Chapter 14 Construct, Deliver, and Maintain Systems Projects

1. Chapter 14Construct, Deliver, and Maintain Systems Projects

2. Objectives for Chapter 14 Be able to identify the sequence of events that constitutes the in-house development phase of SDLC. Be familiar with tools used to improve the success of systems construction and delivery activities including prototyping, CASE tools, and the use of PERT and Gantt charts. Understand the distinction between structured and object-oriented design approaches. Understand the use of multi-level DFDs in the design of business processes. Be familiar with the different types of systems documentation and the purposes they serve. Recognize the role of accountants in the construction and delivery of systems. Understand the advantages and disadvantages of the commercial software option and be able to discuss the decision-making process used to select commercial software.

3. System Development Life Cycle Figure 14-1

4. Overview of Phases 3, 4 and 5 • Phase 3. In-House Development • appropriate when organizations have unique information needs • steps include: • analyzing user needs • designing processes and databases • creating user views • programming the applications • testing and implementing the completed system

5. Overview of Phases 3, 4 and 5 • Phase 4. Commercial Packages • When acceptable, most organizations will seek a pre-coded commercial software package. • advantages: • lower initial cost • shorter implementation time • better controls • rigorous testing by the vendor • risks: • must adequately meet end users’ needs • compatible with existing systems

6. Overview of Phases 3, 4 and 5 • Phase 5. Maintenance and Support • acquiring and implementing the latest software versions of commercial packages • making in-house modifications to existing systems to accommodate changing user needs • may be relatively trivial, such as modifying an application to produce a new report, or more extensive, such as programming new functionality into a system

7. Phase 3Systems Strategy

8. Why Up to 25% of All Systems Projects Fail • Poorly specified systems requirements • communication problems • time pressures • Ineffective development techniques • paper, pencils, templates, erasers instead of software tools, such as CASE • Lack of user involvement in systems development

9. Prototyping • A technique for providing a preliminary working version of the system • Built quickly and relatively inexpensively with the intention it will be modified • End users work with the prototype and make suggestions for changes. • A better understanding of the true requirements of the system is achieved.

10. Prototyping Techniques Figure 14-2

11. Computer-Aided Software Engineering (CASE) CASE technology involves the use of computer systems to build computer systems. CASE tools are commercial software products consisting of highly integrated applications that support a wide range of SDLC activities.

12. Uses of CASE Tools Define user requirements Create physical databases from conceptual user views Produce system design specifications Automatically generate program code Facilitate the maintenance of programs created by both CASE and non-CASE techniques

13. CASE Spectrum of Support Tools for the SDLC

14. PERT Chart for In-House Development Project Deliver Phase Construct Phase 2 7 A = 3 Weeks Purchase Equipment Install and Test Equipment D = 2 Weeks Prepare Documentation H = 3 Weeks K = 3 Weeks Train Personnel B = 4 Weeks E = 5 Weeks I = 3 Weeks Design Data Model Create Data Structures Convert Data Files 1 3 6 9 Test Programs L = 4 Weeks G = 3 Weeks Design Process Cut Over to New System C = 4 Weeks J = 4 Weeks F = 5 Weeks Test System Code Programs 4 5 Figure 14-4 8 PERT charts show the relationship among key activities that constitute the construct and delivery process.

15. Gantt Chart Figure 14-5

16. Structured Design Approach A disciplined way of designing systems from the top down Starts with the “big picture” of the proposed system and gradually decomposes it into greater detail so that it may be fully understood Utilizes data flow diagrams (DFDs) and structure diagrams

17. Object-Oriented Design Approach It builds information systems from reusable standard components or objects. Once created, standard modules can be used in other systems with similar needs. A library of modules can be created for future use.

18. Elements of the Object-Oriented Approach • Objects: equivalent to nouns • vendors, customers, inventory, etc. • Attributes: equivalent to adjectives • part number, quantity on hand, etc. • Operations: equivalent to verbs • review quantity on hand, reorder item

19. Characteristics of an Inventory Object Figure 14-8

20. Classes and Instances An object class is a logical grouping of individual objects that share the same attributes and operations. An object instance is a single occurrence of an object within a class.

21. Inheritance Inheritance means that each object instance inherits the attributes and operations of the class to which it belongs. Object classes may also inherit from other object classes.

22. Systems Design • Follows a logical sequence of events: • model the business process and design conceptual views • design normalized database tables • design physical user views (output and input views) • develop process modules • specify system controls • perform system walkthroughs

23. Data Modeling • Formalizes the data requirements of the business process as a conceptual model • Entity-relationship diagram (ERD) • the primary tool for data modeling • used to depict the entities or data objects in the system • Each entity in an ERD is a candidate for a conceptual user view that must be supported by the database.

24. Normalization • User views in the data modelmust be supported by normalized database tables. • Normalization of database tables: • A process of organizing tables so that entities are represented unambiguously • Eliminates data redundancies and associated anomalies • Depends on the extent to which the data requirements of all users have been properly specified in the data model • REA modeling facilitates normalization by identifying entities at their most fundamental levels • The resulting databases will support multiple user views • Described in more detail in chapter 9.

25. Physical User Views: Output Views • -timeliness • -accuracy • -completeness • -conciseness • Output is the information produced by the system to support user tasks and decisions. • Output attributes: -relevance -summarization -exception orientation

26. Output Reporting Techniques • Different users prefer different styles of output… • tables, matrices, charts, and graphs • …and modes of output. • hard copy vs. display screen. • Systems designers must identify these styles and provide output in the desired style.

