Chapter 13 Systems Design, Implementation, Maintenance, and Review

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Nov 8, 2013 (3 years and 9 months ago)

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Principles of Information Systems,
Sixth

Edition


Chapter 13

13
-
1






Chapter 13


Systems Design, Implementation, Maintenance, and
Review




At a Glance



Instructor’s Manual Table of Contents




Chapter Overview




Chapter Outline




Chapter
Principles and
Objectives




Teacher Notes




Quick Quizzes




Teaching Tips




Further Readings

or Resources





Discussion Questions




Projects to Assign




Key Terms








Principles of Information Systems,
Sixth

Edition


Chapter 13

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C
hapter

O
verview



The way an information system is designed, implemented, and maintained profoundly affects the daily
functioning of an organization. Like investigation and analys
is, design, implementation, maintenance, and
review strive to achieve organizational goals, such as reduced costs, increased profits, or improved
customer service. The goal is to develop a new or modified system to deliver the right information to the
righ
t person at the right time.


Chapter Outline


Lecture Topics

Page #

Systems Design

13
-
4

Systems Implementation

13
-
5

Systems Maintenance

13
-
8

Systems Review

13
-
8






Principles of Information Systems,
Sixth

Edition


Chapter 13

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C
hapter

Principles and
O
bjectives




Principles

Learning Objectives


Designing new sys
tems or modifying existing ones
should always be aimed at helping an organization
achieve its goals.






State the purpose of systems design and discuss
the differences between logical and physical
systems design.




Outline key steps taken during the design

phase.




Describe some considerations and diagrams
used during object
-
oriented design.



Define the term RFP and discuss how this
document is used to drive the acquisition of
hardware and software.




Describe the techniques used to make systems
selection eva
luations.




The primary emphasis of systems implementation is
to make sure that the right information is delivered
to the right person in the right format at the right
time.






State the purpose of systems implementation
and discuss the various activiti
es associated
with this phase of systems development.



List the advantages and disadvantages of
purchasing versus developing software.



Discuss the software development process and
some of the tools used in this process, including
object
-
oriented program d
evelopment tools.



Maintenance and review add to the useful life of a
system but can consume large amounts of resources.
These activities can benefit from the same rigorous
methods and project management techniques
applied to systems development.






Stat
e the importance of systems and software
maintenance and discuss the activities involved.



Outline key steps taken during the design phase













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Teacher Notes




Systems Design


The purpose of
Systems design
is to
answe
r

the question, "How will the i
nformation system solve a
problem?"
The primary result of the systems design phase is a technical design that details system outputs,
inputs, and user interfaces; specifies hardware, software, databases, telecommunications, personnel, and
procedures; and s
hows how these components are related. The new system should overcome

the
shortcomings of the existing one and
help the organization achieve its goals.


Systems design is generally co
mprised of two major components:

logical design and physical design.

Logi
cal design describes the functional requirements of a system. That is, it conceptualizes what the system
will do to solve the problems identified through earlier analysis. Without this step, the technical details of
the system (such as which hardware devic
es should be acquired) often obscure the best solution. The
logical design specifications that are determined and documented include the following:




Logical design
specification




Output design



Input design



Process design



Procedures design



Telecommunicati
ons design




Physical design specifies the characteristics of the system components necessary

to put the logical design
into action. In this phase, the characteristics of each of

the following components must be specified:



Physical design
specification




Hardware design



Software design



Database design



Personnel design





A number of special system characteristics should be considered during both

logical and physic
al design.
These
include sign
-
on procedures,

interactive processing, interactive dialogu
e, error prevention and
detection, and

emergency alternate procedures.









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Object Oriented Design


Logical and physical design can be accomplished using either the traditional structured

approach or the
object
-
oriented (OO) approach to systems developmen
t.

Using the OO approach,

we design key objects and
classes of objects in the new or updated system.

The sequence of events that a new or modified system
requires is often called a scenario, which can be diagrammed in a sequence diagram.



Emergency Alter
nate Procedures and Disaster Recovery


Emergency alternative procedures and disaster recovery are important aspects of systems design. Disaster
planning is the process of anticipating and providing for disasters. A disaster can be an act of nature (a
flood
, fire, or earthquake) or a human act

(terrorism, error, labor unrest, or erasure of an important file).
The primary tools used in disaster planning and recovery are hardware, software, database,
telecommunications, and personnel backup.




Systems Control
s


Security, fraud, and the invasion of privacy are also important

design considerations. Most IS
departments
establish tight systems controls to maintain data security.

Systems controls can help prevent computer
misuse, crime, and fraud by employees and o
thers.

System controls include input, output, processing,
database, telecommunications, and personnel controls.


