romney ab.az.ch20
TRANSCRIPT
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C HAPTER 20
Systems Design,
Implementation, and
Operation
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INTRODUCTION
Questions to be addressed in this chapter
include:
What are the activities that take place in the
conceptual design phase of the systems developmentlife cycle (SDLC)?
What activities take place in the physical systems
design phase?
What happens during the systems implementationand conversion process?
What activities occur in the systems operation and
maintenance process?
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INTRODUCTION
Accountants must understand the entire systemsdevelopment process, because they areinvolved in several ways: Helping to specify their needs.
As members of the development team.
As auditors after the fact.
Accountants also help keep the project on track
by: Evaluating and measuring benefits. Measuring costs.
Ensuring the project stays on schedule.
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INTRODUCTION
Effective systems analysis and design
can ensure that developers:
Correctly define the business problem. Design the appropriate solution.
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INTRODUCTION
The crucial phases of the SDLC include:
Systems analysis to define the new systems
requirements (discussed in Chapter 18).
The phases discussed in this chapter, which
include:
Conceptual systems design
Physical systems design Systems implementation and conversion
Operation and maintenance
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INTRODUCTION
The crucial phases of the SDLC include:
Systems analysis to define the new systems
requirements (discussed in Chapter 18).
The phases discussed in this chapter, which
include:
Conceptual systems design
Physical systems design Systems implementation and conversion
Operation and maintenance
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CONCEPTUAL SYSTEMS DESIGN
In the conceptual sys tems designphase, a general framework is created forimplementing user requirements and
solving the problems identified in theanalysis phase.
The three main steps are:
Evaluate design alternatives. Prepare design specifications.
Prepare the conceptual systems designreport.
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Systems
Analysis
Prepare
Design
Specifications
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
Prepare
Conceptual Systems
Design Report
Evaluate
Design
Alternatives
Conceptual
Systems
Design
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Systems
Analysis
Prepare
Design
Specifications
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
Prepare
Conceptual Systems
Design Report
Evaluate
Design
Alternatives
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CONCEPTUAL SYSTEMS DESIGN
Evaluating design alternatives
There are many design decisions that must
be made. For example:
Should a document be hard-copy or sent by EDI?
Should the company use a large centralized
mainframe or some form of distributed processing?
What form should data entry take, e.g., keyboard,
optical character recognition, POS devices?
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CONCEPTUAL SYSTEMS DESIGN
Also, there are many ways to approach the
systems development process:
Packaged software
In-house development End-user development
Outsourcing
The company also chooses between:
Modifying or enhancing existing software
Replacing existing software
Reengineering its business processes
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CONCEPTUAL SYSTEMS DESIGN
The design team should identify a variety ofdesign alternatives and evaluate each withrespect to: How well it meets organizational and system
objectives How well it meets user needs
Whether it is economically feasible
Its advantages and disadvantages
The steering committee evaluates thealternatives.
Click here to view some of the designconsiderations and alternatives from Table 20-1in your textbook.
Design Considerations
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Systems
Analysis
Prepare
Design
Specifications
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
Prepare
Conceptual Systems
Design Report
Evaluate
Design
Alternatives
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CONCEPTUAL SYSTEMS DESIGN
Prepare design specifications
Once a design has been selected, the
project team develops the conceptualdesign speci f icat ionsfor the following
elements:
Output
Because output is what goes to the user and the
system must be designed to meet user needs, the
output specifications are prepared first.
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CONCEPTUAL SYSTEMS DESIGN
Prepare design specifications
Once a design has been selected, the
project team develops the conceptualdesign speci f icat ionsfor the following
elements:
Output
Data storage
How will data be stored to produce the desired
outputs?
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CONCEPTUAL SYSTEMS DESIGN
Prepare design specifications
Once a design has been selected, the
project team develops the conceptualdesign speci f icat ionsfor the following
elements:
Output
Data storage
Input What types of data must be entered to produce the
desired outputs?
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CONCEPTUAL SYSTEMS DESIGN
Prepare design specifications
Once a design has been selected, theproject team develops the conceptual
design speci f icat ionsfor the followingelements:
Output
Data storage Input
Processing procedures and operations
How will data be processed and in what sequenceto produce the desired outputs?
