1. SYSTEM DEVELOPMENT

2. What are some reasons to create ormodify an information system? To correct problemTo improve in existing systemexisting systemCompetition can Outside group may lead to changemandate change 3. System Development Systems development is the processof defining, designing, testing, andimplementing a new softwareapplication or program. It couldinclude the internal development ofcustomized systems, the creation ofdatabase systems, or the acquisitionof third party developed software. 4. System DevelopmentLife Cycle (SDLC) Six Phases of the System DevelopmentLife Cycle Preliminary Investigation Assesses feasibility and practicality of system System Analysis Study old system and identify newrequirements Defines system from users view System Design Design new/alternative system Defines system from technical view 5. System Development New hardware and software isacquired, developed, and tested System Implementation System installation and training System Operation & Maintenance Daily operation Periodic evaluation and updating 6. Preliminary Investigation SystemSystem Operation Analysis& MaintenanceSystem SystemImplementation n DesignSystem Development 7. Who is a systems analyst? Responsible for designing and developinginformationsystem Liaison between users and ITprofessionals 8. What is the project team? Formed to work on project frombeginning to end Consists of users, systemsanalyst, and other IT professionals Project leaderone member of theteam whomanages and controls project budgetand schedule 9. What is feasibility?Schedule feasibility Measure ofhow suitableFour feasibility system tests:development Operationalwill be to the feasibility company Economic feasibility (also called cost/benefit feasibility) 10. Approaches to SystemsDevelopment Process-Oriented Approach Focus is on flow, use and transformation of datain an information system Involves creating graphical representations suchas data flow diagrams and charts Data are tracked from sources, throughintermediate steps and to final destinations 11. Approaches to SystemsDevelopment Data-Oriented Approach Depicts ideal organization ofdata, independent of where and how dataare used Data model describes kinds of data andbusiness relationships among the data Business rules depict how organizationcaptures and processes the data 12. AlternativeApproachesPrototypingApproach The prototyping approach is used in therequirement gathering and in the analysis phaseto capture the exact requirement of the proposedsystem. After the requirements are frozen, theremaining phases of the development processneeds to be executed to complete thedevelopment of the software system. An e-commerce website, such as shopping site isan example where you can implement theprototyping approach. You can develop theprototype of the various web pages of theshopping site such as catalogue page, productorder page etc., and present it to the customerfor approval. If the customer approves theprototype of the site, requirements are statesagain and the design of the web site is initiated. 13. The prototype is a working system developed totest the behaviour of new system.The prototypegenerates output from input of data fed to it andthis output is evaluated to know knoe possibleenhancements to the prototype. Its requiredwhile: Building an experimental system quickly andcheaply Unclear user requirements 1.User involvement 2.Fast 1.Poor system quality 2.Lack of standard 14. Need for prototyping Enables us to explore the problemspace with the stakeholders. A vehicle for you to communicate thepossible UI design(s) of your system. A potential foundation from which tocontinue developing the system 15. Advantages: * This type of approach of developing the software isused for non-IT-literate people. They usually are notgood at specifying their requirements, nor can tellproperly about what they expect from the software.* It reduces risk of failure, as potential risks can beidentified early and mitigation steps can be taken.* Iteration between development team and clientprovides a very good and conductive environmentduring project. 16. Disadvantages of PrototypingModel: Prototyping is usually done at the cost of the developer. So it should be done using minimal resources. * It is a slow process.*Too much involvement of client, is not always preferred by the developer.*Too many changes can disturb the rhythm of the development team. 17. Application Software Packages Prewritten, pre-coded applicationsoftware, commercially available for saleor lease Geared to common requirements (significant few; Canned functions) Accountsreceivable; Bond & stock management;Computer-aided design (CAD) ;document imaging; E- mail;Enterprise.Resource planning (ERP);Groupware; Health care;Hotel.Management; Internet telephone;Inventory control; Job costing. 