohibited.Today’s lectureProgramming versus software engineeringComplexity, con as long as mity, changeability, intangibilitySoftware architectureExamplesSome slides adopted in addition to adopted from “Software Architecture: Foundations, Theory, & Practice” by Taylor, Medvidovic, in addition to DashofyToday’s lectureProgramming versus software engineeringComplexity, con as long as mity, changeability, intangibilitySoftware architectureExamples

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Essential characteristicsSoftware engineering concerns the development of large programsThe central theme is mastering complexityThe efficiency with which software is developed is of crucial importanceSoftware evolvesRegular cooperation between people is an integral part of programming-in-the-largeThe software has to support its users effectivelySoftware engineering is a field in which members of one culture create artifacts on behalf of members of another cultureSoftware engineering is a balancing actProgramming versus software engineeringProgrammingSoftware engineeringFrom programming to software engineeringPeoplewho else would do the workrange from novice to very experiencedProcessesto organize in addition to manage the ef as long as ts of individualsrange from in as long as mal to very as long as malToolsto support the people in addition to the processesrange from simple to very advanced

PeopleThe single most important factor in the success/failure of a productScarce resourcequalitysuitabilitycostMany different kinds of peoplemanagersprogrammerstechnical writersProcessesEssential to achieve a quality productScarce resourcequalitysuitabilitycostMany different kinds of processesbug trackingchange approvalquality assuranceToolsNeeded to support people in addition to processesScarce resourcequalitysuitabilitycostMany different kinds of toolsdrawinganalysisproject managementsource code management

Today’s lectureProgramming versus software engineeringComplexity, con as long as mity, changeability, intangibilitySoftware architectureExample 1: LinuxExample 2: iRADSExample 3: HADOOPArchitectural stylesPrinciples of software engineeringBrooks – Mythical Man MonthAccidental versus essential difficultiesAccidental difficultiespeople shortagenot using the right toolswrong design choice Essential difficultiescomplexitycon as long as mitychangeabilityintangibilityComplexityNo two software parts are alikeif they are, they are abstracted away into oneComplexity grows non-linearly with sizee.g., it is impossible to enumerate all states of a programexcept perhaps “toy” programs

Con as long as mitySoftware is required to con as long as m to itsoperating environmenthardwareOften “last kid on block”Perceived as most con as long as mableChangeabilityChange originates with new applications, users, machines, st in addition to ards, lawshardware problemsSoftware is viewed as infinitely malleableIntangibilitySoftware is not embedded in spaceoften no constraining physical lawsNo obvious representatione.g., familiar geometric shapes

Drastic consequencesDeceased patientsx-ray machine delivered very high doses because of a timing problem in its control softwareCrashed planessoftware prevented pilots from per as long as ming emergency maneuverssoftware had similar codes as long as different airportsDecreased national securityNSA computers down as long as four days due to a “software problem”Peter Neumann’s Risks Digest: http://catless.ncl.ac.uk/RisksToday’s lectureProgramming versus software engineeringComplexity, con as long as mity, changeability, intangibilitySoftware architectureExamplesSoftware architectureRequirementsCode

Software architectureRequirementsCodeAn analogy to building architecturesWe all live in them(We think) We know how they are builtrequirementsdesign (blueprints)constructionuseThis is similar (though not identical) to how we build softwareParallelsDesign be as long as e buildSatisfaction of customers’ needsSpecialization of laborMultiple perspectives of the final productIntermediate points where plans in addition to progress are reviewed

The architectA distinctive role in addition to character in a projectVery broad trainingAmasses in addition to leverages extensive experienceA keen sense of aestheticsDeep underst in addition to ing of the domainproperties of structures, materials, in addition to environmentsneeds of customersLimitations of analogySoftware serves a much broader range of purposesWe know a lot about buildings, much less about softwareThe nature of software is different from that of building architectureSoftware is much more malleable than physical materialsSoftware is a machine; a building is notBut still very real power of architectureGiving preeminence to architecture offers the potential as long as intellectual controlconceptual integrityeffective basis as long as knowledge reuserealizing experience, designs, in addition to codeeffective project communicationmanagement of a set of variant systemsLimited-term focus on architecture will not yield significant benefits!

Baier, Agnieszka Meteoritics & Planetary Science Managing Editor www.phwiki.com

Defining software architectureA software system’s architecture is the set of principal design decisions about the systemSoftware architecture is the blueprint as long as a software system’s construction in addition to evolutionDesign decisions encompass every facet of the system under developmentstructurebehaviorinteractionnon-functional properties“Principal”“Principal” implies a degree of importance that grants a design decision “architectural status”it implies that not all design decisions are architecturalthat is, they do not necessarily impact a system’s architectureHow one defines “principal” will depend on what the stakeholders define as the system goalsArchitecture in action: WWWThis is the Web

Architecture in action: WWWSo is this29Architecture in action: WWWAnd thisWWW in a (Big) NutshellThe Web is a collection of resources, each of which has a unique name known as a uni as long as m resource locator, or “URL”Each resource denotes, in as long as mally, some in as long as mationURI’s can be used to determine the identity of a machine on the Internet, known as an origin server, where the value of the resource may be ascertainedCommunication is initiated by clients, known as user agents, who make requests of servers. Web browsers are common instances of user agents

HADOOP – complete architectureGapA gap remains between the prescriptive architecture, which concerns decisions, in addition to the descriptive architecture, which concerns programmatic elementsAssignment 2Will be out on Wednesday

Baier, Agnieszka Managing Editor

Baier, Agnieszka is from United States and they belong to Meteoritics & Planetary Science and they are from  Tucson, United States got related to this Particular Journal. and Baier, Agnieszka deal with the subjects like Alternative Energy; Meteorology

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