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Systems
Analysis
Prepare
Design
Specifications
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
Prepare
Conceptual Systems
Design Report
Evaluate
Design
Alternatives
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CONCEPTUAL SYSTEMS DESIGN
Prepare the conceptual systems design
report
A conceptual systems design repor tis
prepared at the end of the conceptual designphase to:
Guide physical system design activities.
Communicate how management and userinformation needs will be met.
Help the steering committee assess system
feasibility.
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CONCEPTUAL SYSTEMS DESIGN
The main component is a description of one or
more recommended system designs. This
description contains:
The contents of each output, database, and input. Processing flows and the relationships among
programs, files, inputs, and outputs.
Hardware, software, and resource requirements.
Audit, control, and security processes andprocedures.
A discussion of assumptions or unresolved problems
that might affect the final design.
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INTRODUCTION
The crucial phases of the SDLC include:
Systems analysis to define the new systems
requirements (discussed in Chapter 18).
The phases discussed in this chapter, which
include:
Conceptual systems design
Physical systems design Systems implementation and conversion
Operation and maintenance
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PHYSICAL SYSTEMS DESIGN
During the physical systems design phase, thecompany determines how the conceptual AISdesign is to be implemented. The broad, user-oriented requirements of conceptual
design are translated into detailed specifications usedto code and test computer programs.
Phases include: Designing output
Creating files and databases
Designing input Writing computer programs
Developing procedures
Building in controls
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Systems
Analysis
Conceptual
Systems
Design
Output
Design
Implementation
and
Conversion
Operation
and
Maintenance
File and DB
Design
Input
Design
Program
Design
Proce-dures
Design
Controls
Design
Physical
Systems
Design
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Systems
Analysis
Conceptual
Systems
Design
Output
Design
Implementation
and
Conversion
Operation
and
Maintenance
File and DB
Design
Input
Design
Program
Design
Proce-dures
Design
Controls
Design
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PHYSICAL SYSTEMS DESIGN
Output design
The objective of output design is to
determine the nature, format, content,and timing of printed reports,
documents, and screen displays.
Requires cooperation between users and
designers.
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Who will use it and why?
When is it needed?
What decisions will it facilitate?
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Output medium
Paper
Screen
Voice response
Diskette
Microfilm
Other
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Output medium
Output format Should select the format thatclearly conveys the most
information.
Could be:
Table Narrative
Graphic
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Output medium
Output format
Pre-printed Should paper output be onpreprinted form and/or
turnaround document?
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Output medium
Output format
Pre-printed
Location Where is the output to be
sent?
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Output medium
Output format
Pre-printed
Location
Access Who should be able toaccess hard-copy and
screen output?
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Output medium
Output format
Pre-printed
Location
Access
Detail
Lengthy output should be preceded by an
executive summary and a table of contents.
Headings and legends organize data and
highlight important items.
Detailed info goes in an appendix.
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PHYSICAL SYSTEMS DESIGN
Important design considerations include:
Use of the output
Output medium
Output format
Pre-printed
Location
Access
Detail
Timeliness
How often should the output be produced?
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PHYSICAL SYSTEMS DESIGN
Outputs usually fit into one of the following
four categories:
Scheduled reports
Have pre-specified content and format.
Are prepared on a regular basis.
Examples:
Weekly sales analysis
Monthly financial statements
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PHYSICAL SYSTEMS DESIGN
Outputs usually fit into one of the following
four categories:
Scheduled reports
Special-purpose analysis reports
No pre-specified content and format.
Typically prepared in response to a
management request. Example:
Analysis of impact of a government
mandate on profitability
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PHYSICAL SYSTEMS DESIGN
Outputs usually fit into one of the following
four categories:
Scheduled reports
Special-purpose analysis reports
Triggered exception reports
Have pre-specified content and format.
Prepared only in response to abnormalconditions, i.e., the trigger.
Example:
Cost overruns
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PHYSICAL SYSTEMS DESIGN
Outputs usually fit into one of the following
four categories:
Scheduled reports
Special-purpose analysis reports
Triggered exception reports
Demand reports
Have pre-specified content and format.
Prepared only on request.
