Pembangunan Sistem InformasiDR

PEMBANGUNAN SISTEM INFORMASI VS SOFTWARE

REKAYASA SISTEM INFORMASI DAN REKAYASA PERANGKAT LUNAK (James Martin)

Rekayasa Perangkat Lunak

Rekayasa Sistem Informasi

Perancangan

PSI

Analisa

Implementasi

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Karakteristik HardwareTimeFailure rateInfant mortalityWear out

Karakteristik SoftwareTimeFailure rateIdealized Curve

REKAYASA PERANGKAT LUNAKMengapa Rekayasa Perangkat Lunak (Software Engineering) diperlukan ?Karena adanya Permasalahan didalam Perangkat Lunak dan Pengembangannya :Krisis perangkat lunak.Biaya perbaikan kesalahan yang meningkat sejalan dengan tahapan pengembangan.Biaya pemeliharaan perangkat lunak yang besar.Keterlambatan dan kekurangan biaya.

Mengapa Rekayasa Perangkat Lunak Diperlukan ?

Keterlambatan penyampaian produkTidak sesuai dengan spesifikasi , bahkan salahMenafikan aspek non teknisSoftware berukuran besar, dikembangkan oleh team dari berbagai disiplin, secara terus menerus produk dapat mengalami perubahan sepanjang pengembangan dan setelah instalasi

REKAYASA PERANGKAT LUNAK Mengapa Rekayasa Perangkat Lunak diperlukan ? Krisis Perangkat LunakBiaya perangkat lunak cenderung meningkat dan melebihi biaya perangkat kerasSOFTWARE COSTHARDWARE COSTSource : Electronic design, Jan 1981

REKAYASA PERANGKAT LUNAK Mengapa Rekayasa Perangkat Lunak diperlukan ?Biaya perbaikan kesalahan yang meningkat sejalan dengan tahapan pengembanagan. (Sumber : Boehm, software Engineering Economics 1981)Perbaikan kesalahan pada tahap analisa memerlukan biaya 2 satuan. Perbaikan untuk kesalahan yang sama pada tahap operasi memelukan biaya 200 satuan1000500200100502010521RequirementAnalysisDesignCodeDevelopmentTestAcceptanceTestOperationLarge software projectsIBM-SSDGTE80%Median (TRW survey) 20%SAFEGUARD8SMALLER SOFTWARE PROJECTS(Boehm, 1980)

REKAYASA PERANGKAT LUNAKMengapa Rekayasa Perangkat Lunak Diperlukan ?Survei tentang kelambatan dan kekurangan biaya serta beberapa penyebabnya. ( Blum, GAO Report FGMSD 80-4 Revisited, ACM Sigsoft Software Engineering Notes, No. 1 Jan 1987 )VeryCommonFairlyCommonNot VeryCommonVeryRateNeverOccursDonttKnowSoftware development has dollaroverrun21.229.225.79.76.23.0Software development has calendaroverrun30.131.925.78.01.82.7The delivered software must becorrected or modified by in-houseprogrammer before it is usable8.834.535.413.36.21.8The software is paid for but never used-3.616.157.120.52.7The delivered software is difficult tomodify5.337.238.111.54.43.5The contractors programming practicesare such that sofware is easilyunderstood by agency program14.262.815.06.2-1.8CAUSECase Number123456789Agency estimated its own state of progress when it let the contractXXXXIncorrect agency management action, such as using inapporapriatecontractXXXXAgency failed to specify requirement adequtelyXXXXXXXAgency overcommited it seltXXagency failed to manage during execution, including executivechangesXXXXXAgency failed to adequately inspect and testXXXXX

REKAYASA PERANGKAT LUNAK Mengapa Rekayasa Perangkat Lunak diperlukan ? Biaya pemeliharaan perangkat lunak yang besar. Corrective (21%), adaptive (25%), preventive (4%) dan perfective (50%)

