Information Systems and Systems Development | CIS 101, Study notes of Computer Science

Download Information Systems and Systems Development | CIS 101 and more Study notes Computer Science in PDF only on Docsity! Chapter 12 Information Systems and Systems Development What Is an Information System? System: collection of elements and procedures that interact to accomplish a goal Elements are people, computers, buildings, cables, etc. Information system: generates information about organization Business School System development: process of designing and implementing a new or modified system The process has a structure; it is not ad hoc 1-2 Who Uses Information Systems? Executive managers: strategic decisions CIO, college president, army general, etc. Decide to make a new product, open a new plant, etc. Middle managers: tactical decisions Decide to reschedule a project, hire staff, etc. Operational managers: operational decisions Decide to run a program a 1 AM instead of midnight, decide to use computer A instead of B, etc. Nonmanagement workers: on-the-job decisions Types of Information Systems Office (OAS) Automates office tasks. The hardware and software on desktops. Transaction Processing (TPS) Processes business transactions, e.g., billing Management Information (MIS) Provides business information, e.g., budget information Decision Support (DSS) Used by executive management to analyze data and make decisions Expert Makes decisions using information programmed from human experts Design and Manufacturing (CAD/CAM) Used to design and manufacture products 3-4 Decision Support Systems, Cont'd Provides the advice that would be expected from a human expert Knowledge base: database containing facts provided by human experts and rules the system should use to make decisions based on those facts Inference engine: program that applies the rules to the knowledge base, to reach decisions Is only as good as: Knowledge base Inference engine The information provided by the user Expert Systems 9-10 Expert Systems, Cont'd Design and Manufacturing Systems Computer-aided design (CAD) Used to design products Replacement for drafting boards and blueprints Product is drawn in full detail and in 3 dimensions Computer-aided manufacturing (CAM) Used manufacture products Example: robots on car assembly line Replacement for manual labor 11-12 Responsibility for System Development Information systems (IS) department is responsible for developing and maintaining computer systems Business analyst: Determines the business requirements for a system Usually not a technical person Systems analyst: Determines the technical solution for business requirements A technical person Programmers Operations personnel Responsibility for System Development, Cont'd Each system has a project manager Responsible for budget, schedule, staffing, and satisfying business requirements Each system has a team consisting of other IS staff and "end users", the people who will use the system Development work may be "outsourced" - done by vendors, not IS staff Use growing, primarily due to cost Offshore offsourcing = outsourced to another country Captive offshoring = companies setting up their own facilities in another country Has security, privacy, and morale issues 13-14 System Design Phase System design: determine technical solution and obtain a system model Done by system analyst(s) Model describes, in words and diagrams, how the system works System flowcharts Input/output designs Data dictionary May include a more detailed cost/benefit analysis Product(s): documents describing the technical solution and model System Design Phase, Cont'd 19-20 System Acquisition Phase System acquisition: acquire the system by either: Purchasing off-the-shelf Developing in house If purchase: Develop Request for Proposal (RFP) or Request for Quote (RFQ) and send to vendors Evaluate vender bids Select vendor If develop: Start system development (Chapter 13) Product(s): RFPs and RFQs System Implementation Phase System implementation: make the system operational Direct conversion (old system deactivated; new system installed) Parallel conversion (both old and new operated for a period of time) Phased conversion (new system implemented by module) Pilot conversion (new system installed at a pilot location initially) A very major issue with large systems Product(s): Test data, test results, etc. 21-22 System Implementation Phase, Cont'd System Maintenance Phase System maintenance: keep the system running and improve it as necessary An ongoing-process When a major change is needed, the SDLC is used again Typically more money and time spent on this phase than any other Some systems used for 30+ years Product(s): Problem Reports (PRs) to fix system 23-24