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PHYSICAL SYSTEMS DESIGN
AIS developers prepare sample outputs
and users evaluate them to ensure they
are complete, relevant, and useful.
Modifications are made as needed to ensure
acceptability.
Many organizations require users to sign off
on these documents before proceedingthrough the SDLC.
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Systems
Analysis
Conceptual
Systems
Design
OutputDesign
Implementation
and
Conversion
Operation
and
Maintenance
File and DBDesign
InputDesign
ProgramDesign
Proce-dures
Design
ControlsDesign
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PHYSICAL SYSTEMS DESIGN
File and database design
Various company segments need to store data in
compatible formats so that data can be shared across
units.
Important file and database design considerations
include:
Storage medium Hard drive
Disk
Diskette
CD
Tape
Paper
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PHYSICAL SYSTEMS DESIGN
File and database design
Various company segments need to store data in
compatible formats so that data can be shared across
units.
Important file and database design considerations
include:
Storage medium
Processing mode Manual
Batch Real time
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PHYSICAL SYSTEMS DESIGN
File and database design
Various company segments need to store data in
compatible formats so that data can be shared across
units.
Important file and database design considerations
include:
Storage medium
Processing mode
Maintenance What procedures are needed to
effectively maintain the data?
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PHYSICAL SYSTEMS DESIGN
File and database design
Various company segments need to store data in
compatible formats so that data can be shared across
units.
Important file and database design considerations
include:
Storage medium
Processing mode
Maintenance
Size How many records and how big are they?
How fast are they expected to grow?
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PHYSICAL SYSTEMS DESIGN
File and database design
Various company segments need to store data in
compatible formats so that data can be shared across
units.
Important file and database design considerations
include:
Storage medium
Processing mode
Maintenance
Size
Activity level
What portion of records are added or
deleted each year? What portion needs to be updated?
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Systems
Analysis
Conceptual
Systems
Design
OutputDesign
Implementation
and
Conversion
Operation
and
Maintenance
File and DBDesign
InputDesign
ProgramDesign
Proce-dures
Design
ControlsDesign
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PHYSICAL SYSTEMS DESIGN
Input design
Systems designers must identify the
different types of data input and optimal
input methods.
There are two principal types of data
input:
Forms
Computer screens
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium Keyboard
OCR
MICR
POS terminal
EDI
Voice input
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Where do data originate?
Computer
Customer
Remote location
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Input format What format captures the data with
the least effort or cost?
Source or turnaround document
Screen
Source data automation
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Input format Input type What is the nature of the data?
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Input format Input type
Volume How much data are to be entered?
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Input format Input type
Volume
Personnel
What functions and expertise do the dataentry operators have?
Is additional training necessary?
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Input format Input type
Volume
Personnel
Frequency How often is data to be entered?
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Input format Input type
Volume
Personnel
Frequency
Cost
How can costs be minimized withoutadversely affecting efficiency and
accuracy?
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PHYSICAL SYSTEMS DESIGN
Considerations in input design include:
Input medium
Input source
Input format Input type
Volume
Personnel
Frequency
Cost
Error detection and correction
What errors are possible? How can they be detected and corrected?
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PHYSICAL SYSTEMS DESIGN
Forms design
Although input is evolving toward source data
automation, forms design is still important.
Following are important principles fordesigning new forms and evaluating existing
ones:
General considerations
Preprint as much data as possible.
Use appropriate weight and grade of paper.
Use bold type, double-thick lines, and shading to
highlight different parts of the form.
Use a standard size and one that is consistent with
requirements for filing, binding, or mailing.
If mailed to external parties, position the address for
placement in a window envelope. Have copies of the form printed in different colors to
facilitate accurate distribution.
Include clear instructions for completing the form.
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PHYSICAL SYSTEMS DESIGN
Forms design
Although input is evolving toward source data
automation, forms design is still important.
Following are important principles fordesigning new forms and evaluating existing
ones:
General considerations
Introductory section of form
Main body of form
Group together logically related information
(e.g., info about the customer, info about
the product).
Provide sufficient room to record each item. Order the data items consistent with the
sequence in which the data is likely to be
gathered.
Use codes and check-offs in places where
standardized explanations are likely.
