Chapter 14
Construct, Deliver, and
Maintain Systems
Projects
Accounting Information Systems,
5th edition
James A. Hall
1
SDLC major phases
1.
2.
3.
4.
5.
Systems strategy
Project initiation
In-house development
Commercial packages
Maintenance & support
Chapter 13
Chapter 14
2
Systems Development Life Cycle
Business Needs and
Strategy
Legacy Situation
Business Requirements
1. Systems Strategy
- Assessment
- Develop Strategic Plan
System Interfaces, Architecture and
User Requirements
Ch13
Feedback:
User requests for New Systems
High Priority Proposals undergo
Additional Study and Development
2. Project Initiation
- Feasibility Study
- Analysis
- Conceptual Design
- Cost/Benefit Analysis
Ch13
Feedback:
User 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
Ch14
New and Revised Systems
Enter into Production
5. Maintenance & Support
- User help desk
- Configuration Management
- Risk Management & Security
Ch14
Ch14
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
Overview of Phases 3, 4 and 5
Phase 4 - Commercial Packages
when acceptable, most organizations will seek
commercial software package
advantages:
lower initial cost
shorter implementation time
better controls
rigorous testing by the vendor
risks:
must adequately meet end users’ needs
must be compatible with existing systems
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
Phase 3
In-house
Development
3 problems that account for
most system failures…
1. Poorly specified systems
requirements
communication problems
time pressures
systems
2. Lack of user involvement developer
in systems development/selection
3. Ineffective development
techniques
(for internally developed systems)
end
user
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Prototyping
Provides 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.
Computer-Aided Software
Engineering (CASE)
CASE technology uses 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.
PERT charts
Used to show relationship among key
activities of a systems project
Probably used more for in-house
development (than commercial software
acquisition)
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Project Evaluation and Review
Technique (PERT)
Deliver Phase
Construct Phase
D
A-B 4 Weeks
Design Data Model
A
B-F 5 Weeks
Create Data Structures
B
F-I 3 Weeks
Convert Data Files
F
I
C
E
H
PERT charts show the relationship among key activities that
constitute the construct and delivery process.
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 (not necessary to
study DFDs)
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
Data Modeling
Formalizes data requirements of the
business process as conceptual model
Entity-relationship diagram (ERD)
primary tool for data modeling
used to depict the entities or data objects in
system
Each entity in ER diagram is a candidate
for a conceptual user view that must be
supported by database.
Normalization
User views in 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
The resulting databases will support multiple user views
More detail in chapter 9 about data
normalization
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
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.
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
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
The Delivery
SY
M
T
E
S
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Delivering a system
Appropriate for commercial software or
in-house development
Test entire system
Document the system
Designer/Programmer documentation (in-house)
Operator documentation (more centralized than
distributed)
User documentation
Accountant/Auditor documentation
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Conversion of databases
Appropriate for commercial software
or in-house development
Transfer of data from old system to new
system
Validate data before conversion
Reconcile data after conversion
Keep backup copies of old data!
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Converting to New System
Three approaches:
Cold turkey cutover (“Big Bang”) - firm
switches to new system on particular day and
simultaneously terminates old system. Riskiest
approach.
Phased cutover - modules are implemented in
piecemeal fashion. Risk of devastating failure
can be reduced.
Parallel cutover - old system and new system
are run simultaneously. Safest, yet costliest,
approach.
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Role of Accountants in
Construct & Deliver Phases
Accountant should:
Provide technical expertise re:
GAAP, GAAS, SEC regulations, SoX,
IRS code.
Specify documentation standards
Verify control adequacy
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Phase 4
Commercial
Packages
4. Commercial Software
Four factors have stimulated growth of
commercial software:
relatively low cost
prevalence of industry-specific vendors
growing demand by small businesses
trend of organizational downsizing and
distributed data processing
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Types of Commercial Software
Turnkey systems: completely finished and
tested systems -- ready for implementation.
Backbone systems: provide basic system
structure on which to build.
Vendor-supported systems: custom-developed
and maintained by vendor for customer.
ERP systems are difficult to classify because they
have characteristics of all of the above.
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Commercial Software
Advantages
Implementation time
Cost
Reliability
Disadvantages
Dependence on vendors
Need for customized systems
Maintenance
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Steps in Choosing a
Commercial Package
1. Needs analysis
2. Send out Request for Proposals (RFP) to
prospective vendors to serve as comparative
basis for initial screening.
3. Gather facts about each vendor’s system using
multiple sources and techniques.
4. Analyze findings and make final selection.
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Phase 5
Maintenance
and Support
Maintenance and Support
Approximately 80% of the life and costs of SDLC
Can be outsourced or done in-house
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
The Iceberg Effect
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