27. Physical User Views: Input Views • Input views are used to capture the relevant facts in business processes and transactions (e.g., via REA model): • Resources • Events • Agents • Input may be either hard copy input documents or electronic input.

28. Designing Hard Copy Input • Items to Consider: • How will the document be handled? • How long will the form be stored and in what type of environment? • How many copies are required? • What size form is necessary? • Non-standard form can cause printing and storage problems.

29. Designing Electronic Input Input may be from either hardcopy or electronic Figure 14-14

30. Data Entry Devices Point-of-sale terminals Touch screens Mouse Magnetic ink character recognition devices Optical character recognition devices Voice and touch-tone recognition devices

31. Designing Process Modules Begins with the DFDs produced in the general design phase First, decompose the existing DFDs to a degree of detail that will serve as the basis for creating structure diagrams Structure diagrams provide the blueprints for writing the actual program modules

32. Data Flow Diagrams (DFDs) • Used to represent multiple levels of detail. • Can represent system physically or logically • Context-level DFDs represent an overview of the business activities and the primary transactions processed by the system. • Do not include detailed definitions of data files and specific procedures. • Decompose high-level DFDs into more detailed lower-level DFDs.

33. DFD for Purchases and Cash Disbursements System Figure 14-15

34. Lower Level DFD for AP Process I.4 Figure 14-16

35. The Modular Approach • Each module performs a single task. • Correctly designed modules possess two attributes: • loosely coupled - low amounts of exchange of data between modules • strongly cohesive - small number of tasks performed in each module

36. Designing System Controls • The last step in the detailed design phase • Need to consider: • computer processing controls • data base controls • manual controls over input to and output from the system • operational environment controls • Allows the design team to review, modify, and evaluate controls with a system-wide perspective that did not exist when each module was being designed independently

37. Systems Walkthrough • Usually performed by the development team • Ensure that design is free from conceptual errors that could become programmed into the final system • Some firms use a quality assurance (QA) group to perform this task. • An independent group of programmers, analysts, users, and internal auditors

38. Program Application Software • If the organization intends to develop software in-house, then a programming language must be selected: • procedural languages or 3GLs COBOL • event-driven languages Visual Basic • object-oriented languages Java

39. The Modular Approach to Programming • Promotes programming efficiency • modules can be both programmed and tested independently • Promotes maintenance efficiency • small modules are easier to analyze and change • Promotes greater control • modules are less likely to contain material errors of fraudulent logic

40. Deliver the System:Testing • Programs must be thoroughly tested before being implemented. • All logic procedures should be tested. • Test individual modules with test data containing both “good” and “bad” data. • After testing individual modules, the entire system should tested as a whole.

41. Deliver the System:Documenting • Describes how the system works • Documentation should be provided for: • designers and programmers - comment lines in programs, system flowcharts, and program flowcharts • operator documentation - run manuals • user documentation - instructions on how to use the system, tutorials, and help features • accountants and auditors - all of the above as well as document flowcharts

42. Deliver the System:Converting the Databases • The transfer of data from its current form to the format or medium required by the new system • Control risks with the following procedures: • validation – inspect old database before conversion • reconciliation – reconcile the new converted database against the original • backup - keep copies of the original files against discrepancies in the converted data

43. Deliver the System:Converting the Databases Three data conversion cutover approaches: • Cold turkey - switch to the new system all at once and simultaneously terminate the old system. • riskiest approach • Phased - modules are implemented in a piecemeal fashion. • reduces risk of a devastating failure • Parallel operation - the old system and new system are run simultaneously for a while. • safest, yet costliest, approach

44. Deliver the System:Post-Implementation Review • Objective: measure the success of the new system. • do after initial problems have been addressed • Assess: • system design adequacy • accuracy of time, cost, and benefit estimates • Provides feedback to improve future systems development projects, including changes to the current system

45. Deliver the System:The Role of Accountants • Most system failures are due to poor design and improper implementation. • Accountants should provide their expertise to help avoid inadequate systems by: • providing technical expertise for financial reporting requirements • specifying documentation standards for auditing purposes • verifying control adequacy in accordance with SAS 78

46. Phase 4Commercial Packages

47. The Purchase of Commercial Systems Packages • Four factors have stimulated the growth of commercial software: • relatively low cost • prevalence of industry-specific vendors • growing demand by small businesses • trend toward downsizing and distributed data processing

48. Trends in Commercial Packages • Turnkey systems - completely finished and tested systems ready for implementation • Backbone systems - provide a basic system structure on which to build. • Vendor-supportedsystems - customized and maintained by a vendor for a customer • ERP systems - difficult to classify since they have characteristic of all of the above. • See chapter 11 for more details on ERP systems.

49. Pros and Cons of Commercial Packages • Advantages: • decreased implementation time • decreased cost • reduced probability of program errors • Disadvantages: • dependent on the vendor for maintenance • less flexibility in system • greater difficulty in modifying the system as needs change over time

50. Four Steps in Choosing a Commercial Package • Analyze needs and develop detailed specifications of the system requirements. • Send out the request for proposals to all prospective vendors to serve as a comparative basis for initial screening. • Gather the facts about each vendor’s system using multiple sources and techniques. • Analyze the findings and make a final selection.