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PHYSICAL SYSTEMS DESIGN
Forms Design
Although input is evolving toward source data
automation, forms design is still important.
Following are important principles fordesigning new forms and evaluating existing
ones:
General considerations
Introductory section of form
Main body of form
Conclusion section of form
Provide space for: Recording final disposition of the form.
Approval signatures.
Dates of approval and final disposition.
A dollar or numeric total.
Clearly indicate the distribution of
each form.
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PHYSICAL SYSTEMS DESIGN
Computer screens are most effective when the following
principles are used:
Organize the screen for quick, accurate, and complete entry
of the data.
Minimize input by retrieving as much as possible fromthe system.
Example: If the customer number is entered, retrieve his
name/address data from the system.
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PHYSICAL SYSTEMS DESIGN
Computer screens are most effective when the following
principles are used:
Organize the screen for quick, accurate, and complete entry of
the data.
Enter data in the same order it appears on the document.
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PHYSICAL SYSTEMS DESIGN
Computer screens are most effective when the followingprinciples are used:
Organize the screen for quick, accurate, and complete entry of
the data.
Enter data in the same order it appears on the document. Complete the screen from left to right and top to bottom,
grouping logically related data together.
Design the screen so users can jump from one data entry
location to another or use a single key to go directly to
screen locations.
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PHYSICAL SYSTEMS DESIGN
Computer screens are most effective when the followingprinciples are used:
Organize the screen for quick, accurate, and complete entry of
the data.
Enter data in the same order it appears on the document. Complete the screen from left to right and top to bottom,
grouping logically related data together.
Design the screen so users can jump from one data entry
location to another or use a single key to go directly to screen
locations. Make it easy to correct mistakes.
Use clear and explicit error messages that are consistent
on all screens.
Provide a help feature for online assistance.
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PHYSICAL SYSTEMS DESIGN
Computer screens are most effective when the followingprinciples are used:
Organize the screen for quick, accurate, and complete entry of
the data.
Enter data in the same order it appears on the document. Complete the screen from left to right and top to bottom,
grouping logically related data together.
Design the screen so users can jump from one data entry
location to another or use a single key to go directly to screen
locations. Make it easy to correct mistakes.
Avoid clutter by restricting the amount of data on one
screen.
Limit the number of menu options on a single screen.
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Systems
Analysis
Conceptual
Systems
Design
OutputDesign
Implementation
and
Conversion
Operation
and
Maintenance
File and DBDesign
InputDesign
ProgramDesign
Proce-dures
Design
ControlsDesign
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PHYSICAL SYSTEMS DESIGN
Program design
Program development is one of the most time-
consuming activities in the SDLC.
A struc tured prog ramm ingprocess should be
followed:
With structured programming, programs should be
subdivided into small, well-defined modules to reduce
complexity and enhance reliability and modifiability.
Modules should interact with a control module rather thanwith each other.
To facilitate testing and modification, each module should
have only one entry and exit point.
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PHYSICAL SYSTEMS DESIGN
To improve software quality, organizations
should develop programming standards (rules
for writing programs).
Contributes to consistency among programs. Makes them easier to read and maintain.
Consider doing structured program walk-
throughs to find incorrect logic, errors,
omissions, or other problems.
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PHYSICAL SYSTEMS DESIGN
Program preparation time may range from a fewdays to a few years, depending on complexity.
Though accountants need not be programmers,
they should understand how software is created. The following slides discuss the eight steps for
developing software and where these steps take
place in the SDLC.
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PHYSICAL SYSTEMS DESIGN
STEP ONE: Determine userneeds.
Occurs during the systems analysis
stage of the SDLC.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
STEP TWO: Develop anddocument a plan.
Occurs during the conceptual design
phase and the beginning of physical
design.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
STEP THREE: Write the programcode.
Design in increasing levels of detail,
known as hierarch ical program
design.
Begun during systems design and
completed during systems
implementation.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
STEP FOUR: Test the program code.
Debuggingis discovering and
eliminating program errors.
Desk checkinghappens after a
program is coded and involves avisual and mental review to discover
programming errors.
Programs are tested for logic errors
using test data that simulates bothvalid transactions and all possible
error conditions.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
Large programs are often testedin three stages:
Individual program modules.
