1. Slide 1.1 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. An Introduction to Object-Oriented Systems Analysis and Design with UML and the Unified Process McGraw-Hill, 2004 Stephen R. Schach srs@vuse.vanderbilt.edu

2. Slide 1.2 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. CHAPTER 1 INTRODUCTION TO INFORMATION SYSTEMS

3. Slide 1.3 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter Overview l Categories of Information Systems l Traditional Information System Development –The Requirements Phase –The Analysis Phase –The Design Phase –The Implementation Phase –The Maintenance Phase –Retirement

4. Slide 1.4 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter Overview (contd) l Why There Is No Planning Phase l Why There Is No Testing Phase l Why There Is No Documentation Phase l Systems Analysis and Design l Maintenance Information Technology Professionals

5. Slide 1.5 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Jethro’s Boot Emporium l Automated reordering system l Jethro’s formula for predicting future trends l The formula works perfectly … l … at first

6. Slide 1.6 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Definitions l Artifact –Component l System –Set of artifacts that achieve some outcome l Information system –System that achieves a business outcome l Computerized information system –COTS (commercial off-the-shelf) package –Custom information system

7. Slide 1.7 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Custom Information System l Stakeholders –Client –Users –Developers

8. Slide 1.8 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. COTS Software l Shrinkware l Clickware l Stakeholders –Users –Developers l Enterprise Resource Planning (ERP) system –Examples: PeopleSoft, SAP

9. Slide 1.9 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Traditional Information System Development l Information system life cycle –The way that software is constructed l Six traditional phases

10. Slide 1.10 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Overview of the Traditional Phases l Requirements phase –Find the client’s requirements –Draw up the requirements document l Analysis phase –Draw up the specification document –Draw up the project management plan l Design phase –Determine the modules –Determine algorithms and data structures for each module

11. Slide 1.11 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Overview of the Traditional Phases (contd) l Implementation phase –Translate the modules into a programming language –Integrate the modules l Maintenance phase –Modify the system »Remove any remaining faults »Extend the system in some way l Retirement –The system no longer provides a useful service

12. Slide 1.12 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Why There Is No Planning Phase l We cannot plan until we have accurate, detailed information l There are three types of planning activities: –There is preliminary planning at the start of the project –The project management plan is drawn up after the specifications have been approved by the client –Management monitor the plan all through the project

13. Slide 1.13 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Why There Is No Planning Phase (contd) l Planning activities are carried out all through the life cycle  There is no separate planning phase

14. Slide 1.14 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Why There is No Testing Phase l Checking the information system just before delivery is much too late l An information system must be checked continually  There is no separate testing phase

15. Slide 1.15 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Why There Is No Documentation Phase l The documentation must be complete, correct, and up to date at all times –Personnel turnover in the information system industry –Performing a phase requires the documentation from the previous phase l Testing activities require documentation l Maintenance activities require documentation  There is no separate documentation phase

16. Slide 1.16 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Systems Analysis and Design l The word analysis is used in two different ways: –Analysis: Phase 2 –Systems analysis: Phases 1 and 2 l The term systems analyst is also used in two different ways –Responsible for Phases 1 and 2; or –Responsible for Phases 1, 2, and 3 l The second usage is more common –That is the way systems analyst is used in this book

17. Slide 1.17 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Maintenance l Bad information systems are thrown away l Good information systems are maintained for many years

18. Slide 1.18 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. The Financial Implications of Maintenance l For very $1 spent on development, at least $2 is spent on maintenance

19. Slide 1.19 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Maintenance Activities l There are three main maintenance activities: l Corrective maintenance –Fixing faults l Perfective maintenance –Adding functionality l Adoptive maintenance –Making changes because the environment changes –(Enhancement: Corrective + Perfective maintenance)

20. Slide 1.20 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Software Organizations l Software –Computer program (code) + documentation l Many organizations produce software –They employ systems analysts l Some organizations outsource

21. Slide 1.21 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Software Organizations l Organizations like Microsoft and Oracle produce software –As a primary product l Organization like General Motors and General Electric produce software –But not as a primary product

22. Slide 1.22 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Typical Information Systems Division

23. Slide 1.23 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Information Technology Professionals l Technical positions –Programmer –Programmer/analyst –Systems analyst l Alternative career path –Business analyst –Acquire programming skills  Systems analyst

24. Slide 1.24 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Information Technology Professionals (contd) l Management hierarchy –Manager for information system development –Vice-President for information system development –Chief information officer (CIO) –Chief executive officer (CEO)

25. Slide 1.25 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Essential Systems Analyst Skills l Technical skills l Communication skills l Programming knowledge l Sufficient technical knowledge to able to consult –Database administrator –Network administrator –Systems programmers –Software engineers

26. Slide 1.26 Copyright © 2004 by The McGraw-Hill Companies, Inc. All rights reserved. Ethical Issues l Systems analysts must be ethical in every way l Example: Excerpt from the Code of Ethics of AITP “I acknowledge: That I have an obligation to my College or University, therefore, I shall uphold its ethical and moral principles. That I have an obligation to my employer whose trust I hold, therefore, I shall endeavor to discharge this obligation to the best of my ability, to guard my employer's interests, and to advise him or her wisely and honestly. I accept these obligations as a personal responsibility and as a member of this Association. I shall actively discharge these obligations and I dedicate myself to that end.”