Presentation on theme: "Information Systems Development"— Presentation transcript:
1 Information Systems Development Chapter 10Information Systems Development
2 Study Questions Q1: What is systems development? Q2: Why is systems development difficult and risky?Q3: What are the five phases of the SDLC?Q4: How is system definition accomplished?Q5: What is the users’ role in the requirements phase?Q6: How are the five components designed?Q7: How is an information system implemented?Q8: What are the tasks for system maintenance?Q9: What are some of the problems with the SDLC?How does the knowledge in this chapter help Fox Lake and you?
3 Q1: What Is Systems Development? VideoProcess of creating and maintaining information systemsInvolves all five IS componentsSee author video
4 Q2: Why Is Systems Development Difficult and Risky? Many projects never finished. Those that finish often 200–300% over budget.Some projects finish within budget and schedule, but never satisfactorily accomplish their goals.
5 Five Major Challenges to Systems Development Diseconomies of scale: communication problems, heavy load of benefits, difficult to coordinate, bureaucracy, etc.
6 Q2: Why Is Systems Development Difficult and Risky? (cont’d) Difficult to determine requirementsWhat specifically is system to do?How does wedding planner use new system to reserve a room or building?What does data entry screen look like?How does planner add/reduce facilities once wedding scheduled?What should system do when a wedding is cancelled?Facility schedule system interface with accounting systems? How?Does system need to reserve floor or refrigerator space in restaurant kitchen?Must create environment where difficult questions are asked and answered.
7 Q2: Why Is Systems Development Difficult and Risky? (cont’d) Changing requirementsLarge, long projects aim at moving targetScheduling and budgeting difficultiesHow long to build it?How long to create data model?How long to build database applications?How long to do testing?How long to develop and document procedures?How long for training?How many labor hours? Labor cost?What’s the rate of return on investment?
8 Q2: Why Is Systems Development Difficult and Risky? (cont’d) Changing TechnologyDo you want to stop your development to switch to the new technology?Would it be better to finish developing according to the existing plan?Why build an out-of-date system?Can you afford to keep changing the project?
9 Q2: Why Is Systems Development Difficult and Risky? (cont’d) Diseconomies of scaleBrooks’ Law“Adding more people to a late project makes the project later.”New staff must be trained by productive members who lose productivity while training new members.A later project costs more and increases the unit price.
10 Yes and No Is It Really So Bleak? Systems development is challenging, but solid methodologies exist that are successful when supported and managed properly.Yes and NoSystems development life cycle (SDLC), most common process for systems development.
11 Q3: What Are the Five Phases of the SDLC? Based on problem analysis and decision solving processes
12 Q4: How Is System Definition Accomplished? Team of users and IT professionalsSmall business may hire consultant to work with managers and key employeesFox Lake: Jeff, Laura, Mike, Anne, and other key employees will define system
14 Q4: How Is System Definition Accomplished? (cont’d) Purpose: Increase revenue from wedding eventsGoals: Eliminate or at least reveal schedule conflicts and improve maintenance trackingScope: Specify users or business processes that will be involved, or facilities, functions, events that will be involvedDefine scope for new Fox Lake system
15 Assess Feasibility: Dimensions of Feasibility Cost feasibility (economic feasibility)Approximated, “back-of-the-envelope” analysisPurpose: eliminate infeasible ideas earlyConsider cost of previous projects, operational and labor costsSchedule feasibility and operational feasibilityBall park estimateTechnical feasibilityDo we have the hardware, software, personnel, expertise to complete project?Organizational feasibility (legal feasibility)Fits customs, culture, charter, legal requirements of organizationAlternatively, TELOS – five areas of feasibility - technology feasibility, economic feasibility, legal feasibility, operational feasibility, and schedule feasibility.
16 Form a Project Team Typical team Team composition changes over time Systems analyst and/or business analystManagersProgrammersSoftware testersUsersTeam composition changes over timeActive user involvement is critical throughoutSystem analyst – research problems, plan solutions, recommends hardware and software, coordinates system development to meet business requirementsBusiness analyst – research problems in business processes, work flow designs, organization structure to generate business requirements
17 Q5: What Is the Users’ Role in the Requirements Phase? Review and approve requirementsLaura only person with knowledge of systems development,she will work with development contractor to help specify Fox Lake’s needsComponent design – design phase of SDLC, system is usually decomposed into modules and subsystems for technical design and development.
18 Q6: How Are the Five Components of IS Designed? Determine hardware specificationsPurchase it, lease it, or lease time from hosting serviceDetermine software specificationsOff-the-shelf, in-house developed, customizedDatabase designConvert data model to a database designProcedure designData model - an abstract model that documents and organizes the business data for communication between team members and is used as a plan for developing applications, specifically how data are stored and accessed.Normal, backup, and failure recovery proceduresDesign Job DescriptionsCreate and define new tasks and responsibilities
19 Procedures to Be Designed Figure 10-7Automatic system recovery is a device or process that detects a computer failure and attempts recovery. The device may make use of a Watchdog timer.
