Transcript Document 7481226

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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 14 Information systems development
CHAPTER 14
INFORMATION SYSTMES
DEVELOPMENT
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 14 Information systems development
Learning Objectives
 Discuss the concept of a systems development life cycle
(SDLC)
 Describe the information systems planning process
 Discuss the advantages and disadvantages of the
traditional development, prototyping, rapid application
development, object-oriented development, and end-user
development life cycles
 Identify the advantages and disadvantages of CASE tools
 Evaluate the alternatives to in-house systems development
 Discuss the key features of Internet and intranet
development
Introduction to Information Technology
Turban, Rainer and Potter
Chapter 14 Information systems development
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Chapter Overview
Information Systems
Planning
• The IS Strategic Plan
• The IS Operational
Plan
The Traditional SDLC Alternative Methods for
Systems Development
• System Investigation • Prototyping
• Systems Analysis
• Join Application Design (JAD)
• Systems Design
• Rapid Application
• Programming
Development (RAD)
• Testing
• Integrated Computer-Assisted
• Implementation
Software Engineering (ICASE)
• Operation and
Tools
Maintenance
• Object-Oriented Development
Systems Development
Outside the IS Department
• End-User development
• External Acquisition of
Software
• Outsourcing
Building Internet and
Intranet Applications
• An Internet and Intranet
Development Strategy
• Java - A Promising Tool
Introduction to Information Technology
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Case: Success in Systems Development
at Inland Steel is a Team Effort
 The Business Problem
 How to complete Inland Steel’s Order
Fulfillment System (OFS), a huge systems
development project, successfully on time and on budget
The Solution
 reviewed all requests from the business units for changes and
enhancements, and approved only a dozen, to minimize the
tendency of a project’s goals to grow beyond initial
specifications during the development process
The Results
 reduce by 50 percent the response time to customer inquiries
 upgraded and expanded some jobs from clerical to
professional functions
 integrating information in an IBM DB2 relational database
that previously had resided in isolated databases
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Introduction to Information Technology
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Chapter 14 Information systems development
Case (continued…)
What have we learned from this case??
 Information system’s timely and careful
development is a very high priority
 Many firms no longer attempt a major
systems development by themselves
 System development is a team effort that often
includes end users, top management, IS
professional, vendors, consultants, and
whatever other specialized expertise is
necessary
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Information Systems Planning
Organization
Mission
Business
Assessment
Organization
Strategic Plan
IS Planning Process
Current Information
Technology Architecture
IS Strategic Plan
New information Technology Architecture
IS Operational Plan
IS Development Projects
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IS Planning (continued …)
The IS Strategic Plan
 Objectives
 it must be aligned with the organization’s strategic plan
 it must provide for an IT architecture that enables
users, applications, and databases to be seamlessly
networked and integrated
 it must efficiently allocate IS development resources
among competing projects, so the projects can be
completed on time, within budget, and have required
the functionality
 Issues : efficiency; effectiveness; competitiveness
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IS Planning (continued …)
The IS Operational Plan
 Mission : the mission of the IS function
 IS environment : the summary of the information needs
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of the functional areas and of the organization as a whole
Objectives of the IS function : the IS function’s current
best estimate of its goals
Constraints on the IS function : technological, financial,
and personnel limitations on the IS function
Long-term systems need : a summary of the processes
needed by a company and the IS projects selected to
support them and reach organizational goals
Short-range plan : an inventory of current projects, and a
detailed plan of projects to be developed or continued
during the current year
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 14 Information systems development
The Traditional Systems
Development Life Cycle (SDLC)
 SDLC - the development method used by most
organizations today for large, complex systems
 Waterfall Approach - a sequence of steps in the SDLC
with cycles returned to previous stops
 Systems Analysts - IS professionals who specialize in
analyzing and designing information systems
 Programmers - IS professionals who modify existing
computer programs or write new computer programs to
satisfy user requirements
 Technical Specialists - experts in a certain type of
technology, such as databases or telecommunications
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SDLC (continued …)
An eight-stage systems
development life cycle
