Systemutveckling Chapter eleven overview

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1 Systemutveckling Chapter eleven overview
SECTION 11.1 – DEVELOPING ENTERPRISE APPLICATIONS Developing Software The Systems Development Life Cycle Software Development Methodologies Developing Successful Software SECTION 11.2 – THE SYSTEMS DEVELOPMENT LIFE CYCLE (SDLC) Systems Development Life Cycle Phase 1: Planning Phase 2: Analysis Phase 3: Design Phase 4: Development Phase 5: Testing Phase 6: Implementation Phase 7: Maintenance Software Problems are Business Problems

2 11.1. DEVLOPING ENTERPRISE APPLICATIONS
Software that is built correctly can transform as the organization and its business transforms Software that effectively meets employee needs will help an organization become more productive and enhance decision making Software that does not meet employee needs may have a damaging effect on productivity and can even cause a business to fail Discuss the famous Nike SCM failure Organizations must learn how to build and implement disruptive technologies, such as software for wireless devices, to remain competitive Software that is built correctly can support agile organizations and can transform as the organization and its business transforms Software that effectively meets employee needs will help an organization become more productive and enhance decision making Software that does not meet employee needs may have a damaging effect on productivity and can even cause a business to fail

3 Vad är en IS-utvecklare?
Ingenjör, konstruktör, tekniker? eller Designer, kreatör, konstnär Citat Programmining is fun Developing quality software on a business basis is hard

4 Kvalitet i system PRODUCT REVISION - Maintainability Can I fix it ?
- Flexibility Can I change it ? - Testability Can I test it ? PRODUCT TRANSITION - Portability Will I be able to use it on another machine ? - Reusability Will I be able to reuse some of the software ? - Interoperability Will I be able to interface it with another system ? PRODUCT OPERATIONS - Correctness Does it do what I want ? Vanligast - Reliability Does it do it accurately all of the time ? - Efficiency Will it run on my hardware as well as it can ? - Integrity Is it secure ? - Usability Is it well designed for the user ? + Does it do the right thing ? + Is it economically relevant ?

5 Systemdiagnos ur användarens perspektiv
Verksamhetsstöd. Frågor som rör informationens aktualitet, riktighet och fullständighet och om systemfunktionerna passar verksamheten. Ex ”Är info från systemet så fullständig att den kan användas direkt ?” Funktionalitet. Frågor om hur lätt det är att använda systemet, svarstider etc. Ex ”Erhålls info vid rätt tidpunkt ?” Kunskap och support. Frågor som rör dokumentation och utbildning. Ex ”Tycker Du att systemets bruksanvisning är lätt att förstå?”. Går det att få hjälp ? Systemförvaltningsorganisation. Frågor som rör ansvar och befogenheter i samband med systemets drift. Ex ”Sker uppföljning av onormala händelser i systemet ?”. ”Korrigeras fel inom rimlig tid?” Tillgänglighet. Är systemet alltid tillgängligt då jag har behov av det? Säkerhet och skydd Är data tillräckligt säkrade och skyddade?

6 Utvecklingsprinciper enligt RUP
Kravdriven Arkitektur-fokuserad Risk-fokuserad Komponentinriktad Iterativ Kvalitet i fokus Hantera ändringar

7 CMM - Kvalitet i utvecklingsprocessen
Level 1- INITIAL Processes are ad hoc and sometimes chaotic. Because few processes are defined, successful projects often depend on heroic individual effort. Level 2- REPEATABLE Basic project management processes are used to track cost, schedule, and functionality. The discipline exists to repeat previous success with similar projects. Level 3- DEFINED Both management and technical processes are documented and integrated into a standard software process for the organization. Projects use an approved, tailored version of the standard software processes. Level 4- MANAGED Detailed measures of the software process and product quality are collected and that information is used to understand both the product and the process in quantitative terms. Level 5- OPTIMIZING Continuous process improvement is facilitated by quantitative feedback from the process and by doing pilot studies of innovative ideas and technologies.