The linkages between the moduleand the control module.
The interfaces between the
program being tested and other
application programs.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
Errors need to be found as soonas possible in the development
process.
Errors discovered late cost 801000% more to fix than those
found early.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
STEP FIVE: Document theprogram.
Documentation explains how
programs work and helpscorrect and resolve errors.
Includes flowcharts, record
layouts, E-R diagrams, REA
data models, narrativedescriptions of the system, etc.,
organized in a manual.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
STEP SIX: Train program users.
Often uses the program
documentation.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
STEP SEVEN: Install the system.
-All components are brought
together, and the company
begins to use the system.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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PHYSICAL SYSTEMS DESIGN
STEP EIGHT: Use and modifythe system.
Prog ram maintenanceis a
response to any factors thatrequire program revision.
Includes requests for: New or revised reports.
Changes in input, file content, orvalues such as tax rates.
Error detection and correction.
Conversion to new hardware.
SystemsAnalysis
Conceptual
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
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Systems
Analysis
Conceptual
Systems
Design
OutputDesign
Implementation
and
Conversion
Operation
and
Maintenance
File and DBDesign
InputDesign
ProgramDesign
Proce-
dures
Design
ControlsDesign
S C S S S S G
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PHYSICAL SYSTEMS DESIGN
Procedures design Individuals who interact with a newly-
designed AIS need procedures to cover: Input preparation
Transaction processing
Error detection and correction
Controls
Reconciliation of balances
Database access
Output preparation and distribution
Computer operator instructions
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PHYSICAL SYSTEMS DESIGN
Procedures may take the form of:
System manuals
User instruction classes
Training materials
Online help screens
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PHYSICAL SYSTEMS DESIGN
The procedures may be written by:
Development teams;
Users; or
Teams representing both groups.
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Systems
Analysis
Conceptual
Systems
Design
OutputDesign
Implementation
and
Conversion
Operation
and
Maintenance
File and DBDesign
InputDesign
ProgramDesign
Proce-
dures
Design
ControlsDesign
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PHYSICAL SYSTEMS DESIGN
Controls design Improperly controlled input, processing, and
database functions produce information ofquestionable value.
Controls must be built into an AIS to ensureits effectiveness, efficiency, and accuracy.These controls should: Minimize errors.
Detect and correct errors when they do occur.
Accountants play a vital role in this area.
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity Are all interactions valid?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity
Authorization
Are input, processing, storage, and
output activities authorized by the
appropriate managers?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity
Authorization
Accuracy Is input verified to ensure accuracy?
What controls ensure that data is not
lost when passing between processing
activities?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity
Authorization
Accuracy
Security
Is the system protected against:
Unauthorized physical and logical access to preventimproper use, alteration, destruction, or disclosure of
information and software?
Theft of system resources?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity
Authorization
Accuracy
Security
Numerical control
Are documents pre-numbered to prevent errors orintentional misuse and to detect when documents are
missing or stolen?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity
Authorization
Accuracy
Security
Numerical control
Availability Is the system available as set forth in agreements?
Can users enter, update, and retrieve data during those
times?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity
Authorization
Accuracy
Security
Numerical control
Availability Maintainability
Can the system be modified without affecting system
availability, security, and integrity? Are only authorized, tested, and documented changes
made to the system and data?
Are resources available to manage, schedule, document,
and communicate changes to management and
authorized users?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include:
Validity
Authorization
Accuracy
Security
Numerical control
Availability Maintainability
Integrity
Is processing complete, accurate, timely, and
authorized?
Is it free from unauthorized or inadvertentmanipulations?
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PHYSICAL SYSTEMS DESIGN
Important control concerns that must beaddressed include: Validity
Authorization
Accuracy Security
Numerical control
Availability
Maintainability Integrity
Audit trail
Can data be traced from source to output and viceversa?
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PHYSICAL SYSTEMS DESIGN
Physical systems design reportAt the end of the physical design phase, a
physica l sys tems design repo r tis
prepared, summarizing what wasaccomplished.
This report serves as the basis for
managements decision whether to proceed to
implementation.