20 Design of Job Descriptions Teams of systems analysts and users determine job descriptions and functionsDuties and responsibilities for new jobs and revised jobs coordinated with human resources policies
21 Q7: How Is an Information System Implemented? BuildingTestingConverting
22 Q7: How Is an Information System Implemented? (cont’d) System testingTest planProduct Quality Assurance (PQA vs. QAP)User testingDevelop test plans and test casesFinal say on whether system is “production ready”Alpha testing (internal acceptance), Beta testing (external user acceptance)PQA: the planned and systematic activities with a standard, monitoring of processes and an associated feedback loop that confers error prevention. It may include ensuring conformance to one or more standards, such as ISO 9000 or a model such as CMMI (Capability Maturity Model Integration (CMMI) is a process improvement training and certification program and service administered and marketed by Carnegie Mellon University and required by many DOD and Government programs for government contracts, especially software development.QAP: quality assurance program for quality control in a form.
23 Design and Implementation for the Five IS Components
24 System Conversion Approaches PilotImplement entire system in limited portion of businessAdvantage: Limits exposure to business if system failsPhasedSystem installed in phases or modulesEach piece is installed and testedParallelComplete new and old systems run simultaneouslyVery safe, but expensive, time consumingPlunge (“Big Bang”)High risk if new system fails, no fall back systemOnly used if new system not vital to company operationCisco’s ERP Implementation approach – rapid iterative prototyping (conference room pilot, 0, 1, 2, 3, and cut over).
25 Q8: What Are the Tasks for System Maintenance? Failure is a difference between what system does and what it is supposed to do.
26 Q9: What Are Some of the Problems with the SDLC? Sequence of non-repeated phasesIt rarely works smoothly, causing development team to go back and forth, raising costs and delaying projectSDLC Waterfall MethodBusiness requirements change“Analysis paralysis”—projects spend so much time on documentation it hampers progressRequirements documentation difficultyTime and cost estimates for large project usually way offPeople who make initial estimates know little about how long it will take or costScheduling and budgeting difficulties
27 SDLC Waterfall Method vs. RAD RAD – Rapid application development, is a software development methodology that uses minimal planning in favor of rapid prototyping.
28 The ERP Implementation Method at Cisco Rapid iterative prototypingA series of phases “Conference room Pilots” (CRPs 0, 1, 2 and 3)System Conversion MethodsParallel (keeping the old system running alongside the new system for the first couple of weeks or months)Direct (within a day or over a weekend or holiday period)Pilot (using the new system in only a small section of the company)Phased (taking offline parts of the old system and replacing them with the corresponding parts of the new system)
29 Active Review Q1: What is systems development? Q2: Why is systems development difficult and risky?Q3: What are the five phases of the SDLC?Q4: How is system definition accomplished?Q5: What is the users’ role in the requirements phase?Q6: How are the five components designed?Q7: How is an information system implemented?Q8: What are the tasks for system maintenance?Q9: What are some of the problems with the SDLC?How does the knowledge in this chapter help Fox Lake and you?
30 Experiencing MIS InClass Exercise 10: GardenTraker Suppose that you and two or three other students have been groundskeepers at Fox Lake, and you have decided to go out on your own and open a business that offers landscaping services. Your goal is to develop a list of clients for whom you provide regular and recurring services, such as mowing, weeding, and pool cleaning, as well as specialty services, such as pruning, garden preparation, tree removal, sprinkler installation and repair, and the like.Need information system for tracking customers, services you have provided, and services you are scheduled to provide in the future. As a new small business, you want a simple and affordable system based on Excel or Access. The name of the system is GardenTraker.
31 Experiencing MIS InClass Exercise 10: GardenTraker (cont’d) 1. Explain how you would use the SDLC to develop GardenTraker. 2. Define the scope of your system. 3. Explain the process you would use to determine the feasibility of GardenTraker. List data you need for such an assessment, and explain how you might obtain or estimate that data.
32 Experiencing MIS InClass Exercise 10: GardenTraker (cont’d) Consider just the tracking of recurring services, and list all of the requirements that you can imagine for that functionality. Be specific and answer at least the following:What data will you need?How will you input that data? Show a mockup of a data entry screen, and describe how it will be used.Using your mockup, describe how you will modify recurring service data.Using your mockup, describe how you will cancel a recurring service.Specify any other requirements you believe are important for tracking recurring services.
33 Experiencing MIS InClass Exercise 10: GardenTraker (cont’d) Present your answers to item 4 to the rest of the class and obtain feedback from your classmates.6. Modify your answer to item 4 based upon feedback you received in item 5.7. Considering just the recurring services functionality, do you think it would be better to use Excel or Access for this project? List the criteria you used to answer that question. Summarize the consequences of making a poor choice between these two products.8. What does this short exercise tell you about information systems development? Answer this question in such a way that you could use your answer to demonstrate your critical-thinking skills in a job interview
Your consent to our cookies if you continue to use this website.