18. Enduser development Building the system by end-users withlittle or no formal technical assistance When? ForPersonal & smallapplications WHY? 1.No misunderstanding 2.Fast 19. End-users develop information systemthemselves, with little help fromtechnical specialists; Using 4thgeneration toolsStrengths: Improved requirements determination Increased user involvement &satisfaction 20. Weaknesses: Relatively inefficient Slow transaction processing May carry high/hidden cost 21. Outsourcing Using an external vendor to developor operate an organizations ISs Mission is non-critical applications 1.Reduce costs 2.Predictability 1.Risky 2.Loss of control 22. Contracting: Computer center operations Telecommunications networks 23. Structured methodology(Waterfall) 24. ADVANTAGESA waterfall model helps findproblems earlier on which cancost a business less than if itwas found later on.Requirements will be set andthese wouldnt be changed. As everything is documented anew team member can easilyunderstand whats to be done.Implementers have to followthe design accurately 25. DISADVANTAGES If requirements may change theWaterfall model may not work. Many believe it is impossible to makeone stage of the projects life cycleperfect. Difficult to estimate time and cost foreach stage of the developmentprocess. Constant testing of the design isneeded. 26. System analysis Systems System is an interrelated set of components, withidentifiable boundary, working together for somepurpose A system has nine characteristics: Components----------------------Subsystems Interrelated components A boundary A purpose An environment Interfaces Input Output Constraints 27. System Analysis Systems analysis is a process ofcollecting factual data, understand theprocesses involved, identifying problemsand recommending feasible suggestionsfor improving the system functioning.This involves studying the businessprocesses, gathering operationaldata, understand the informationflow, finding out bottlenecks and evolvingsolutions for overcoming theweaknesses of the system so astoachieve the organizational goals. 28. OBJECTIVES The major objectives of systemsanalysis are to find answers for each business process: What is beingdone, How is it being done, Who is doing it, When is he doing it, Why is itbeing done and How can it be improved? 29. System Design Based on the user requirements and thedetailed analysis of the existing system, the new system must bedesigned. This is the phase of system designing. It is the most crucialphase in the developments of a system. Thelogical system design arrived at as a result of systems analysis is converted into physicalsystem design. Normally, the design proceeds in two stages:Preliminary or General DesignStructured or Detailed Design 30. Preliminary or General Design: In thepreliminary or general design, thefeatures of the new system arespecified. The costs of implementingthese features and the benefits to bederived are estimated. If the project is still considered to befeasible, we move to the detaileddesign stage. 31. Structured or Detailed Design: In thedetailed design stage, computeroriented work begins in earnest. Atthis stage, the design of the systembecomes more structured. Structuredesign is a blueprint of a computersystem. 32. There are several tools and techniquesused for describing the system design ofthe system. These tools and techniquesare: l Flowchart l Data flow diagram (DFD) l Data dictionary l Structured English l Decision table l Decision tree 33. steps The system design involves: i. Defining precisely the required system output ii. Determining the data requirement for producing the output iii. Determining the medium and format of files and databases iv. Devising processing methods and use of software toproduce output v. Determine the methods of data capture and data input vi. Designing Input forms vii. Designing Codification Schemes viii. Detailed manual procedures ix. Documenting the Design 34. SYSTEM IMPLEMENTATIONIt is the process of carrying out the operational plans developed as a part of information system planning . Implementation includes all the activities required to replace the old system by the new system. . The implementation process involves acquisition of IS resources , testing , documentation , installation and conversion process. 35. STEPS Hiring and training the personnels Program development Site preparation Acquisition and installation ofhardware Software aquisition File conversion Documentation 36. FACTORS FOR SUCESSFULIMPLEMENTATION Involving users in projectimplementation Setting up a cohesive project mgt forimplementation Using project mgt tools like , PERT,CPM etc. Use of formal controltools to monitorproject implementation Overcoming user resistance 37. CausesLower user involvement in project implementation Lack of commitment from top mgt for the project Complexity of project Poor mgt of project implementation process. 38. INFORMATION SYSTEM AUDIT 39. Generally Accepted AuditingStandards (GAAS) 40. External versus Internal Auditing External auditors represent theinterests of third partystakeholders, while internal auditorsserve as an independent appraisalfunction within the organization. Internal auditors often perform taskswhich can reduce external audit feesand help to achieve audit efficiencyand reduce audit fees. 41. Elements of an Audit Systematic procedures are used Evidence is obtained tests of internal controls substantive tests Determination of materiality forweaknesses found Prepare audit report & audit opinion 42. Phases of an IT Audit 43. COMPUTER NETWORKS A computer network, or simplya network, is a collection of computers andother hardware interconnected bycommunication channels that allow sharing ofresources and information. Where at leastone process in one device is able tosend/receive data to/from at least oneprocess residing in a remote device, then thetwo devices are said to be in a network. Anetwork is a group of devices connected toeach other. 