49438(Sumber : Boehm, Software Engineering Economic 1982)Biaya pemeliharaan lebih besar dari biaya pengembangan perangkat lunak.PemeliharaanPengembanganLain-lain49%43%8%

Aktivitas perawatan software

KUALITAS SOFTWARE: IS0 9126

KarakteristikSub karakteristikFunctionality: software untuk menjalankan fungsinya sebagaimana kebutuhan sistemnyaSuitability, Accuracy, Interoperability,SecurityReliability:Kemampuan software untuk dapat tetap tampil sesuai dengan fungsinya ketika digunakanMaturity, Fault tolerance, RecoverabilityUsability:Kemampuan software untuk mudah dimengerti, dipelajari, digunakan dan disukai penggunaUnderstandability, Learnability, Operability, AttractivenessEfficiency: Kemampuan software untuk menampilkan performans relatif terhadap penggunaan sumberdayaTime Behavior, Resource UtilizationMaintainability: Kemampuan software untuk dimodifikasi (koreksi,adaptasi,perbaikan)Analyzability, Changeability, Stability, TestabilityPortability: Kemampuan software untuk ditransfer dari satu lingkungan ke lingkungan lainAdaptability, Installability

K

REKAYASA PERANGKAT LUNAKUsaha untuk mengatasi permasalahan dalam perangkat lunak dilakukan melalui Rekayasa Perangkat Lunak atau Software Engineering.Rekayasa Perangkat lunak didefinisikan sebagai penerapan pengetahuan keilmuan secara praktis dalam perancangan dan pengembangan program dan dokumentasi terkait yang diperlukan untuk mengsembangkan, mengoperasikan dan memelihara program-program tersebut.(Boehm Software Engineering IEEE Trans on Computer).

REKAYASA PERANGKAT LUNAK AKTIVITAS REKAYASA PERANGKAT LUNAKPengembangan perangkat lunak (software development).Manajemen proyek (project management).Metrik perangkat lunak (software metric).Pemeliharaan perangkat lunak (software maintenance).Jaminan kualitas perangkat lunak (software quality assurance).Manajemen konfigurasi perangkat lunak (software configuration management). PENGEMBANGAN PERANGKAT LUNAKProses perangkat lunak (software process) Metodologi perangkat lunak (software methodology).

MODELCode and FixSystem Development Life Cycle (SDLC)PrototypingSpiralCASE (Computer Aided Software Engineering)

CODE AND FIX MODEL.TAHAP-TAHAPNYA :CODE (PEMROGRAMAN).FIX (PERBAIKAN/PEMELIHARAAN).KRITERIA TRANSISI :CODE (PROGRAM).CATATAN :Proses pengembangan perangkat lunak pada awal era pengolahan data.Menggunakan 3GL atau lebih rendah.Biaya pemeliharaan yang besar.

PROSES PERANGKAT LUNAK SDLC (System Development Life Cycle)TAHAP-TAHAPNYA :InvestigasiAnalisa.Perancangan.Pengkodean.Pengoperasian.Pemeliharaan.KRITERIA TRANSISI :Dokumentasi.CATATAN :Sering dikenal sebagai Document Driven Software ProcessMerupakan perbaikan dari code and fix, dan sampai saat ini merupakan salah satu proses perangkat lunak yang paling banyak digunakan.

Bernhard Boar has defined prototyping as A specific strategy for performing requirements definitions wherein user needs are extracted, presented, and successively refined by building a working model ofthe ultimate system quickly and in its working context.

Connell and Shafer: A software prototype is a dynamic visual model providing a communication tool for customer and developer that is far more effective than either narrativeprose or static visual models for portraying functionality.

It has been described as: functional after a minimal amount of effort a means for providing users of a proposed application with a physical representation of key parts of the system before system implementation flexible modifications require minimal effort not necessarily representative of a complete system.