(SDLC)
(1) Systems Investigation
(2) Systems Analysis
(3) Systems Design
(4) Programming
(5) Testing
(6) Implementation
(7) Operation
(8) Maintenance
Go Back to a previous Stage or Stop
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Introduction to Information Technology
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Chapter 14 Information systems development
SDLC (continued …)
Systems Investigation (Step 1)
 Feasibility Study determines the probability of
success of proposed system’s development project
and assesses the project’s
 technical feasibility : determines if the hardware,
software, and communication components can be
developed or acquired to solve the business problem
 economic feasibility : determines if the project is an
acceptable financial risk and if the organization can
afford the expense and time needed to complete the
project
 behavioral feasibility : addresses the human issues of the
project
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Chapter 14 Information systems development
SDLC (continued …)
Systems Analysis (Step 2)
 the examination of the business problem
that the organization plans to solve with
information systems
 produces the following information
 strengths and weaknesses of the
existing system
 functions that the new systems must
have to solve the business problem
 user information requirements for the
new systems
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SDLC (continued …)
Systems Design (Step 3)
 describes how the system will accomplish the task
 technical design
 system outputs, inputs, and user interfaces
 hardware, software, databases, telecommunications,
personnel, and procedures
 how these components are integrated
 local systems design : what the system will do
 Physical systems design : how the system will
perform its functions
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SDLC (continued …)
Programming (Step 4)
 the translation of the design specifications
into computer code
 structured programming techniques :
improve the logical flow of the program by
decomposing the computer code into
modules, which are sections of code
 sequence structure
 decision structure
 loop structure
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SDLC (continued …)
Testing (Step 5)
 checks to see if the computer code will
produce the expected and desired results
under certain conditions
 syntax errors : misspelled word or a
misplaced comma
 logic errors : permit the program to run,
but result in incorrect output
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SDLC (continued …)
Implementation (Step 6)
 the process of converting from the old system to the
new system
 four major conversion strategies
 parallel conversion : the old and new systems
operate simultaneously for a period of time
 direct conversion : the old system is cut off and the
new systems is turned on at a certain point in time
 pilot conversion : introduces the new system in one
part of the organization
 phased conversion : introduces components of the
new systems in stages
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SDLC (continued …)
Operation (Step 7)
 the new systems will operate for a period
of time, until it no longer meets its
objectives
Maintenance (Step 8)
 debugging the program
 updating the system to accommodate
changes in business conditions
 add new functionality to the system
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Prototyping
Prototyping obtain only a general idea of user
requirements
 Advantages:
speeds up the development approach
gives the users the opportunity to clarify their
information requirements
useful in the development of decision support systems
and executive information systems
 Disadvantages:
 replaces the systematic analysis and design stages of
the SDLC - quality may be sacrificed
 can result in an excess of iterations
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Joint Application Design (JAD)
JAD is a group-based method for collecting user
requirements and creating staged designs
 Advantages:
saves time
greater support for, and acceptance of new systems
produces higher quality systems
easier implementation
lower training costs
 Disadvantages:
 very difficult to get all users to JASD meetings
 all the problems that may be caused by any group process
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Rapid Application Development
(RAD)
 RAD is a systems development method that can
combine JAD, prototyping, and integrated CASE
tools, to rapidly produce a high-quality system
 Advantages:
active involvement of users in the development process
speeds the development process
reduces development costs
can create applications that are easier to maintain and
modify
 Disadvantages:
 may result in systems with limited functionality and
adaptability for change
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Integrated Computer-Assisted Software
Engineering (ICASE) Tools
 ICASE Tools automate many of the tasks in the SDLC
 Upper CASE, lower CASE and integrated CASE
 Advantages:
produces systems with a longer effective operational life
speeds up the development process and result in systems that
are more flexible and adaptable to changing business conditions
results in excellent documentation
 Disadvantages:
 more expensive to build and maintain initial system
 requires more extensive and accurate definition of user needs
and requirements