44. Intranets and extranets Intranets and extranets are parts or extensions of a computernetwork, usually a LAN. An intranet is a set of networks, using the InternetProtocol and IP-based tools such as web browsers and filetransfer applications, that are under the control of a singleadministrative entity. That administrative entity closes theintranet to all but specific, authorized users. Mostcommonly, an intranet is the internal network of anorganization. A large intranet will typically have at least oneweb server to provide users with organizational information. An extranet is a network that is limited in scope to a singleorganization or entity and also has limited connections to thenetworks of one or more other usually, but notnecessarily, trusted organizations .Technically, an extranetmay also be categorized as a CAN, MAN, WAN, or other typeof network, although an extranet cannot consist of a singleLAN; it must have at least one connection with an externalnetwork. 45. Network Devices Wireles s 46. Router, Switch, Hub, Modem, Routers are small physical devices that joinmultiple networks together. Technically, arouter is a gateway device, meaning that itconnects two or more networks and that therouter operates at the network layer ofthe OSI model.Home networks typically use awireless or wired Internet Protocol(IP) router, IP being the most common OSInetwork layer protocol. An IP router such as aDSL or cable modembroadband router joinsthe homes local area network (LAN) tothe wide-area network (WAN)of the Internet. 47. A network switch is a small hardwaredevice that joins multiple computers togetherwithin one local area network (LAN). Networkswitches appear nearly identical to networkhubs, but a switch generally contains moreintelligence (and a slightly higher price tag)than a hub. Unlike hubs, network switchesare capable of inspecting data packets asthey are received, determining the sourceand destination device of each packet, andforwarding them appropriately . 48. Hub Hub is used to create connections betweenstations in a physical star topology. Hub is acentral n/w device that connects networknodes. It is also referred as concentrators. Itenables central n/w management. It can havemultiple inputs & outputs all active at onetime. It Permits large numbers of computer tobe connected on a single or multiple LANs. Itenables high speed communication. Provideconnection for several different media types.(Coaxial, fiber optic, twisted pair). 49. Modem is a computer device that modulatesand demodulates data signals. It enables thecomputer to transmit the data over the phoneline. The data over the telephone line istransmitted in the analog form and when itreaches at the computer at other end it mustbe presented in the digital form so thatcomputer can understand it. The modemtakes the data and converts it in the readableform for your computer i.e. digitalform. Modem IS used on dialupnetworks convert data between the analogform used on telephone lines and the digitalform used on computers. 50. TOPOLOGIES Incomputernetworking, topology refersto the layout of connected devices. Network topologies are categorizedinto the following basic types: bus ring star tree mesh 51. Bus Topology Bus networks (not to be confused with thesystem bus of a computer) use a commonbackbone to connect all devices. A singlecable, the backbone functions as a sharedcommunication medium that devices attachor tap into with an interface connector. Adevice wanting to communicate with anotherdevice on the network sends a broadcastmessage onto the wire that all other devicessee, but only the intended recipient actuallyaccepts and processes the message. 52. Ring Topology In a ring network, every device hasexactly two neighbors for communicationpurposes. All messages travel through aring in the same direction (either"clockwise" or "counterclockwise"). Afailure in any cable or device breaks theloop and can take down the entirenetwork. THE ring network, topologiesare found in some office buildings orschool campuses. 53. Star Topology Many home networks use the startopology. A star network features acentral connection point called a "hubnode" that may be a networkhub, switch orrouter. Compared to thebus topology, a star network generallyrequires more cable, but a failure in anystar network cable will only take downone computers network access and notthe entire LAN. (If the hubfails, however, the entire network alsofails.) 54. Tree Topology Tree topologies integrate multiple startopologies together onto a bus. In itssimplest form, only hub devices connectdirectly to the tree bus, and each hubfunctions as the root of a tree of devices.This bus/star hybrid approach supportsfuture expandability of the network muchbetter than a bus (limited in the numberof devices due to the broadcast traffic itgenerates) or a star (limited by thenumber of hub connection points) alone. 55. Mesh topologies Mesh topologies involve the conceptof routes. Unlike each of the previoustopologies, messages sent on a meshnetwork can take any of severalpossible paths from source todestination. (Recall that even in aring, although two cable pathsexist, messages can only travel in onedirection.) Some WANs, most notablythe Internet, employ mesh routing. 56. TYPES OF NETWORKLAN WAN MAN 57. SOCIAL & ETHICAL ISSUES