The Importance of Vendor Support


Whether an individual is purchasing a personal computer or an experienced company is acquiring an
expensive m
ainframe computer, the system could be obtained from one or more vendors. Some of the
factors to consider in selecting a vendor are the vendor’s

reliability and financial stability, the type of
service offered after the sale, the goods and services the ven
dor offers and keeps in stock, the vendor’s
willingness

to demonstrate its products, the vendor’s ability to repair hardware, the vendor’s ability to
modify its software, the availability of vendor
-
offered training of IS
personnel and system users, and
eva
luations of the vendor by independent organizations.



Evaluating and Selecting a System Design


The final step in systems design is to evaluate the various alternatives and select the one that will offer the
best solution for organ
izational goals.
Normall
y, evaluation and selection involves both a preliminary and a
final evaluation before a design is selected.






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Sixth

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Q
uick

Q
uiz


1.

What is the purpose of systems design?

ANSWER: To answer the question, "How will an information system solve this problem?"


2.

What pr
ocedure consists of identification numbers, passwords, and other safeguards needed
for an individual to gain access to computer resources?

ANSWER: Sign
-
on procedure


3.

_____

is a simplified process used to access an appl
ication from where it left off?

ANSWE
R: Restart procedure


4.

What term is used to describe

rules and procedures that prevent problems before they occur?

ANSWER: Deterrence controls



Systems Implementation


After the information system is designed, a number of tasks must still b
e completed bef
ore the system can
be
installed and
is
ready to o
perate. This process, called systems implementation, includes the following
components:



Components of
Systems
Implementation:






Hardware acquisition



Software acquisition or development



User preparation



Hi
ring and training of personnel



Site and data preparation



Installation



Testing



Start
-
up



User
-
acceptance




To obtain the components for an information system, organizations can purchase, lease, or rent computer
hardware and other resources from an IS vendo
r.
It is also possible to purchase used computer equipment.
This option is especially attractive to firms that are experiencing an economic slowdown.


A
pplication softwa
re can be acquired in two ways:
it can be purchased from external developers or
develo
ped in
-
house. This is normally referred to as
the make
-
or
-
buy decision.

Purchasing or leasing
externally developed software has a number of advantages, including:
lower costs, less risk regarding the
features and performance of the package, and ease of ins
tallation.


User preparation is the process of readying managers, decision makers, employees, other users, and
stakeholders for the new systems. This activity is an important
,

but often ignored
,

area of systems
implementation.


Depending on the size of th
e new system, an organization may have to hire and, in some cases, train new IS
personnel. An information systems manager, systems analysts, computer programmers, data entry
operators, and similar personnel may be needed for the new system.


The location o
f the new system needs to be prepared in a process called site preparation. For a small
system, site preparation can be as simple as rearranging the furniture in an office to make room for a




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computer. With a larger system, this process is not so easy becau
se it may require special wiring and air
-
conditioning. If the organization is computerizing its work processes, all manual files must be converted to
computer files in a process called data preparation, or data conversion. All permanent data must be placed

on a permanent storage device, such as magnetic tape or disk.


Installation is the process of physically placing the computer equipment on the site and making it
operational. Although normally the manufacturer is responsible for installing computer equip
ment,
someone from the organization (usually the IS manager) should oversee the process, making sure that all
equipment specified in the contract is installed at the proper location. After the system is installed, the
manufacturer performs several tests to

ensure that the equipment is operating as it should.


Good testing procedures are essential to make sure that the new or modified information system operates as
intended. Inadequate testing can result in mistakes and problems. Several forms of testing sh
ould be used,
including testing each of the individual programs (unit testing), testing the entire system of programs
(system testing), testing the application with a large amount of data (volume testing), and testing

all related systems together (integrat
ion testing), as well as conducting any tests required by the user
(acceptance testing).


Start
-
up begins with the final tested information system. When start
-
up i
s finished, the system is fully
operational. Direct conversion (also called plunge or direct

cutover) involves stopping the old sy
stem and
starting the new one

on a given date. Direct conversion is usually the least desirable approach because of
the potential for problems and errors when the old system is shut off and the new system is turn
ed on
at the
same time
.

The phase
-
in approach is a popular technique preferred by many organizations. In this
approach, sometimes called a piecemeal approach, components of the new system are slowly phased in
while components of the old one are slowly phased out
. Pilot start
-
up involves running the new system for
one group of users rather than all users. Parallel start
-
up involves running both the old and new systems for
a period of time. The output of the new system is
compared closely with that

of the old syst
em, and any
differences are reconciled.


Most mainframe computer manufacturers use a f
ormal user acceptance document.
This is a legal document
that usually removes or reduces the information systems vendor from liability for problems that occur after
the

user acceptance document has been signed. Because this document is so important, many companies get
legal assistance before they sign the acceptance document.




Q
uick

Q
uiz



1.

What is a term used to describe a group of skilled IS professionals with the tas
k of designing
and implementing a set of programs?

ANSWER:

Chief programmer team


2.

What type of documentation is used by computer operators, or by programmers that need to
change a system?

ANSWER:

Technical


3.

What are the three structured programming const
ructs?

ANSWER: Sequence, decision, and loop


4.