 difficult to customize and may be difficult to use with existing
system
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Object-Oriented Development
 Object-Oriented Development based on a fundamentally
different view of computer systems than that found in traditional
SDLC development approaches
 Advantages:
reduces the complexity of systems development and leads to systems
that are easier and quicker to build an maintain
improves programmers’ productivity and quality
more flexible
allows systems analysts to think the real-world systems
ideal for developing Web applications
depicts the various elements of an information systems in user
standing of what the new system does and how it meets its objectives
 Disadvantages
 runs more slowly
 needs to retain the programmers
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Systems Development outside
the IS Department
End-User Development
 users will continue to do more ad hoc programming
 Types of end-user computing:
 non programming end users : enter data, use
applications
 command-level users : access data, print reports
 end-user programmers : develop applications for
personal use
 functional support personnel : develop applications
for others to use
 end-user computing support personnel : training,
hotline, help users develop applications
 programmers : develop complex applications
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Chapter 14 Information systems development
Systems Development outside
the IS Department (continues …)
End-User Development (CONT’)
 Factors that drive the trends toward increased
end-user computing and end-user development
 increasingly powerful desktop hardware
 declining hardware costs
 increase diverse software capabilities
 increasingly computer literate population
 backlog of IS projects
 development speed
 business orientation
 small applications
 control
 Apparent cost savings  User friendly software
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Introduction to Information Technology
Turban, Rainer and Potter
Chapter 14 Information systems development
Systems Development outside
the IS Department (continues …)
 Advantages of End-User Development
 gives users control over both the initial development of
an application and the ongoing maintenance
 no need to explain user requirements to IS analysts
 gives users control over the development budget
 results in the possibility of greater user acceptance
 Disadvantages of End-User Development
 needs some additional spending
 difficult for managers outside the IS area to evaluate
end-user development activities
 fail to produce adequate documentation for the systems
 security may be breached
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Systems Development outside
the IS Department (continues …)
External Acquisition of Software
 factors considered during make-or-buy
decision
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on-time
on-budget
full functionality
user acceptance
favorable costs-to-benefits ratio
low maintenance
scalability
integration with other systems
minimal negative cross-impacts
reusability
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Systems Development outside
the IS Department (continues …)
Outsourcing
 purchase of any product or service from other company
 advantages:
 Disadvantages:
economies of scale of
hardware
economies of scale of
staffing
specialization
tax benefits
 guidelines:
 limited economies of scale
 staffing
 lack of business expertise
 contract problems
 internal cost reduction
opportunities
 write short-period contracts
 subcontracting
 selective outsourcing
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Introduction to Information Technology
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Chapter 14 Information systems development
Building Internet and
Intranet Applications
An Internet and intranet
Development Strategy
 identify the objectives for
organizational Web site(s) and pages
 adequately cover infrastructure
requirements as well as security are
legal issues
 identify and prioritize potential projects
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Chapter 14 Information systems development
Internet and Intranet
JAVA - A Promising Tools
 the most important programming language for
putting extra features into Web pages
 an object-oriented language
 can be sent from a Web server over the Internet
and then run on the computer that is viewing the
Web page
 has numerous security features to prevent
downloaded programs from damaging files or
creating other problems on the receiving computer
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What’s in IT for Me?
For Accounting
 accounting functions are traditionally data-intensive
 properly developed systems are a must
For Finance
 those acquainted with systems development
methodologies are better equipped to assist in getting the
right systems developed in the right way and budget
For Marketing
 marketing functions are hotbed of systems development
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Chapter 14 Information systems development
What’s in IT for Me? (continued …)
For Production/Operations Management
 increasingly computer-controlled and
integrated with other allied systems, from
design to logistics to inventory control to
production planning
For Human Resources Management
 new systems may require terminating
employees, hiring new employees, or changing
job descriptions