1. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1 Managing Information Technology 6 th Edition CHAPTER 9 BASIC INFORMATION SYSTEMS CONCEPTS

2. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 2 The Systems View What is a system? A set of interrelated components that must work together to achieve some common purpose System The collection of IT, procedures, and people responsible for the capture, movement, management, and distribution of data and information Information System

3. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 3 THE SYSTEMS VIEW 1.Boundary 2.Environment 3.Inputs 4.Outputs 5.Components 6.Interfaces 7.Storage Seven key system elements

4. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 4 THE SYSTEMS VIEW Seven key system elements Delineation of which elements are within the system and which are outside 1. Boundary Everything outside the system 2. Environment

5. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 5 THE SYSTEMS VIEW Seven key system elements Resources from the environment that are consumed and manipulated within the system 2. Inputs Resources or products provided to the environment by the activities within the system 3. Outputs 4.

6. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 6 THE SYSTEMS VIEW Seven key system elements Activities or processes within the system that transform inputs into intermediate forms or that generate system outputs Components can be viewed as subsystems 5. Components

7. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 7 THE SYSTEMS VIEW Seven key system elements The place where two components or the system and its environment meet or interact 6. Interfaces Holding areas used for the temporary and permanent storage of information, energy, materials, and so on 7. Storage

8. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 8 THE SYSTEMS VIEW Examples of System Components from Payroll Time cards, vouchers Inputs Paychecks, W-2 Forms Outputs Calculate total pay, subtract deductions Components Match time cards to employees, sort paychecks by department Interfaces Employee benefits, Pay rates Storage

9. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 9 THE SYSTEMS VIEW Some system components can be viewed as systems with their own sets of interrelated components and are called subsystems Hierarchical decomposition is the process of breaking a system down into successive levels of subsystems Five important goals of hierarchical decomposition: 1.Cope with system complexity 2.Analyze or change only part of the system 3.Design and build each subsystem at different times 4.Direct the attention of a target audience 5.Allow components to operate more independently Component Decomposition

10. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 10 THE SYSTEMS VIEW One useful framework for examining how information systems fit into organizational systems is based on the Leavitt diamond Four fundamental components in an organization are linked – People – Organizational structure – Information Technology – Business Processes Organizations as systems

11. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 11 THE SYSTEMS VIEW Leavitt Diamond – If one is component is changed, the others will likely be affected as well – For example, new software may have the following effects: People have to be retrained Business processes need to be redesigned Organizational structures must be modified Organizations as systems

12. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 12 THE SYSTEMS VIEW IT leaders understand that changes in information systems affect the entire organizational system One process used in developing new systems that takes into account the systems view is Systems Analysis and Design (SA&D) Two key principles: – Choose an appropriate scope – Logical before physical Systems analysis and design

13. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 13 THE SYSTEMS VIEW SA&D has five key design principles Two key principles stem from key systems characteristics: 1.Choose an appropriate scope Selecting the boundary for the IS greatly influences complexity and success of the project 2.Logical before physical You must know what an IS is to do before you can specify how a system is to operate Systems Analysis and Design

14. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 14 THE SYSTEMS VIEW SA&D has five key design principles The other three principles are problem-solving steps: 3.A problem is actually a set of problems and an appropriate strategy is to keep breaking down a problem into smaller, more manageable problems 4.A single solution is not usually obvious to all stakeholders, so alternative solutions representing all parties should be generated before a final solution is selected 5.The problem and your understanding of it could change; thus a staged approach that incorporates reassessments and incremental commitment to a solution is best Systems Analysis and Design

15. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 15 Business Processes In the 1990s many organizations changed from a more functional approach to a more process-oriented approach to better compete globally Experts urged companies to radically change the way they did business by starting with a “clean slate” and utilizing IT “Don’t automate; obliterate!” - Michael Hammer

16. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 16 These changes became known as business process reengineering Business Processes Radical business redesign initiatives that attempt to achieve dramatic improvements in business processes by questioning the assumptions, or business rules, that underlie the organization’s structures and procedures Business process reengineering (BPR)

17. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 17 Business Processes How IT Enables New Ways to Work

18. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 18 Business Processes Six Key Principles for Redesigning Business Processes Organize business processes around outcomes, not tasks Assign those who use the output to perform the process Integrate information processing into the work that produces the information Create a virtual enterprise by treating geographically distributed resources as though they were centralized Lick parallel activities instead of integrating their results Have people who do the work make all the decisions, and let controls built into the system monitor the process

19. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 19 Processes and Techniques Three phases of information system development: 1.Definition: end users and systems analysts conduct a multistep analysis of the current business operations and the information system or systems in the area of concern 2.Construction: designing, building, and testing of a system that satisfies the requirements developed in the Definition phase 3.Implementation: install the new system, which often involves converting data and procedures from an old system Systems development life cycle (SDLC)

20. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 20 Procedural-oriented – Most common – Include data-oriented, sequential, process-oriented activities Object-oriented – Newer approach – Often used for GUIs and multimedia applications Structured Techniques Tools to document system needs, requirements, functional features, dependencies, and design decisions Structured Techniques

21. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 21 Procedural oriented techniques describe what you have, define what you want, and describe how you will make it so Different techniques are used to create the following three models: 1.As-Is 2.Logical To-Be 3.Physical To-Be Structured Techniques

22. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 22 1.As-Is Model Must identify existing processes, external participants, other databases or applications, and inputs and outputs 2.Logical To-Be High-level model of a nonexistent new system Identifies processes and data Does not identify who does activity, where accomplished, or type of hardware or software Describes “what” rather than “how” 3.Physical To-Be Requires technology expertise to map the logical requirements to available technology Structured Techniques

23. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 23 Structured Techniques Context Diagram – Positions the system as a whole with regard to other entities and activities with which it interacts Techniques for the As-Is Model

24. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 24 Structured Techniques Data Flow Diagram (DFD) – Shows the flows of information through the system – These consist of four symbols representing: External Entity Data Flow Process Data Store Techniques for the Logical To-Be Model

25. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 25 PROCESSES AND TECHNIQUES

26. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 26 Structured Techniques Data Dictionary/Directory – Used to define data elements Techniques for the Logical To-Be Model

27. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 27 Structured Techniques Entity-Relationship Diagram (E-R Diagram or ERD) – Used to define relationships among entities Techniques for the Logical To-Be Model

28. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 28 Structured Techniques Draft Layouts – Represents user interface design Techniques for the Physical To-Be Model

29. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 29 – Primary advantage is object reuse – Can enable quick prototyping Structured Techniques Object-Oriented (O-O) Techniques

30. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 30 – Encapsulation – An object contains data and related operations – Allows loosely coupled modules and reuse – Inheritance – One class of objects can inherit characteristics from others – Polymorphism – The ability to treat child objects the same as parent objects (i.e. call methods exactly the same) Structured Techniques Core Object-Oriented Concepts

31. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 31 – A set of standardized techniques and notations for O-O analysis and design There are several types of UML diagrams used to design systems including – Use-case diagram – Class diagram Structured Techniques Unified Modeling Language (UML)

32. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 32 UML Use Case Diagram – Represents the interaction of users with the system Unified Modeling Language (UML)

33. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 33 UML Class Diagram – Represents each object’s attributes, methods, and relationships with other objects Unified Modeling Language (UML)

34. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 34 Information Systems Controls All businesses face security risks and only a small percentage of those risks involve IT IT can be used to mitigate some business risk through the addition of controls There are three types of control mechanisms 1.Management policies 2.Operating procedures 3.Auditing function

35. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 35 Information Systems Controls Controls can be built into the information system itself throughout the SDLC

36. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 36