PROTOTYPINGTAHAPAN: Identifikasi kebutuhan awal, prototyping, penggunaan dan evaluasi prototipe (feedback),Revisi Prototyping ( Iterasi 1n), Penerimaan/Persetujuan End User, Implementasi Sistem, Operasionalisasi dan Pemeliharaan KRITERIA TRANSISI :CODE (PROGRAM)CATATAN :Sering dikenal sebagai Code Driven Software ProcessMerupakan salah satu proses perangkat lunak yang mulai banyak digunakan saat ini.Banyak memanfaatkan 4GL dan Application Generator.Dibandingkan dengan SDLC :Produktivitas lebih baikKelengkapan fungsi dari sistem kurang baikKeterpaduan (integrasi) sistem kurang baikAlternatif STRUCTURED RAPID PROTOTYPING.

PROSES PERANGKAT LUNAKIDENTIFIKASI KEBUTUHANAWAL PEMAKAIMENGGUNAKAN DANMENGEVALUASIPROTOTYPEREVISI PROTOTYPEMEMBUAT SEBUAHPROTOTYPECONTOH MODEL(PROTOTYPE)SISTEM YANGDISERAHKANPROTOTYPING Tahap-tahap :TidakSetujuImplementasi

PENGEMBANGAN PROTOTIPE SEBAGAI SUATU PROSES PENGEMBANGAN APLIKASI SECARA CEPAT (contoh produk NETSCAPE)

8Design Derivation6Prototyping Iteration1Projek Plan2Rapid Analysis7UserApproval5Functions3DatabaseCreation9Tuning4Menus10Operation & MaintenancePROSES PERANGKAT LUNAK PROTOTYPING - STRUCTURED RAPID PROTOTYPING(Sumber : J.L. Connel, L.B. Shafer, Structured Rapid Prototyping, Prentice Hall, 1989)

CONTOH PENGEMBANGAN SISTEM DENGAN MENGGUNAKANPENDEKATAN PENGEMBANGAN PROTOTYPE

Team. A few end users and IS developers form a team to develop a business applicationSchematic. The initial prototype schematic design is developed.Prototype. The schematic is converted into a simple point-and-click prototype using prototyping tools.Presentation. A few screens and routine linkages are presented to users.Feedback. After the team gets feedback from users, the prototype is retaired.Reiteration. Further presentations and reiteration are made.Consultation. consultation are held with central IT developers/consultants to identify potential improvements and conformance to existing standards of the organization.Completion. The prototype is converted into a finished application.Acceptance. Users review and sign off on their acceptance of the new systemInstallation. The new application software is installed on network servers

PROSES PERANGKAT LUNAK MODEL SPIRALKRITERIA TRANSISI :Dokumen hasil analisa resiko.CATATAN :Sering dikenal sebagai : Risk Driven Software ProcessUntuk pengembangan proyek yang berskala besar, dengan memperhatikan pengaruh resiko dilihat dari segi finansial maupun keamanan (jiwa manusia).Kombinasi SDLC, Prototyping dan Risk Analysis.

MODEL SPIRAL tahap-tahapnya :DetermineObjectivesAlternativesConstraintsSpiral Model

PlanningToolsetCOMPUTER AIDED SOFTWARE ENGINEERING (CASE)AnalysisToolsetDesignToolsetInformationIntegratorCodeGenerationToolsetDatabaseGenerationToolsetSystemInterfaceWork StationRepositoriesThe planning Toolset begins the development processwith information strategyplanning from a high-levelbusiness vantage pointThe Analysis Toolsetfocuses on correctlycapturing detailed businessrequirements early indevelopment processThe Design Toolsetprovides detailedspecifications of the systemsolutionThe Information Integratorintegrates systemspscifications, check themfor consistency andcompleteness, and recordsthem in the repositoriesWorkstation repositoriesand a server repositorydocument informationabout systems beingdeveloped or in useThe Code GenerationToolsetproducesprogramcode basedon systemspecificationThe DatabaseGenerationToolsetgeneratesinformationneeded fordata storageand accessThe SystemInterfaceprovides forfile transfersand queryresportingCase WorkstationCaseServer Repository

