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Chapter 14

Construct, Deliver, and Maintain Systems Projects

Accounting Information Systems, 5th editionJames A. Hall

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SDLC major phases

1. Systems strategy2. Project initiation3. In-house development4. Commercial packages5. Maintenance & support

Chapter 14

Chapter 13

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

System Interfaces, Architecture and User Requirements

Business Requirements

High Priority Proposals undergo Additional Study and Development

Feedback:User requests for New Systems

Selected System Proposals go forward for Detailed Design

New and Revised Systems Enter into Production

Business Needs and Strategy

Legacy Situation

Feedback:User requests for System Improvements and Support

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Ch14 Ch14

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Overview of Phases 3, 4 and 5

Phase 3 - In-House Development appropriate when organizations have

unique information needs steps include:

analyzing user needsdesigning processes and databasescreating user viewsprogramming the applicationstesting 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 costshorter implementation timebetter controlsrigorous testing by the vendor

risks:must adequately meet end users’ needsmust 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 3In-house Development

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3 problems that account for most system failures…

1. Poorly specified systems requirementscommunication problemstime pressures

2. Lack of user involvement in systems

development/selection 3. Ineffective development

techniques(for internally developed systems)

systemsdeveloper

enduser

PrototypingProvides preliminary working version

of the systemBuilt 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.

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PERT charts

Used to show relationship among key activities of a systems project

Probably used more for in-house development (than commercial software acquisition)

A

DG

B

C

F

H

I

Purch

ase E

quipm

ent

Install and Test Equipment

Design Data Model Create Data Structures

E

Design Process

Code Programs Test

Prog

ram

s

Prepare

Doc

umen

tation

Convert Data Files

Test System

Train Personnel

Cut Over

to N

ew Syste

m

A-D 3

Wee

ks

A-B 4 Weeks

A-C 4 Weeks

D-F 2 Weeks

B-F 5 Weeks

C-E 5 Weeks E-F

3 W

eeks

F-G 3

Wee

ks

F-I 3 Weeks

F-H 4 Weeks

H-I 4 W

eeks

G-I 3 Weeks

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.

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 systemEach 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 ControlsThe last step in the detailed design phaseNeed 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

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SY STE M

The Delivery

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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 documentationAccountant/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

Phase 4Commercial Packages

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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 analysis2. 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.

Phase 5Maintenance and Support

Maintenance and Support

Approximately 80% of the life and costs of SDLC

Can be outsourced or done in-houseEnd 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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