Construct, Deliver, and Maintain Systems Projects

1
Chapter 14

• Construct, Deliver, and Maintain Systems
  Projects

2
Objectives for Chapter 14

• The sequence of events that constitute the
  in-house development phase of the SDLC
• The tools used to improve the success of system
  construction and delivery activities (CASE tools
  PERT and Gantt charts)
• The distinction between the structured and
  object-oriented design approaches
• Multi-level DFDs in the design of business
  processes
• The different types of system documentation and
  the purposes they serve
• The role of accountants in the construct and
  delivery of systems
• The advantages and disadvantages of the
  commercial software option, the decision-making
  process used to select commercial software

3
Systems Development Life Cycle
Business Needs and Strategy
Legacy Situation
Business Requirements
1. Systems Strategy - Assessment - Develop
Strategic Plan
FeedbackUser requests for New Systems
System Interfaces, Architecture and User
Requirements
High Priority Proposals undergo Additional Study
and Development
2. Project Initiation - Feasibility Study -
Analysis - Conceptual Design -
Cost/Benefit Analysis
FeedbackUser requests for System Improvements
and Support
Selected System Proposals go forward for Detailed
Design
3. In-house Development - Construct -
Deliver
4. Commercial Packages - Configure - Test -
Roll-out
New and Revised Systems Enter into Production
5. Maintenance Support - User help desk -
Configuration Management - Risk Management
Security
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 include
• lower initial cost
• shorter implementation time
• better controls
• rigorous testing by the vendor
• risk
• must ensure that the user gets a package that
  adequately meets his or her needs and is
  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 3

• In-House Development

8
Up to 25 of all systems projects fail! Why?

• 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

systems developer
end user
9
Prototyping

• Prototyping is a technique for providing users a
  preliminary working version of the system.
• It is built quickly and relatively inexpensively
  with the intention it will be modified.
• As the 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
Identify Conceptual User Specifications
Change Prototype Per User Feedback
Develop Prototype into Finished System
Present Prototype to Users
Obtain User Feedback
Develop Prototype
Discard Prototype and Develop System
Under Traditional SDLC Procedures
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
Project Evaluation and Review Technique (PERT)
Deliver Phase
Construct Phase
2
7
A 3 Weeks
Purchase Equipment
Install and Test Equipment
Prepare Documentation
D 2 Weeks
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
Test System
F 5 Weeks
Code Programs
4
5
8
PERT charts show the relationship among key
activities that constitute the construct and
delivery process.
15
Gantt Chartrepresents time horizontally and
activities vertically
Purchase Equipment
Design Data Model
Design Process
Install and Test Equipment
Code Programs
Test Programs
Create Data Structures
Convert Data Files
Test System
Current Point in Time
Prepare Documentation
Train Personnel
Cut Over to New System
Budgeted Actual
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
Project Week
16
The Structured Design Approach

• is 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 DFD 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.

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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

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Characteristics of an Inventory Object
Attributes
Quantity on Hand
Part Number
Description
Reorder Point
Order Quantity
Inventory
Object
Operations
Review Quantity
Reduce
Reorder
Replace
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Classes and Instances

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

Inventory
Object Class
Instance
Water Pump
Wheel Bearing
Alternator
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

• This stage follows a logical sequence of events
• data model the business process and design
  conceptual views
• design the normalized database tables
• design the physical user views (output and input
  views)
• develop the process modules
• specify the system controls
• perform a system walkthrough

23
Data Modeling

• Data Modeling is the task of formalizing the data
  requirements of the business process as a
  conceptual model.
• The primary tool is the ER diagram which is used
  to depict the entities or data objects in the
  system.
• Each entity in an ER diagram is a candidate for a
  conceptual user view that must be supported by
  the database.

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Physical User Views Output Views

• Output is the information produced by the system
  to support user tasks and decisions.
• Output attributes
• relevant
• summarization
• except orientation
• timely
• accurate
• complete
• concise

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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.

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Physical User Views Input Views

• Data input views are used to capture the relevant
  facts about the resources, events, and agents
  involved in business process transactions.
• Input may be either
  hard copy input documents or
  electronic input.

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Designing Hard Copy Input

• Items to Consider
• How will the document be handled? What quality
  paper?
• 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.