8 The systems development life cycle (sdlc)
CLASSROOM EXERCISE Around SDLC Break your students into groups and have them correlate the SDLC to building a house. This activity helps students understand the different types of activities that occur during each phase of the systems development life cycle Have your students present their answers to the entire class

9 The systems development life cycle (sdlc)
Planning phase – project goals - förstudie Analysis phase – Business requirements – Krav/Requirements Design phase – involves describing the desired features and operations of the system including screen layouts, business rules, process diagrams, pseudo code, and other documentation Development phase – involves taking all of the detailed design documents from the design phase and transforming them into the actual system Testing phase Implementation phase – involves placing the system into production so users can begin to perform actual business operations with the system Maintenance phase – involves performing changes, corrections, additions, and upgrades to ensure the system continues to meet the business goals CLASSROOM EXERCISE Space Needle Exercise Break your students into groups and give them equal materials from a Tinker Toy set, a Zome set, or a product of your choice. Give them each the following instructions and observe the groups as they build their prototypes. Review the IM for details on the project

10 RUP (Rational Unified Process)

11 Software development methodologies
There are a number of different software development methodologies including: Waterfall Rapid application development (RAD) Extreme programming Agile Waterfall methodology – a sequential, activity-based process in which each phase in the SDLC is performed sequentially from planning through implementation and maintenance Rapid application development methodology (RAD) – emphasizes extensive user involvement in the rapid and evolutionary construction of working prototypes of a system to accelerate the systems development process Extreme programming (XP) methodology – breaks a project into tiny phases, and developers cannot continue on to the next phase until the first phase is complete Agile methodology – a form of XP, aims for customer satisfaction through early and continuous delivery of useful software components

12 Utvecklingsprinciper, en annan indelning
TOTAL/-HELHETS-ANSATS (Bokens Waterfall method) Helheten specificeras, konstrueras och implementeras ITERATIV PRINCIP Tillverka i olika utgåvor:1.0, 1.1, ………… Skillnaden mellan två utgåvor kan vara att man fördjupat komplexiteten, ex bilder med animation. Skälet till att arbeta iterativt kan vara att utvecklingsteamet är inte moget för en totalansats eller att man vill pröva och lära ny sig teknik INKREMENTELL PRINCIP Ett inkrement är att man lagt till en funktion, ex en statistikfunktion. Skälet är att man vill införa en produkt etappvis av ekonomiska eller av andra skäl

13 Rapid Application Development Methodology (RAD)
Rapid application development methodology (RAD) – emphasizes extensive user involvement in the rapid and evolutionary construction of working prototypes of a system to accelerate the systems development process The prototype is an essential part of the analysis phase when using a RAD methodology Prototype – a smaller-scale representation or working model of the users’ requirements or a proposed design for an information system RAD is a more popular route for system development projects The fundamentals of RAD include: Focus initially on creating a prototype that looks and acts like the desired system Actively involve system users in the analysis, design, and development phases Accelerate collecting the business requirements through an interactive and iterative construction approach

14 XP – Extreme Programming. Lättrörlig utveckling(Agile)
Project board Krav Test fall Komponenter som skall skapas TIMEBOXED DAGLIG Test-process Team Användare Programmerare Par Bygg-process Ger kontinuerligt användbara resultat: Tillfredställelse och trovärdighet

15 Också systemutveckling: Standardsystem – Köpta system

16 Processen för att köpa system
Behovsanalys Förutsättningsanalys Marknadsundersökning Leverantörsbedömning Offertbegäran Jämförelse Urval Demonstration Behovskomplettering Utvärdering Primärval Testkörning Förhandling Beslut Delgivning Källa ’Att välja Standardsystem.’ Anveskog m.fl.

17 Att köpa system – fördelar & nackdelar
Möjliga Fördelar Utprövat - fungerar Snabbare installation Billigare utveckling och underhåll Säkrare kalkyl Erfarenhet inbyggd i systemet Samordnad verksamhet Leverantören utvecklar och anpassar till nya plattformar etc. Möjliga Nackdelar Förhastade beslut Underskattning av anpassningsbehov Överanpassning Täcker endast en del av kravområdet Leverantörsberoende

18 Också systemutveckling: End user development
Exempel Access + SQL Definiera formulär och databastabeller Front Page Konstruktion av webbsidor Excel Skapa ”ekonomisystem” Fler ?