END USER DEVELOPMENT

Define a problem or opportunity using systems thinking

Develop and evaluate alternative system solutions

Select the system solution that best meets your requirements

Design the selected system solution to meet your requirements

Implement and evaluate the success of the designed systemPEMBANGUNAN SISTEM INFORMASI : PENDEKATAN SISTEM

SIKLUSPENGEMBANGANSISTEM INFORMASI(SDLC)

Memahami Permasalahan danPeluangSistemSIKLUSPENGEMBANGANSISTEM INFORMASI

Pengembangan SolusiSistem Informasi

Implementasi SolusiSistem Informasi(SDLC)

INVESTIGASI SISTEM PRODUK: TUJUAN, RUANG LINGKUP DAN PERUMUSAN MASALAHTOOLS: MATRIK KOMPONEN SISTEM INFORMASI DLLNYA.Interviews with employees, costumers, and managers.Questionnaires to appropriate end users in the organization.Personal observation, videotaping, or involvement in end user work activities.Examination of documents, reports, procedures manuals, and other documentation.Development, simulation, and observation of model of the work activities.

PRODUK INVESTIGASI SISTEM: LAPORAN STUDI KELAYAKANHow well proposed system supports the strategic objectives of the organizationCost savingsIncreased revenueDecreased investmentIncreased profitsEnd user acceptanceManagement supportCustomer, supplier, and government requirementsHardware, Software, and network capability, reliability and availabilityOrganizational FeasibilityEconomic FeasibilityTechnical FeasibilityOperational Feasibility

TAHAPAN ANALISISPRODUK: FUNCTIONAL REQUIREMENTSUser interface requirements. The input/output needs of end users that must be supported by the information system, including sources, formats, content, volume, and frequency of each type of input and output.Processing requirements. Activities required to convert input into output. Includes calculations, decision rules, and other processing operations, and capacity, throughput, turnaround time, and response time needed for processing activities.Storage requirements. Organization, content, and size of databases, types and frequency of updating and inquiries, and the length and rationale for record retention.Control requirements. Accuracy, validity safety, security, and adaptability requirements for system inputs, processing, output and storage functions.

CONTOH SALAH SATU PENDEKATAN ANALISIS DAN DISAIN YANG MELIBATKAN TIM DAN PENGGUNAAN VIDEOOpen-endedinterviewsOn-site, in-contextobservationsDesign solutions embodied in sketches, mock-ups, simulationsUnderstanding User NeedsCodevelopmentForm SystemsDevelopment TeamFinalSystemDesignDataAnalysisOpen-endedinterviewsCoview video withdevelopersIdentify keyissuesVerify findingswith usersDesign workshops with usersCoview user`s reactionsto design conceptsUser videotapelibrary and databasevideotranscriptssite mapsmock-ups

PRODUK: SYSTEM SPESIFICATIONSUser interface specifications: The content, format, and sequence of user interface products and methods such as display screens, interactive dialogues, audio responses, forms, documents, and reports.Database specifications: Content, structure, distribution, and access, response, maintenance, and retention of databases.Software specifications: The required software package or programming specifications of the proposed system, including performance and control specifications.Hardware and facilities specifications: The physical and performance characteristics of the equipment and facilities required by the proposed system.Personal specifications: Job descriptions of persons who will operate the system.

