Semoga Bermanfaat :)

1. Accounting Information Systems, 6th
edition
James A. Hall
COPYRIGHT © 2009 South-Western, a division of Cengage Learning. Cengage Learning and South-Western
are trademarks used herein under license

2. Objectives for Chapter 14
The sequence of events that constitutes the in-house
development phase of SDLC
Tools used to improve the success of systems construction and
delivery activities: CASE tools; PERT and Gantt charts
Distinction between structured and object-oriented design
approaches
Multi-level DFDs in the design of business processes
Types of systems documentation and the purposes they serve
The role of accountants in the construction and delivery of
systems
The advantages and disadvantages of the commercial software
option

3. Systems Development Life Cycle
1. Systems Strategy
- Assessment
- Develop Strategic Plan
1. Systems Strategy
- Assessment
- Develop Strategic Plan
2. Project Initiation
- Feasibility Study
- Analysis
- Conceptual Design
- Cost/Benefit Analysis
2. Project Initiation
- Feasibility Study
- Analysis
- Conceptual Design
- Cost/Benefit Analysis
3. In-house Development
- Construct
- Deliver
3. In-house Development
- Construct
- Deliver
4. Commercial Packages
- Configure
- Test
- Roll-out
4. Commercial Packages
- Configure
- Test
- Roll-out
5. Maintenance & Support
- User help desk
- Configuration Management
- Risk Management & Security
5. Maintenance & Support
- User help desk
- Configuration Management
- Risk Management & Security
SSystemystem Interfaces, ArchitectureInterfaces, Architecture
and Uand Userser RRequirementsequirements
BBusinessusiness RRequirementsequirements
High Priority Proposals undergoHigh Priority Proposals undergo
Additional Study and DevelopmentAdditional Study and Development
FeedbackFeedback::
User requests for New SystemsUser requests for New Systems
Selected System ProposalsSelected System Proposals
go forward for Detailedgo forward for Detailed
DesignDesign
New and RevisedNew and Revised
Systems Enter intoSystems Enter into
ProductionProduction
Business Needs and
Strategy
Legacy Situation
FeedbackFeedback::
User requests for SystemUser requests for System
Improvements and SupportImprovements and Support

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

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. Identify
Conceptual
User
Specifications
Develop
Prototype
Present
Prototype
to Users
Obtain
User
Feedback
Change
Prototype
Per User
Feedback
Develop
Prototype
into Finished
System
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. 1
2
7
3
4
6
8
9
Purchase Equipm
ent
Install and
Test Equipm
ent
Design Data Model Create Data Structures
5
Design Process
Code Programs
TestPrograms
Prepare Docum
entation
Convert Data Files
Test System
TrainPersonnel
Cut Over
to New
System
A
=
3 W
eeks
B = 4 Weeks
C
=
4 W
eeks
D
=
2 W
eeks
E = 5 Weeks
F = 5 Weeks
G
=3W
eeks
H
=
3
W
eeks
I = 3 Weeks
J =
4 W
eeks
L
=
4 W
eeks
K
=
3W
eeks
Construct Phase Deliver Phase
Project Evaluation and Review
Technique (PERT)
PERT charts show the relationship among key activities
that constitute the construct and delivery process.

15. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Project Week
Purchase Equipment
Design Data Model
Install and Test Equipment
Design Process
Code Programs
Test Programs
Create Data Structures
Prepare Documentation
Convert Data Files
Test System
Cut Over to New System
Train Personnel
CurrentPointinTime
Budgeted
Actual
Gantt Chart
represents time horizontally and activities vertically

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. Part Number Description
Quantity
on Hand Reorder Point Order Quantity
Inventory
Reduce
Review
Quantity
Reorder Replace
Attributes
Object
Operations

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.
Inventory
Wheel Bearing Alternator Water Pump
Object
Class
Instance

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 model must 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 that 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
Output is the information produced by the system
to support user tasks and decisions.
Output attributes:
-relevant
-summarization
-except orientation
-timely
-accurate
-complete
-concise

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. 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.
Physical User Views:
Input Views

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

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
Decompose high-level DFDs into more
detailed lower-level DFDs
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

33. Lower-Level DFD for an AP Process

34. 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

35. 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

36. 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

37. 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

38. 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

39. 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.

40. 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
Deliver the System:
Documenting

41. 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
Deliver the System:
Converting the Databases

42. 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 awhile
safest, yet costliest, approach
Deliver the System:
Converting the Databases

43. 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
Deliver the System:
Post-Implementation Review

44. 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. 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

47. 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-supported systems - 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

48. 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

49. 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 vendor’s system
using multiple sources and techniques.
4. Analyze the findings and make a final
selection.

51. Maintenance and Support
Approximately 80% of the life and costs of SDLC
Can be outsourced or done in-house resources
End user support is a critical aspect of
maintenance that 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

52. The Iceberg Effect