INTRODUCTION
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INTRODUCTION
The crucial phases of the SDLC include: Systems analysis to define the new systems
requirements (discussed in Chapter 18).
The phases discussed in this chapter, whichinclude:
Conceptual systems design
Physical systems design
Systems implementation and conversion
Operation and maintenance
SYSTEMS IMPLEMENTATION AND
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CONVERSION
Systems implementation Systemsimplementat ionis the process of
installing hardware and software andgetting the AIS up and running.
Phases include: Developing a plan
Preparing the site
Installing and testing hardware and software
Selecting and training personnel
Completing documentation
Testing the system
Systems
Analysis
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Conceptual
SystemsDesign
Physical
Systems
Design
Operation
and
Maintenance
Prepare Site;
Install and Test
Hardware
Select and TrainPersonnel
System
Implementation
and
Conversion
Implementation
Planning
Complete
Documentation
TestSystem
Conversion
Systems
Analysis
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Conceptual
SystemsDesign
Physical
Systems
Design
Operation
and
Maintenance
Prepare Site;
Install and Test
Hardware
Select and TrainPersonnel
Implementation
Planning
Complete
Documentation
TestSystem
Conversion
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CONVERSION
Implementation planning An imp lementat ion planconsists of:
Implementation tasks
Expected completion dates
Cost estimates Specification of the person(s) responsible for each task
The plan specifies when the project should becomplete and operational.
The implementation team should identify risk
factors that decrease the likelihood of successfulimplementation, and the plan should contain astrategy for coping with each of the risks.
SYSTEMS IMPLEMENTATION AND
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CONVERSION
AIS changes may require adjustments to thecompanys organizational structure,
including:
Creation of new departments.
Elimination or downsizing of existing
departments.
Changes even in the data processing department.
Systems
Analysis
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Conceptual
SystemsDesign
Physical
Systems
Design
Operation
and
Maintenance
Prepare site;
Install and Test
hardware
Select and TrainPersonnel
Implementation
Planning
Complete
Documentation
TestSystem
Conversion
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CONVERSION
Site preparation A large computer may require changes such as:
New electrical outlets
Data communications facilities
Raised floors Humidity controls
Special lighting
Air-conditioning
Security measures, such as:
Fire protection
Emergency power supply
Space for equipment, storage, and offices
SYSTEMS IMPLEMENTATION AND
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CONVERSION
Site preparation is a lengthy process andshould begin well ahead of the installation
date.
Systems
Analysis
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Conceptual
SystemsDesign
Physical
Systems
Design
Operation
and
Maintenance
Prepare Site;
Install and Test
Hardware
Select and TrainPersonnel
Implementation
Planning
Complete
Documentation
TestSystem
Conversion
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SYSTEMS IMPLEMENTATION AND
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CONVERSION
When training is insufficient, the company willnot achieve the expected return on investment.
The hidden cost is that users will turn to theircoworkers who have mastered the system for
help. Results in: Less productive coworkers Increased costs
Effective training includes: Hardware and software skills
Orientation to new policies and operations
The training should be scheduled just beforesystems testing and conversion.
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CONVERSION
Types of training include: Technical training from vendors
Self-study manuals
Computer-aided instruction Videotape presentations
Role-playing
Case studies Experimenting with the AIS under the
guidance of experienced users
Systems
Analysis
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Conceptual
SystemsDesign
Physical
Systems
Design
Operation
and
Maintenance
Prepare site;
Install and Test
Hardware
Select and Train
Personnel
Implementation
Planning
Complete
Documentation
Test
System
Conversion
SYSTEMS IMPLEMENTATION AND
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CONVERSION
Three types of documentation must beprepared for new systems: Development documentation
Describes the AIS and includes: A system description.
Copies of output, input, file, and database layouts.
Program flowcharts.
Test results.
User acceptance forms.
SYSTEMS IMPLEMENTATION AND
CO S O
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CONVERSION
Three types of documentation must beprepared for new systems: Development documentation
Operations documentation
Includes:
Operating schedules.
Files and databases accessed.
Equipment, security, and file retention requirements
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CONVERSION
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CONVERSION
Three types of documentation must beprepared for new systems: Development documentation
Operations documentation User documentation
Teaches users how to operate the AIS.