19 Verifiera och validera
Problem Önskemål Beställning Kravspec System Validera (Genomgångar & användning) Verifiera (Tester)

20 11.2. THE SYSTEMS DEVELOPMENT LIFE CYCLE SDLC
Large, complex IT systems take teams of architects, analysts, developers, testers, and users many years to create The systems development life cycle is the foundation for many systems development methodologies such as RAD and agile Systems development life cycle – the overall process for developing information systems from planning and analysis through implementation and maintenance CLASSROOM OPENER Finding a Good Fit Projects fail for a number of varied reasons. Nick Baker, a 37-year-old system architect at Microsoft, knows that well. A British transplant at the software giant's Silicon Valley campus, he went from failed project to failed project in his career. He worked on such dogs as Apple Computer's defunct video card business, 3DO's failed game consoles, a chip startup that screwed up a deal with Nintendo, the never successful WebTV and Microsoft's canceled Ultimate TV satellite TV recorder. But Baker finally has a hot seller with the Xbox 360, Microsoft's video game console launched worldwide last holiday season. The adventure on which he embarked four years ago would ultimately prove that failure is often the best teacher. His new gig would once again provide copious evidence that flexibility and understanding of detailed customer needs will beat a rigid business model every time. And so far the score is Xbox 360 one and the delayed PlayStation 3 nothing.

21 SDLC Walk the students through the systems development life cycle:
Planning phase – involves establishing a high-level plan of the intended project and determining project goals Analysis phase – involves analyzing end-user business requirements and refining project goals into defined functions and operations of the intended system Design phase – involves describing the desired features and operations of the system including screen layouts, business rules, process diagrams, pseudo code, and other documentation Development phase – involves taking all of the detailed design documents from the design phase and transforming them into the actual system Testing phase – involves bringing all the project pieces together into a special testing environment to test for errors, bugs, and interoperability, in order to verify that the system meets all the business requirements defined in the analysis phase Implementation phase – involves placing the system into production so users can begin to perform actual business operations with the system Maintenance phase – involves performing changes, corrections, additions, and upgrades to ensure the system continues to meet the business goals

22 Primary planning activities include
PHASE 1: PLANNING Planning phase – involves establishing a high-level plan of the intended project and determining project goals Primary planning activities include Identify and select the system for development (Se nästa bild) Assess project feasibility Develop the project plan Ask your students if any of them have ever been involved in the planning phase for a systems development effort Ask them to list additional activities they might have performed during the planning phase Ask your students to keep in mind that there are literally hundreds of different additional activities that could be performed during each phase

23 Förändringsanalys Nulägesanalys
Kartlägg verksamheten, dess ärendeflöden och dess processer. Kartlägg funktioner i nuvarande system. Förändringsanalys Lista problem, orsaker och konsekvenser Gör en målmodell och definiera CRF (Critical Success Factors) Analysera möjligheter/ åtgärder och effekter. Helst ekonomiskt kvantifierade Prioritera möjligheter/ åtgärder Välj strategi/ åtgärder och avgränsa systemområdet Beskriv önskat läge Funktioner i nytt system. Översiktligt/ grovt beskrivna. Nya ärendeflöden och verksamhetsprocesser.

24 Identify and Select the System for Development
Discuss each of the evaluation criteria discussed in the Figure Value chain analysis – systems with greater value are given priority over systems with less value Strategic alignment – projects that are in line with the organization's strategic goals and objectives are given priority over projects not in line with the organization's strategic goals and objectives Cost/benefit analysis – determines which projects offer the organization the greatest benefits with the least amount of cost Resource availability – determine the amount and type of resources required to complete the project and determine if the organization has these resources available Project size, duration, and difficulty – determine the number of individuals, amount of time, and technical difficulty of the project

25 Assess Project Feasibility
Feasibility study – determines if the proposed solution is feasible and achievable from a financial, technical, and organizational standpoint Different types of feasibility studies Economic feasibility study Operational feasibility study Technical feasibility study Schedule feasibility study Legal and contractual feasibility study Riskanalys Stora system innebär risk Okänt område innebär risk Economic feasibility study – (cost-benefit analysis) – identifies the financial benefits and costs associated with the systems development project Operational feasibility study – examines the likelihood that the project will attain its desired objectives Technical feasibility study – determines the organization’s ability to build and integrate the proposed system Schedule feasibility study – assesses the likelihood that all potential time frames and completion dates will be met Legal and contractual feasibility study – examines all potential legal and contractual ramifications of the proposed system Which type of feasibility study would be appropriate for each of the following: Implementation of a new payroll system Implementation of a new CRM system Implementation of a new module to an existing CRM system Implementation of a new ERP system Implementation of a additional functionality to an existing KM system