What is the process of physically placing the computer equipment on the site and making it
operational?

ANSWER: Installation








Principles of Information Systems,
Sixth

Edition


Chapter 13

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Systems Maintenance


Systems maintenance involves che
cking, changing, and enha
ncing the sy
stem
in order t
o make it more
useful

in achieving user and organizational goals
.
Once a program is written, it is likely to need ongoing
maintenance and experience has shown that frequent, minor maintenance to a program, if properly done,
can p
revent major system failures later. Some of the rea
sons for program maintenance include

the
following:



Steps to
Ensure
Privacy:






Changes in business processes.



New requests from stakeholders, users, and managers.



Bugs or errors in the program.



Technica
l and hardware problems.



Corporate mergers and acquisitions.



Government regulations.



Change in operating systems or hardware platforms.





Q
uick

Q
uiz



1.

Many companies do

n
o
t announce to users that a
(n)

_____
upgrade has been made.

ANSWER: slipstream


2.

A n
ew
_____

is a significant program change that often requires changes in the
documentation of the software.

ANSWER:

release


3.

A
(n) _____

is a minor change to correct a problem or make a small enhancement.

ANSWER:

patch




Systems Review



Systems review,

the final step of systems development, is the process of analyzing systems to make sure
that
they are operating as intended. This process often compares the performance and benefits of the system
as it was designed with the actual perfor
mance and benefits

of that

in operation. Problems and opportunities
uncovered during systems review will trigger systems development and begin the process anew.


There are two types of review procedures: event driven and time driven. An event
-
driven review is
triggered by
a problem or opportunity such as an error, a corporate merger, or a new market for products. In
some cases, companies wait until a large problem or opportunity occurs before a change is made, ignoring
minor problems. In contrast, some companies use a conti
nuous improvement approach to systems
development. With this approach, an organization makes changes to a system even when small problems or
opportunities occur.


A time
-
driven review is performed after a specified amount of time. With this approach, an e
xisting system
is monitored on a schedule. If problems or opportunities are uncovered, a new systems development cycle
may be initiated.





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Q
uick

Q
uiz



1.


What type of review would be used after a system error occurred?


ANSWER: Event
-
driven
review


2.


What is the final step in systems development?


ANSWER: Systems review


3.

What type of review is conducted periodically?


ANSWER: Time
-
driven review




Teaching Tips




Invite a member of a systems development team into

the classroom to discuss a project.



Invite a programmer into the class to lead a discussion about their job. A chief programmer, who can
provide information about system conversion, is a good choice.



Demonstrate an automatic code generator. Microsoft Acc
ess can be used to illustrate the generation of
SQL if other packages are not available.



Show students an example of computer code from an actual process. Identify any business rules that
can be found in it.



Ask students to find articles on software main
tenance and review. Ask them to locate a numeric figure
that indicates the average percent of IS budgets spent on maintenance.



Conduct a systems development process as an in
-
class exercise. Develop an implementation schedule
for a class Web site. Determine

whether in
-
house development or external software packages should
be used.



Bring a software contract or acceptance test script to the class.



Ask students to search the Web for software contracts and test documents. Many exist. What are some
of their key
points?



Discuss a contract for systems acquisition. What are some key elements?



Further Readings or Resources


Readings


Ferry, D. and N. Ferry. 2000.
77 Sure
-
Fire Ways to Kill a Software Project: Destructive Tactics That
Cause Budget Overruns, Late Del
iveries, and Massive Personnel Turnover
. iUniverse.com Publishers.


Parkinson, J. 1995.
60 Minute Software : Strategies for Accelerating the Information Systems Delivery
Process (Ernst & Young Information Management Series).

John Wiley & Sons.


Pigoski, T
. 1996.
Practical Software Maintenance : Best Practices for Managing Your Software
Investment.

John Wiley & Sons.


Software Development Sites


http://www.center.org/

http://www.sdmagazine.com/





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Discussion Questions


Some interesting topics of discussion i
n this chapter include the following:





Discuss the various stages of the systems development life cycle.



Discuss the differences between a systems analyst and a system designer.


Projects to Assign


1.

Assign Review Questions: 3, 5, 8, and 17

2.

Assign Problem
Solving Exercise 2.

3.

Assign Team Activity 1 or Web Exercise 2 or Case 3.




Key Terms




Acceptance testing


conducting any test required by the user.



Cost/Benefit analysis
-

an approach that lists the costs and benefits of each proposed system.



Make
-
or
-
buy
decision
-

the decision regarding whether to obtain the necessary software from
internal or external sources.



Patch
-

a minor change to correct a problem or make a small enhancement.



Release

-

a significant program change that often requires changes in the

documentation of the
software.



Unit testing



testing of individual programs
.



User documentation

-

written description developed for individuals who use a program,
showing users, in easy
-
to
-
understand terms, how the program can and should be used
.



Version

-

a major program change, typically encompassing many new features
.



Volume testing

-

testing the application with a large amount of data
.