Introductions to systems analysis and design

1. Introductions to systems analysis and design

2. Chapter Guide • Information system concept概念 • System components • How business uses information systems • The systems development life cycle周期 • Computing personnel计算人员

3. Concepts and components: concepts The Concept of a System 'A group of things or parts forming a whole' (Heinemann, Australian Dictionary) ' A set of procedures程序used to accomplish a specific result' 'A set of interrelated, interacting components that function together ...to achieve a specific result'一组相互关联，相互作用的部件共同作用，以达到特定的结果 (Powers, Cheney & Crow - 'Structured Systems Development')

4. Concepts and components: concepts A few general system ideas • 1.An information systemcan be seen as an example of the general system concept • 2.A system that interacts with other systems in its  environment is known as an open system. • 3.A system that has the ability to change in response to  changes in its environment is known as an adaptive   system. • 4.All systems are a subsystem of a larger system --- systems within systems • 5.A system is more than simply the sum of its parts , ie   a system produces results that cannot be provided  by each part acting alone. • 6.An organization or businesscan also be seen as a system • Systems pervade our lives. For instance, our respiratory system, manufacturing system, payroll systems, transport systems, gambling systems, the system - 'you can't beat the system'.

5. Concepts and components: concepts Business Systems e.g. factory, motel, university, department of social security, etc. Complex organization systems are broken down into subsystems. e.g. a manufacturing company system. To facilitate decision-making , meet Legislative requirements, provide information To external bodies, Accurate, timely information is needed

6. Concepts and components: concepts An Information System Is a subsystem of a business system, which manages business data?  May it be manual or computerized? E.g. 1165ASMITHJOHN127834355012NEWSTFLORAHILL Sales Report as of: 3rd March 2003           ------------------------------------------------- Number            Name                  Address 1165               John Smith          12 New St Flora Hill                                                    3550                              (Department    Marketing)                                 Total Sales:   $1278.43 Data? Information?

7. Hardware • Programs • Data • Procedures程序 • personnel人员 input output feedback Concepts and components: components Information System Components Physical level Moore’s law System software Application software Functions, Processes Activities(tasks) Table,database (end) users (internal/ external), Skilled professionals All 5 components are essential to an efficient system.

8. Developing an information system Computer Personnel • Management staff管理人员 • Operational staff业务人员 System users 3. Systems Analyst系统分析员 4. Programmer 5. DBA System constructor and maintainer系统的施工和维护人员

9. Administrative staff Systems categories: How Business Uses Information Systems 执行 Executive Information System Decision Support System Operational System操作系统 Office System办公系统 Traditional classification Based on the user group the system served

10. A Modern Approach to Systems Analysis and Design Modern Approach Client/Server Platform Browser/Server Platform For company, they can purchase IS such as enterprise-wide system of SAP or Oracle; Or they can develop IS in-house; So, you need to know the role of SA

11. Role of System Analyst The role of SA The primary role of a system analyst is to :pp11 • Four skills • analytical • technical • managerial • interpersonal How to get an information system for an organization?

12. How to get an IS for an organization Several options • Customized by an IT service firm • Buy the system off the shelf • Implement enterprise-wide system from a company • Obtain open source software • Use in-house staff to develop • Outsourcing So the source of software : 1.IT service firm; 2.Packaged software providers 3.Vendors of enterprise-wide solution software; 4.Open-source software; 5.in-house development

13. Developing an information system Developing A CIS E.g. Space shuttle, bookings system, DOS, Police Department criminal records. should produce the CIS ... • On time • Within budget • So that it satisfies the user's needs. • Problems • System may be incredibly complex - too complex for one person to comprehend all parts. • User may not be able to express what they require.

14. Developing an information system Developing A CIS cont… Solution Systems Development Life Cycle: • A structured ordered method for developing a (computerized) information system. • Breaks the development of a system down into small manageable parts • Each part is organized and simple

15. Structured analysis method The systems development life cycle SDLC generally comprises 6 phases阶段: 1. System planning规划 2. Systems Analysis 3. Systems Design 4. Systems Development开发 5. Systems Implementation and Evaluation实施与评价 6. Maintain 维护Systems

16. Structured analysis method SDLC Definition (Whitten, Bentley & Barlow 1994) A Systems Development Life Cycle系统开发生命周期(SDLC) is a process by which systems analysts, software engineers, programmers, and end-users build information systems and computer applications. (Lavette 1985) The systems development life cycle is an organized approach used in organizations to develop an information system. (Shelly, Cashman & Adamski 1991) Organized and structured methodology for developing, implementing, and installing a new or modified computer information system,

17. Systems request Evaluate request System change System improvement Preliminary investigation(Y/N?) conclusions SDLC: Phase 1 Phase 1. system planning • (Establish the user's problem) • Project requests initiate from users (workers or managers).   • Evaluate requests - compatibility with organization’s objectives, technical and economic feasibility. • Choose one request for further investigation. • Prepare project management plan.

18. SDLC: Phase 2 Phase 2. Systems Analysis • (Establish the user's requirements) • Analyze present system. • Determine improvements and describe new requirements in detail. • Outline any constraints on the new system. • Output is System Requirement document. • Perform further feasibility study.

19. SDLC: Phase 3 Phase 3. System Design • Design data files. • Design input, output and user interfaces. • Application software design. • Outline design of each module. • Plan management of programming, testing and debugging. • output is systems design specification

20. SDLC: Phase 4 Phase 4. Systems development • (Construction) • Choose programming language. • Code, test and debug module at a time. • Acceptance test by users and external evaluators. • Prepare final version of user documentation.

21. SDLC: Phase 5 Phase 5. Systems Implementation and Evaluation • Decide on conversion method. • Set-up hardware, create or convert data files. • Refine software. • Review if system still meeting performance targets.

22. SDLC: Phase 6 Phase 6. Maintain Systems • Accommodate any minor changes in business environment. • Enhance the usefulness or augment scope of system in response to user requests. • SDLC is only a framework - activities tailored to specific project. Assumptions have to be made.  Project can be called off at any stage as feasibility fails.

23. Test yourself • What are the five key components of information systems? • How are business information systems identified? • What are the phases of the systems development life cycle?