26 Develop the Project Plan
Developing the project plan is a difficult and important activity The project plan is the guiding force behind on-time delivery of a complete and successful system Continuous updating of the project plan must be performed during every subsequent phase during the SDLC

27 Primary analysis activities include: Gather business requirements
PHASE 2: ANALYSIS Analysis phase – involves analyzing end-user business requirements and refining project goals into defined functions and operations of the intended system Primary analysis activities include: Gather business requirements Create process diagrams Perform a buy vs. build analysis Ask your students which analysis activity is the hardest Ans: Gathering business requirements is the typically one of the hardest tasks to perform on any project and is the number one reason why projects fail “Bad Business Requirements” Why is gathering business requirements so difficulty? It takes many different people to perform organizational activities and they all have to be involved in writing the business requirements Writing detailed business requirements is difficult (review closing case two – Reducing Ambiguity in Business Requirements) Business requirements continuously change

28 Gather Business Requirements
Business requirements – the detailed set of business requests that the system must meet in order to be successful Different ways to gather business requirements Joint application development (JAD) session – where employees meet to define or review the business requirements for the system Interviews Questionnaires Observations Review business documents What other methods could you use to gather business requirements? Comparing different organizations’ processes with best of breed processes – for example looking at Dell’s supply chain Comparing across industries, for example reviewing CRM practices in different hotels and restaurants to apply to a utensil manufacturer Reviewing magazines, articles, and literature to determine new processes, technology, and innovation

29 Gather Business Requirements
The system users review the requirements definition document and determine if they will sign-off on the business requirements Requirements definition document – contains the final set of business requirements, prioritized in order of business importance Sign-off – the system users’ actual signatures indicating they approve all of the business requirements Why is obtaining a physical “sign-off” such a big deal? When someone is asked to put their actual signature on something they take it much more seriously than just a verbal OK. For this reason, asking someone to sign-off helps to ensure they are actually reading the document, understanding the document, and most importantly, in agreement with the document. Ask your students how they would treat a situation where they were asked to sign a document that details their exact net worth. Chances are they would be sure to review it inside out and upside down, as the ramifications of an inaccurate net worth can cause a myriad of issues such as bad credit and the inability to obtain a mortgage.

30 Avvägning och balans krävs
Datorns styrka Alltid tillgänglig Kan överblicka stora datamängder Arbetar snabbt Utföra arbete på ett systematiskt och likartat sätt Kommer ihåg Människans styrka Fantasi Göra bedömningar Upptäcka onormala händelser Förståelse Förmåga att bedöma och se helheten Hantera avvikelser Mänskliga behov Använda kunskaper Meningsfullhet Självständighet Sociala kontakter Balans jobb-fritid BALANS Företagets krav Lönsamhet Flexibilitet Utveckling Samarbete med andra Kundrelationer produktutveckling

31 Två typer av design Användarcentrerad Utgå från arbetssituationen
Datorisera för att stödja och underlätta Teknikcentrerad Utgå från arbetsuppgiften och datorns möjligheter Användaren följer systemet och kompletterar datorn Exempel AC : Programmen klarar fler steg i arbetsflödet sammanhängande TC: Användaren får skifta program mellan olika moment i arbetet AC: Användaren kan registrera en del av ett ärende och sedan göra tillfälligt uppehåll TC: Databasens kontroller kräver att alla registreringar måste vara kompletta

32 Olika grader av Datorstyrning
Datorstött arbete. Människan avgör. Ex. En ekonom använder Excel Datorlett arbete. Systemet ger vägledning. Ex. En resebyråtjänsteman bokar en resa via ett system Datorstyrt arbete. Systemet styr och beordrar. Ex. I ett automatiskt lager hämtas varor fram automatiskt och en lampa lyser på det som skall plockas Datoriserat arbete. Systemet har tagit över. Ex. Robotisering Tre grundläggande situationer Helt manuellt arbete Samarbete mellan människa och dator. VANLIGAST OCH SVÅRAST Helt automatiserat arbete

33 Användarvänlighet Exempel på intressanta egenskaper för ett system
Enkelt att lära, intuitivt Lättförståeligt och logiskt uppbyggt Följer samma standard som övriga system i företaget Tilltalande layout Kunna navigera via menyer och kunna använda genvägar Tollerant för felstavningar etc Få avbrott Snabbt Möjligheter att korrigera misstag Möjlighet att få förklaringar och hjälp Möjlighet att göra uppehåll i arbetet