Includes a procedures manual and training materials.
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CONVERSION
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CONVERSION
Test the system Inadequate system testing has contributed to the
failure of systems.
All of the following should be given a trial run in
realistic circumstances. Documents and reports User input
Operating and control procedures
Processing procedures
Computer programs Should also test:
Capacity limits
Backup and recovery procedures
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CONVERSION
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CONVERSION
Three common forms of testing include: Walk-throughs
Step-by-step reviews of procedures or program logic.
Attended by the development team and users early in systemdesign.
Focus is on organization:
Input
Files
Outputs
Data flows
Subsequent walk-throughs are attended by programmers.
Address logical and structural aspects of program code.
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CONVERSION
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CONVERSION
Three common forms of testing include: Walk-throughs
Processing test transactions
Determines whether the program operates asdesigned.
Requires both valid and erroneous data.
The correct response for each test should be
specified in advance.
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CONVERSION
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CONVERSION
Three common forms of testing include: Walk-throughs
Processing test transactions
Acceptance tests Uses copies of real transactions and files
rather than hypothetical ones.
Users develop acceptance criteria.
Then make final decision whether to accept.
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CONVERSION
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CONVERSION
Three common forms of testing include: Walk-throughs
Processing test transactions
Acceptance tests
Even software purchased from an
outside vendor must be tested
thoroughly before installation.
Systems
Analysis
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Conceptual
SystemsDesign
Physical
Systems
Design
Operation
and
Maintenance
Prepare site;
Install and test
hardware
Select and Train
Personnel
Implementation
Planning
Complete
documentation
Test
system
Conversion
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CONVERSION
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CONVERSION
Systems conversion Convers ionis the process of changing from the old
AIS to the new.
Many elements must be converted, including:
Hardware
Software
Data files
Procedures
The process is complete when the new AIS hasbecome a routine, ongoing part of the system.
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CONVERSION
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CONVERSION
Conversion approaches Four conversion approaches are used to
change from an old to a new system:
Direct conversion Parallel conversion
Phase-in conversion
Pilot conversion
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CONVERSION
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CONVERSION
Conversion approaches Four conversion approaches are used to
change from an old to a new system:
Direct conversion Parallel conversion
Phase-in conversion
Pilot conversion
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CONVERSION
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CONVERSION
Direct conversion Immediately terminates the old AIS when the
new one is introduced.
Appropriate when: The old AIS has no value; or
The new AIS is so different that comparisons
between the two are meaningless.
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CONVERSION
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CONVERSION
Main advantage to direct conversion: Its inexpensive
Main disadvantage:
It provides no backup AIS.
There is a high risk of failure unless the
new system has been very carefully
developed and tested.
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CONVERSION
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CONVERSION
Conversion approaches Four conversion approaches are used to
change from an old to a new system:
Direct conversion Parallel conversion
Phase-in conversion
Pilot conversion
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CONVERSION
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CONVERSION
Parallel conversion Operates the old and new systems
simultaneously for a period of time.
You can process transactions with bothsystems, compare output, reconcile
differences, and make corrections to the new
AIS.
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CONVERSION
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CONVERSION
Main advantage to parallel conversion: It protects the company from errors.
Main disadvantage:
It is costly and stressful for employees to process all
transactions twice.
Because companies often experience problems
during conversion, parallel processing has
gained widespread popularity.
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CONVERSION
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CONVERSION
Conversion approaches Four conversion approaches are used to
change from an old to a new system:
Direct conversion Parallel conversion
Phase-in conversion
Pilot conversion
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CONVERSION
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CONVERSION
Conversion approaches Four conversion approaches are used to
change from an old to a new system:
Direct conversion Parallel conversion
Phase-in conversion
Pilot conversion
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CONVERSION
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CONVERSION
Pilot conversion Implements a system in just one part of the
organization, e.g., a branch office or a single store.
When problems with the system are resolved, the
new system could be implemented at the remaininglocations.
Advantages: Localizes conversion problems and allows training in a live
environment.
Disadvantages: Long conversion time.
Need for interfaces between old and new systems.
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CONVERSION
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CONVERSION
Data conversion Data conversion can be time-consuming,
tedious, and expense.