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Designing Electronic Input

• Input may be from either hardcopy or electronic

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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

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Designing the Process Component

• This phase begins with the DFDs produced in the
  general design phase.
• The first task is to decompose the existing DFDs
  to a degree of detail that will serve as the
  basis for creating structure diagrams.
• The structure diagrams will provide the
  blueprints for writing the actual program modules.

31
Data Flow Diagrams (DFDs)

• DFDs are used to represent multiple levels of
  detail.
• Context-level DFDs are used to present an
  overview model of the business activities and the
  primary transactions processed by the system.
• It does not include a detailed definition of data
  files and specific procedures.

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Lower-Level DFD for an AP Process
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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)

34
Design 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
• This step 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.

35
System Design Walkthrough

• This step is performed by the development team to
  ensure the design is free from conceptual errors
  that could become programmed into the final
  system.
• Some firms may use a quality assurance group to
  perform the task. This is an independent group
  of programmers, analysts, users, and internal
  auditors.

36
Program Application Software

• If the organization intends to develop software
  in-house, then a programming language must be
  selected, such as
• procedural languages or 3GLs (COBOL)
• event-driven languages
  (Visual Basic)
• object-oriented languages
  (Java)

37
The Modular Approach to Programming

• Promotes programming efficiency since modules can
  be both programmed and tested independently
• Promotes maintenance efficiency since small
  modules are easier to analyze and change
• Promotes greater control since they are less
  likely to contain material errors of fraudulent
  logic

38
Deliver the SystemTesting

• Programs must be thoroughly tested before they
  are implemented.
• Individual modules should be tested with test
  data containing both good and bad data. All
  logic procedures should be tested.
• After the individual modules have been tested,
  the entire system should tested as a whole.

39
Deliver the SystemDocumenting

• Documentation describes how the system works and
  should be made 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

40
Deliver the SystemConverting the Databases

• This is the transfer of data from its current
  form to the format or medium required by the new
  system.
• Data conversion is risky and must be carefully
  controlled by the following precautions
• validation - old database must be inspected
  before conversion
• reconciliation - after the conversion, the new
  database must be reconciled against the original
• backup - copies of the original files must be
  kept as backup against discrepancies in the
  converted data

41
Deliver the SystemConverting the Databases

• Three approaches
• Cold turkey cutover - the firm switches to the
  new system on a particular day and simultaneously
  terminates the old system.
• This is the riskiest approach.
• Phased cutover - modules are implemented in a
  piecemeal fashion.
• The risk of a devastating failure can be reduced.
• Parallel operation cutover - the old system and
  new system are run simultaneously.
• This is the safest, yet costliest, approach.

42
Deliver the SystemPost-Implementation Review

• The objective is to measure the success of the
  system and of the process after the dust has
  settled. Want to assess
• system design adequacy
• accuracy of time, cost, and benefit estimates
• This information can provide feedback to improve
  future systems development projects.

43
Deliver the SystemThe Role of Accountants

• Most system failures are due to poor designs 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

44
Phase 4

• Commercial Packages

45
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

46
Trends in Commercial Packages

• Turnkey systems are completely finished and
  tested systems that are ready for implementation.
• Backbone systems provide a basic system structure
  on which to build.
• Vendor-supported systems are custom-developed and
  maintained by a vendor for a customer.
• ERP systems are difficult to classify since they
  have characteristic of all of the above.

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Pros and Cons of Commercial Packages

• Advantages
• decreased implementation time
• decreased cost
• reduced probability of program errors
• Disadvantages
• reduced independence - the customer is dependent
  on the vendor for maintenance
• less flexibility in system
• greater difficulty in modifying the system as
  needs change over time

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Four Steps in Choosing a Commercial Package

1. Analyze needs and develop detailed specifications
   of the system requirements.
2. Send out the request for proposals to all
   prospective vendors to serve as a comparative
   basis for initial screening.
3. Gather the facts about each vendors system using
   multiple sources and techniques.
4. Analyze the findings and make a final selection.

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Phase 5

• Maintenance and
• Support

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Maintenance and Support

• Approximately 80 of the life and costs of the
  SDLC
• Can be outsourced or done with in-house resources
• User support is a critical aspect of maintenance.
  Can be facilitated by
• knowledge management - method for gathering,
  organizing, refining, and disseminating user
  input
• group memory - method for collecting user input
  for maintenance and support

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The Iceberg Effect