34 Olika grader av användarengagemang i utvecklingsprocessen
Bild ur: Alter, Information Systems

35 Create Process Diagrams
Process modeling – graphically representing the processes that capture, manipulate, store, and distribute information between a system and its environment Common process modeling diagrams include Data flow diagram (DFD) – illustrates the movement of information between external entities and the processes and data stores within the system Computer-aided software engineering (CASE) tools –automate systems analysis, design, and development CLASSROOM EXERCISE Understanding Business Requirements One of the primary reasons why projects fail is due to missing or inaccurate business requirements. This is a great exercise to demonstrate to your students why it is so difficult to gather complete and accurate business requirements. Break your students into groups and provide your students with the instructions below, a piece of blank paper, and two different colored markers. Please create the following picture using the materials provided. Frame 3 inches by 5 inches Use two different colors Use one color for the 3 inches and the other color for the 5 inches Object 1 – Sun Using one color create a solid circle in the top right corner of your frame Create five small lines using the same color coming out from the sun Create five even smaller lines using a different color and place them coming out of the sun Object 2 – Ground The ground should be one color and one inch along the bottom of the picture Place one long line of along the top of the ground Place five circles ½ inch apart along the bottom of the grass Object 3 – Snowman Using one color create three different shaped circles The first circle should be the size of a quarter The second circle should be the size of a nickel The third circle should be the size of a dime Place the first circle in the middle of the picture on top of the ground Place the second circle in the middle of the picture on top of the first circle Place the third circle in the middle of the picture on top of the second circle Using a different color create two small eyes and place them in the middle of the third circle Using the same color as mentioned above, create three small buttons and place two on the second circle and one on the first circle Use four 2 inch pieces to create the snowman’s arms Object 4 – Broom Place 10 small pieces on top of a small circle Create the broom handle by attaching two long pieces to the top of the broom Place the broom in the snowman’s hand Once everyone has completed their pictures, have them take a walk around the class to see what the other groups created. You can be guaranteed that no two pictures will look alike although they were all working off the exact same requirements. This was a simple picture and there was so much ambiguity in the requirements that all of the pictures are different. If this were representative of a real system, then the requirements would have to be so perfect and detailed that all of the pictures would have turned out identical. The biggest issues with business requirements are ambiguity and interpretation.

36 Create Data Flow Diagrams
Användare Funktion i systemet Dataflöde/transaktion Datalagring/DataBas Discuss the sample data flow diagram with your students Explain that the entities send data or requests to processes The processes interact with the data stores Explain to your students that process diagrams are typically performed by a combination of both IT and business personnel IT personnel understand the technology, and business personnel understand the business process, and they are both required to work together to accurately model a system Bild ur: Alter, Information Systems

37 DFD kan förstoras Context-nivå
Ur INFORMATION SYSTEMS, PrenHall - Alter

38 DFD - Förstoring Ur INFORMATION SYSTEMS, PrenHall - Alter

39 Funktioner i systemet - Användningsfall (Use-case)
5 val av läsk + ångerknapp. Automaten returnerar växel. Use Case Actor Systemet System events Stoppa i pengar Ångra Val av läsk System operations Mata ut läsk Returnera pengar Köpa läsk Kund Fylla på läsk Tömma pengar Leverantör Butiksägare Av/på Service Kontrakt En Actor kan förutom människa vara ett annat system eller en maskin

40 Funktioner i systemet - Användningsfall (Use-case), forts.
System events Reg kund Reg varor Tryck klar Actor Systemet Beställa vara Order behandlare Fakturera Reg lagerplock Lager personal Uppdatera databas System adm Kopiera databas

41 Beskrivning av IS-funktioner – Use-Case/ Anv.fall
Namn: Sale Description: Perform a customer sale event Actor: Cashier Stakeholders & Interests: Kund, personal, ekonomiavdelningen ….. Success scenario: Start sale enter items, end sale, recieve payment Alernate scenarios: Pay cache/card, item is missing,……… Two cuolumn events Actor System 1. enter Item-nr display item name, quantity in stock 2. enter quantity confirm ……….. …….. Precondition: Cashier logged in Postcondition: Sale registred, receipt printed Events: Start sale enter items, end sale, recieve payment Logic: If the customer……… If the article…….. If the credit card ……... User Interface Data som används Sale