The difficulty and magnitude is easy to
underestimate. Data files may need to be modified in three
ways: Files may be moved to a different storage medium
(e.g., tape to disk).
Data content may be changed (e.g., fields addedor deleted).
A file or database format may be changed.
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CONVERSION
Steps in the data conversion process: Decide which data files need to be converted.
Check files for completeness and data inaccuracies,and remove any inconsistencies.
Do the actual data conversion.
Validate the new files to ensure data were not lostduring conversion.
If the file conversion is lengthy, update the new fileswith transactions that occurred during dataconversion.
After conversion and testing, monitor the system tomake sure it runs smoothly and accurately.
Document the conversion activities.
Systems
Analysis
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Analysis
Conceptual
Systems
Design
Physical
Design
Implementation
and
Conversion
Operation
and
Maintenance
OPERATIONS AND MAINTENANCE
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The last step in the SDLC is to operateand maintain the new system.
A post-implementation reviewshould be
conducted to ensure the new AIS meetsits planned objectives.
OPERATIONS AND MAINTENANCE
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2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 156 of 173
Factors and questions include: Goals and objectives
Does the system help the organization meet its goals,
objectives, and overall mission?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
138/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 157 of 173
Factors and questions include: Goals and objectives
Satisfaction Are users satisfied?
Do they want changes or improvements?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
139/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 158 of 173
Factors and questions include: Goals and objectives
Satisfaction
Benefits Were the expected benefits achieved?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
140/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 159 of 173
Factors and questions include: Goals and objectives
Satisfaction
Benefits
Costs Are actual costs in line with expected costs?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
141/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 160 of 173
Factors and questions include: Goals and objectives
Satisfaction
Benefits
Costs
Reliability Has the system failed, and if so, why?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
142/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 161 of 173
Factors and questions include: Goals and objectives
Satisfaction
Benefits
Costs
Reliability
Accuracy
Does the system produce accurate and complete
data?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
143/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 162 of 173
Factors and questions include: Goals and objectives
Satisfaction
Benefits
Costs
Reliability
Accuracy
Timeliness
Does the system produce timely information?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
144/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 163 of 173
Factors and questions include: Compatibility
Are hardware, software, data, and procedures
compatible with existing systems?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
145/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 164 of 173
Factors and questions include: Compatibility
Controls and security
Are there safeguards against unintentional errors,
fraud, and intrusion?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
146/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 165 of 173
Factors and questions include: Compatibility
Controls and security
Errors Are there adequate error-handling procedures?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
147/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 166 of 173
Factors and questions include: Compatibility
Controls and security
Errors
Training
Are systems personnel and users adequately
trained?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
148/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 167 of 173
Factors and questions include: Compatibility
Controls and security
Errors
Training
Communications Is the communications system adequate?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
149/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 168 of 173
Factors and questions include: Compatibility
Controls and security
Errors
Training
Communications
Organization changes
Are structural changes that resulted from the system
beneficial or harmful?
If harmful, how can they be resolved?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
150/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 169 of 173
Factors and questions include: Compatibility
Controls and security
Errors
Training
Communications
Organization changes
Documentation
Is documentation complete and accurate?
OPERATIONS AND MAINTENANCE
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7/27/2019 Romney Ab.az.Ch20
151/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 170 of 173
Any problems discovered during thereview should be brought to
managements attention, and adjustments
should be made. When the review is complete, a post -
implementation review repo rtis
prepared. User acceptance of that report is the final
activity in systems development.
OPERATIONS AND MAINTENANCE
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152/153
2008 Prentice Hall Business Publishing Accounting Information Systems, 11/e Romney/Steinbart 171 of 173
Control of the AIS is then passed to thedata processing department.
But the work is not done.
About 30% of the work takes place duringdevelopment.
The remaining 70% is spent in maintaining
the systemparticularly with respect to
software modifications and updates.
SUMMARY AND CONCLUSIONS
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153/153
Youve learned in more depth about the activitiesthat take place in the conceptual design phase ofthe systems development life cycle (SDLC).
Youve also learned about activities that takeplace in the physical systems design phase.
Youve explored what happens during thesystems implementation and conversionprocess.
Finally, youve learned about the activities in thelast phase of the systems development life