Tahapan Disain

User InterfaceDesign

DataDesign

ProcessDesign

Screen, Form, Report, and Dialog designData Element structur DesignProgam and Procedure design

TAHAPAN IMPLEMENTASI

Sample Implementation Process12-*

Evaluate and acquire new hardware and software. Hardware includes computer systems, POS terminals, and telecommunications processors and network facilities. Software includes network management programs and POS transaction processing packages.Develop computer programs or make any necessary modifications to software packages that are acquired.Prepare training materials and documentation on how to operate the new POS system for managers and salespeople.Educate and train managers, salespeople, and information systems personnel to operate the new system.Test the system and make corrections until it operates properlyConvert to the new system on a phased store-by-store basis to minimize disruption. Use the first store converted as a pilot installation to help with testing and training.Perform a postimplementation audit within 30 days of each store's conversion to determine if the new POS systems are achieving their expected advantages.TAHAPAN IMPLEMENTASI

Other Implementation ActivitiesTestingData conversionDocumentationTraining12-*

KONVERSI SISTEMDIRECT CUT OVER ( IMMEDIATE CUT OVER)PHASED IN CUT OVERPARALELL CUT OVERPILOT PROJECT

Major System Conversion Strategies12-*(Plunge)

Post-Implementation ActivitiesSystem MaintenanceCorrective: fix bugs and logical errorsAdaptive: add new functionalityPerfective: improve performancePreventive: reduce chances of failurePost Implementation ReviewCorrect Errors Periodic review/auditSingle most costly activity

12-*

Ujian sd 10 Januari 2015

Jelaskan bagaimana pengembangan sistem informasi dengan menggunakan pendekatan insourcing atau outsourcing di perusahaan !Mantainaibility merupakan salah satu karakteristik dari berkualitas tidaknya suatu software. Jelaskan urgensi mantainaibility ini dalam konteks implementasi suatu sistem informasi di organisasi?Jelaskan bagaimana konversi sistem informasi dapat dilakukan ?

5515567101414217131231918*The keys to successful implementation of a new business systemTestingData conversionDocumentationTraining

System testing may involveTesting and debugging softwareTesting website performanceTesting new hardwareReview of prototypes

Data conversion includesConverting data elements from the old database to the new databaseCorrecting data errorsFiltering out unwanted dataConsolidating data from several databasesOrganizing data into new data subsetsImproperly organized and formatted data is a major cause of implementation failures

User DocumentationSample data entry screens, forms, reportsSystem operating instructionsSystems DocumentationMethod of communication among those developing, implementing, and maintaining a computer-based systemDetailed record of the system designExtremely important when diagnosing problems and making system changes

End users must be trained to operate a new business system or its implementation will failMay involve only activities, such as data entry, or all aspects of system useManagers and end users must understand how the new technology impacts business operationsSystem training should be supplemented with training related toHardware devicesSoftware packages

*Parallel ConversionOld and new systems are run simultaneously until everyone is satisfied thatThe new system functions correctlyThe old system is no longer neededConversion to new system can be single cutover or phased cutoverHas the lowest risk, but the highest costCan cost 4 times more than using the old systemBest choice where an automated system is replacing a manual one

Pilot ConversionScenarios best suited to a pilot conversionMultiple business locationsGeographically diverse locationsAdvantages of single location conversionCan select a location that best represents the conditions across the organizationLess risky in terms of loss of time or delays in processingCan be evaluated and changed before further installations

Phased ConversionA phased or gradual conversionTakes advantage of both the direct and parallel approachesMinimizes the risks involvedAllows the new system to be brought online as logically ordered functional componentsDisadvantagesTakes the most timeCreated the most disruption to the organization over time

Direct or Plunge conversionThe simplest conversion strategyThe most disruptive to the organizationSometimes referred to as the slam dunk or cold-turkey strategyMay be the only viable solution in cases of emergency implementation or if the old and new system cannot coexistHas the highest risk of failureInvolves turning off the old system and turning on the new one

*The single most costly activity

Correcting errors or faults in the systemImproving system performanceAdapting the system to changes in the operating or business environmentRequires more programmers than does application developmentMay exist for years

System Maintenance Four basic categoriesCorrective: fix bugs and logical errorsAdaptive: add new functionalityPerfective: improve performancePreventive: reduce chances of failure

Post Implementation Review Ensures that the newly implemented system meets the established business objectivesErrors must be corrected by the maintenance processPeriodic review/audit of the system as well as continuous monitoring

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