42 Funktioner i systemet - Annan graf
Client - functions F2 Huvud meny F4 F3 Server - functions

43 Samband IS-funktioner & Verksamhets-processer
Systembeskrivning Verksamhetsbeskrivning F1 Order process F1 Order reg F2 Lager process Kund F2 Lager trans F3 Fakturering Fakt process F3 Leverans process

44 Icke-funktionella krav
PRODUCT REVISION - Maintainability Can I fix it ? - Flexibility Can I change it ? - Testability Can I test it ? PRODUCT TRANSITION - Portability Will I be able to use it on another machine ? - Reusability Will I be able to reuse some of the software ? - Interoperability Will I be able to interface it with another system ? PRODUCT OPERATIONS - Correctness Does it do what I want ? - Reliability Does it do it accurately all of the time ? - Efficiency Will it run on my hardware as well as it can ? - Integrity Is it secure ? - Usability Is it well designed for the user ? + Does it do the right thing ? + Is it economically relevant ?

45 Perform a Buy vs. Build Analysis
An organization faces two primary choices when deciding to develop an information system Buy the information system from a vendor Commercial off-the shelf (COTS) – software package or solution that is purchased to support one or more business functions and information systems SCM, CRM, and ERP solutions are typically COTS Build the information system itself Performing a buy vs. build analysis is a difficult task CLASSROOM EXERCISE COTS Analysis Break your students into groups and assign each group one of the following: Buy a COTS CRM system from Siebel Build a COTS CRM system similar to Siebel Have each team find support for the decision they have been given using the Internet, textbooks, magazines, etc. Once the students have finished building a case that can support their decision, break the room into two sections – one side representing the “buy decision” and one side representing the “build decision” Let the students debate each other and determine if the ultimate decision is a buy or a build

46 Primary design activities include: Design the IT infrastructure
PHASE 3: DESIGN Design phase – involves describing the desired features and operations of the system including screen layouts, business rules, process diagrams, pseudo code, and other documentation Primary design activities include: Design the IT infrastructure Design Functions in detail For review, the IT infrastructure includes the hardware, software, and telecommunications equipment that, when combined, provide the underlying foundation to support the organization's goals Organizations need a solid IT infrastructure to support their IT systems IT infrastructure must meet the organization’s needs in terms of time, cost, technical feasibility, and flexibility

47 Design the IT Infrastructure
Sample IT infrastructure Discuss the sample IT infrastructure with your students Point out the Internet cloud The firewall The routers, servers, workstations, and printers

48 Design System Models Modeling – the activity of drawing a graphical representation of a design Different modeling types include: Graphical user interface (GUI) System Functions (DFD and Program logics) Data model Transactions Graphical user interface (GUI) – the interface to an information system GUI screen design – the ability to model the information system screens using icons, buttons, menus, and submenus Data models – a formal way to express data relationships to a database management system (DBMS) Entity relationship diagram (ERD) – a technique for documenting the relationships between entities in a database If you had to equate building a system to building a house what would occur during the design phase that is similar to modeling? Designing the house in a blueprint

49 Design Data Models Sample entity relationship diagram (ERD)
Discuss the sample ERD with your students Point out the entities and attributes Discuss the relationships

50 Design - Arkitektur Logiskt Dela in SW i delsystem Dela in SW i lager
Fördela SW på HW, ex client-server Syfte Flexibla system med utbytbara delar Kunna fördela arbetet på olika grupper Kunna testa systemet systematiskt

51 Design - Teknik SW Operativsystem Kommunikationssystem
Databashanteringssystem Utvecklingsmiljö/ programmeringsspråk. Ex .NET och JAVA HW Datorer Kommunikationsutrustning etc. Principer, standards och produkter

52 Design - Realtid Händelser Kontroll/ styrning
Analys av systemets olika tillstånd och status Synkronisering Parallella processer Prioriteringsmekanismer Säkerställande av att dead-lines hålls etc. Principer, standards och produkter

53 Design - User interface
Web-gränssnitt Multimedia Hjälpfunktioner etc. Principer, standards och produkter

54 Beskrivning av logik i IS-funktioner - Text
ORDERREGISTRERING Tryck NYORDER. Kundnummer slås in, systemet visar kunddata. Saknas kunden skall kunddata kunna registreras Ett antal artikelnummer och kvantiteter registreras Systemet visar artikeldata Systemet verifierar att önskad kvantitet finns Efter KLAR summeras ordern och visas i sin helhet på skärmen OK resulterar i att ordern skickas till leveransfunktionen. Vidare subtraheras relevanta lagerkvantiteter

55 Beskrivning av IS-funktioner – Mer strukturerad text
INPUT Kund- och resedata BEARBETNING Boka biljett i databasen ……….. OUTPUT Skriv ut biljett på skrivara USER INTERFACE Frame - 7 VOLYMER transaktioner per dag 15 Mb data i databasen PRESTANDAKRAV Max väntetid: 3 sekunder TILLGÄNGLIGHET 24 timmar per dygn

56 IS-funktioner - logik - struktured language
BEGIN IF lagersaldo < miniminivå THEN skapa inköpsorder ELSE do nothing END

57 IS-funktioner - logik - beslutstabeller

58 IS-funktioner - logik - logikflöde, medelvärde
Start Sum = 0 Antal = 0 Medel = Sum / Antal LÄS Värde Utskrift ? Slut ? Ja Ja PRINT Medel Sum = Sum + Värde Antal = Antal + 1 Slut

59 IS-funktioner - logik - control/ interaction
Modul 1 Starta Modul 2 Modul 3 Beräkna (Parametrar 1, 2, 3)

60 IS-funktioner - logik - tillstånd
Externt kommando: Starta System Inaktivt Uppstart Händelse Tillstånd Övergång Internt: Avslut klar Internt: Uppstart klar Avslutning System Aktivt Externt kommando: Avsluta

61 IS-funktioner - logik - synkronisering
Process 1 Process 2 Process 3 Parallella processer Synkronisering Process 4

62 IS-funktioner - algoritmer
Årlig vinst = Årliga intäkter – Årliga kostnader – Investeringskostnad/ Avskrivningstid

63 Primary development activities include: Develop the IT infrastructure
PHASE 4: DEVELOPMENT Development phase – involves taking all of the detailed design documents from the design phase and transforming them into the actual system Primary development activities include: Develop the IT infrastructure Develop the database and programs + Dokumentation m.m Development 1: Develop the IT Infrastructure The platform upon which the system will operate must be built prior to building the actual system In the development phase, the organization purchases and implements the required equipment to support the IT infrastructure Development 2: Develop the database and programs Once the IT infrastructure is built, the organization can begin to create the database and write the programs required for the system IT specialists perform the majority of the tasks associated with the development phase

64 Primary testing activities include: Write the test conditions
PHASE 5: TESTING Testing phase – involves bringing all the project pieces together into a special testing environment to test for errors, bugs, and interoperability, in order to verify that the system meets all the business requirements defined in the analysis phase Primary testing activities include: Write the test conditions Perform the system testing Why is testing so important during the SDLC? Without testing you could release a bad product into the market, which would severely hinder your reputation

65 Write the Test Conditions
Test condition – the detailed steps the system must perform along with the expected results of each step Explain to your students that a typical system can have tens of thousand of test conditions. Ask your students how many test conditions would be required to test Microsoft Word Cut and Paste functionality only Ask your students how many test conditions to test all the different combinations of font, font size, font style, and different lengths Here a few sample test conditions for an example: Cut Times New Roman, Font size 10, Bold, Italic, Two words Cut Times New Roman, Font size 11, Bold, Italic, Two words Cut Times New Roman, Font size 10, Bold, underline, Two words Cut Times New Roman, Font size 11, Bold, underline, Two words Cut Times New Roman, Font size 10, Bold, underline, Complete sentence Cut Times New Roman, Font size 11, Bold, underline, Two pages of text Paste Times New Roman, Font size 10, Bold, Italic, Two words Paste Times New Roman, Font size 11, Bold, Italic, Two words Paste Times New Roman, Font size 10, Bold, underline, Two words Paste Times New Roman, Font size 11, Bold, underline, Two words Paste Times New Roman, Font size 10, Bold, underline, Complete sentence Paste Times New Roman, Font size 11, Bold, underline, Two pages of text Just imagine all of the thousands of test conditions just with different fonts, per size, per type, per length, and this is just for cut and paste Imagine all of the test conditions to test the advanced mathematical formulas in Excel

66 Perform the System Testing
Different types of testing Unit testing – tests each unit of code upon completion Application (or system) testing – verifies that all units of code work together Integration testing – exposes faults in the integration of software components or units Backup and recovery testing – tests the ability of an application to be restarted after failure Documentation testing – verifies instruction guides are helpful and accurate User acceptance testing (UAT) – tests if a system satisfies its acceptance criteria + belastningstester Rank the tests in order of importance for a system release All tests are important and must be performed to ensure a system functions properly and users know how to use it

67 PHASE 6: IMPLEMENTATION
Implementation phase – involves placing the system into production so users can begin to perform actual business operations with the system Primary implementation activities include: Write detailed user documentation Determine implementation method Provide training for the system users Surprisingly, many projects fail during implementation No matter how great the system is, if the users do not want the system or cannot use the system, it will fail

68 Write Detailed User Documentation
System users require user documentation that highlights how to use the system User documentation – highlights how to use the system Ask your students to discuss situations where they have used user documentation to support an issue or question they were encountering with a system How helpful was the documentation? What was wrong with documentation? What could have improved the documentation? Unfortunately, IT system documentation is notoriously difficult to understand and full of errors!! Be sure your users are just as concerned about the documentation that supports the system as they are that the system works. Using the old “Hit by a Bus” metaphor usually helps to ensure the importance of documentation

69 Determine Implementation Method
Four primary implementation methods Parallel implementation Plunge implementation Pilot implementation Phased implementation Parallel implementation – using both the old and the new system until it is evident that the new system performs correctly Plunge implementation – discarding the old system completely and immediately starting to use the new system Pilot implementation – having only a small group of people use the new system until it is evident that the new system performs correctly and then adding the remaining people Phased implementation – implementing the new system in phases, and then implementing the remaining phases of the new system Ask your student which implementation they would want if they were involved with the implementation of a new CRM system Which method contains the least risk? Which method contains the most risk? Which method is easiest for the users? Which method is hardest for the users?

70 Provide Training for the System Users
Organizations must provide training for system users Two most popular types of training include: Online training – runs over the Internet or off a CD-ROM Workshop training – set in a classroom-type environment and led by an instructor Ask your students to discuss situations where they have taken online or workshop training How helpful was the training? What was wrong with training? What could have improved the training?

71 Primary maintenance activities include:
PHASE 7: MAINTENANCE Maintenance phase – involves performing changes, corrections, additions, and upgrades to ensure the system continues to meet the business goals Primary maintenance activities include: Build a help desk to support the system users Perform system maintenance Provide an environment to support system changes Systems spend the majority of their life in the maintenance phase

72 Build a Help Desk to Support the System Users
Internal system users have a phone number for the help desk they call whenever they have issues or questions about the system Help desk – a group of people who respond to internal system user questions Providing a help desk is an excellent way to provide comprehensive support for new system users Have you ever used a help desk? Why? Was the help desk useful? Did you get your problem resolved? What could the company have done differently to help you resolve your problem more effectively?

73 Perform System Maintenance
Maintenance – fixing or enhancing an information system Different types of maintenance include: Adaptive maintenance Corrective maintenance Perfective maintenance Preventative maintenance Adaptive maintenance – increases system functionality Corrective maintenance – repairs defective systems Perfective maintenance – enhances systems Preventative maintenance – reduces chances of system failure

74 Support System Changes
An organization must modify its systems to support the business environment It typically accomplishes this through change management systems and change control boards Change management system – a collection of procedures to document a change request and define the steps necessary to consider the change based on the expected impact of the change Change control board (CCB) – responsible for approving or rejecting all change requests Why is change control so important to an organization? Change occurs and an organization must plan for and support system changes Without changes the organization could not change and grow

75 Software problems are business problems
Primary reasons for project failure include Unclear or missing business requirements Skipping SDLC phases Failure to manage project scope Scope creep – occurs when the scope increases Feature creep – occurs when extra features are added Failure to manage project plan Changing technology Provide an example of scope creep We added a new type of discount to our marketing plan Provide an example of feature creep We would like a new logo placed on the top corner of every screen and it should play a song when clicked

76 Software problems are business problems
Find errors early: the later in the SDLC an error is found - the more expensive it is to fix Explain to your students that the cost of finding errors grows exponentially the later the error is found in the systems development life cycle An error found during the analysis and design phase is relatively inexpensive to fix All that is typically required is a change to a Word document However, exactly the same error found during the testing or implementation phase is going to cost the organization an enormous amount to fix because it has to change the actual system Find errors early: the later in the SDLC an error is found - the more expensive it is to fix