system development

System Development

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เน��อหาบรรย์าย์• Overview of

Information Systems (IS)

• Information Technology Concepts

• Business and Specialized IS

• System Development

• IS in Business and Society Components of an IS

2

Overview• Participants• Information Systems

Planning Investigation and Analysis Design and Implementation Maintenance and Review

• Tools

3

Participants

Principles of Information Systems, Ninth Edition

5

An Overview of Systems Development

• Today, users of information systems are involved in their development

• This chapter will: – Help you avoid systems development

failures or projects that go over budget


6

Participants in Systems Development

• Development team– Determines objectives of the information

system– Delivers system that meets objectives

• Project – Planned collection of activities that achieves a

goal

• Project manager – Responsible for coordinating all people and

resources needed to complete a project on time


7

Participants in Systems Development (continued)

• Stakeholders– People who ultimately benefit from

project

• Users – People who will interact with the system

regularly

• Systems development specialists– Systems analysts– Programmers

Principles of Information Systems, Ninth Edition 8

Participants in Systems Development (continued)

Information Systems Planning


10

Initiating Systems Development

• Systems development initiatives– Arise from all levels of an organization– Can be planned or unplanned

• Number of reasons for initiating systems development projects–Mergers, acquisitions, federal

regulations, etc.


11

Information Systems Planning and Aligning

Corporate and IS Goals• Information systems planning– Translating strategic and organizational goals

into systems development initiatives

• Aligning organizational goals and IS goals– Critical for successful systems development

effort

• Developing a competitive advantage– Creative analysis– Critical analysis


Information Systems Planning


Aligning Corporate and IS Goals


14

Establishing Objectives for Systems Development

• Mission-critical systems– Play pivotal role in organization’s

continued operations and goal attainment

• Critical success factors (CSFs)– Factors essential to success of a

functional area of an organization


15


(continued)• Performance objectives– Output quality or usefulness– Output accuracy– Speed at which output is produced– Scalability of resulting system– Risk of the system


16


(continued)• Cost objectives– Development costs– Costs of uniqueness of system

application– Fixed investments in hardware and

related equipment– Ongoing operating costs


17

Systems Development Life Cycles

• The later in the SDLC an error is detected, the more expensive it is to correct– Previous phases must be reworked–More people are affected


Systems Development Life Cycles (continued)


19

Systems Development Life Cycles (continued)

• Common systems development life cycles:– Traditional– Prototyping– Rapid application development (RAD)– End-user development


20

The Traditional Systems Development Life Cycle

• Systems investigation– Identifies problems and opportunities and

considers them in light of business goals

• Systems analysis– Studies existing systems and work processes to

identify strengths, weaknesses, and opportunities for improvement

• Systems design– Defines how the information system will do what

it must do to obtain the problem’s solution

The Traditional Systems Development Life Cycle

(continued)• Systems implementation– Creates or acquires various system

components detailed in systems design, assembles them, and places new or modified system into operation

• Systems maintenance and review– Ensures the system operates as intended–Modifies the system so that it continues to

meet changing business needs


21


The Traditional Systems Development Life Cycle (continued)


24

Prototyping

• An iterative approach• Operational prototype– Prototype that works– Accesses real data files, edits input data,

makes necessary computations and comparisons, and produces real output

• Nonoperational prototype– A mock-up, or model– Includes output and input specifications and

formats


Prototyping (continued)


28

Rapid Application Development, Agile Development, Joint

Application Development, and Other Systems

Development Approaches• Rapid application development (RAD)– Employs tools, techniques, and

methodologies designed to speed application development

–Makes extensive use of the joint application development (JAD)

• Other approaches to rapid development– Agile development– Extreme programming (XP)


Rapid Application Development, Agile Development, Joint Application

Development, and Other Systems Development Approaches (continued)


30

The End-User Systems Development

• End-user systems development– Systems development project in which

business managers and users assume the primary effort

– Disadvantages• Some end users do not have the training to

effectively develop and test a system


31

Outsourcing and On-Demand Computing

• Reduces costs• Obtains state-of-the-art technology• Eliminates staffing and personnel

problems• Increases technological flexibility


Outsourcing and On-Demand Computing (continued)


33

Factors Affecting Systems Development Success

• Successful systems development:– Delivers a system that meets user and

organizational needs on time and within budget

• Critical for most systems development projects:– Getting users and stakeholders involved


34

Degree of Change

• Continuous improvement projects– High degree of success– Relatively modest benefits

• Managing change– Ability to recognize and deal with

existing or potential problems


Degree of Change (continued)


36

Quality and Standards

• Quality of project planning– Bigger the project, the more likely that

poor planning will lead to significant problems

• Capability Maturity Model (CMM)– One way to measure organizational

experience


Quality and Standards (continued)


38

Use of Project Management Tools

• Project schedule– Detailed description of what is to be done

• Project milestone– Critical date for completion of a major part of

the project• Project deadline– Date that the entire project is to be

completed and operational• Critical path– Activities that, if delayed, would delay the

entire project


39

Use of Project Management Tools (continued)

• Program Evaluation and Review Technique (PERT)– Creates three time estimates for an

activity• Shortest possible time• Most likely time• Longest possible time

• Gantt chart– Graphical tool used for planning,

monitoring, and coordinating projects


40

Use of Computer-Aided Software Engineering

(CASE) Tools• CASE tools – Automate many tasks required in a

systems development effort – Encourage adherence to SDLC

• Companies that produce CASE tools: – Accenture, Microsoft, and Oracle


Use of Computer-Aided Software Engineering (CASE) Tools (continued)


42

Object-Oriented Systems Development

• Combines logic of systems development life cycle with power of object-oriented modeling and programming

• OOSD tasks:– Identify potential problems and

opportunities that would be appropriate for OO approach

– Define user requirements


43

Object-Oriented Systems Development (continued)

• OOSD tasks (continued):– Design system– Program or modify modules– User evaluation– Periodic review and modification


44

Systems Investigation

• What primary problems might a new or enhanced system solve?

• What opportunities might a new or enhanced system provide?

• What new hardware, software, databases, telecommunications, personnel, or procedures will improve an existing system or are required in a new system?

• What are the potential costs (variable and fixed)?

• What are the associated risks?


45

Initiating Systems Investigation

• Systems request form– Submitted by someone who wants IS

department to initiate systems investigation

– Information included• Problems in or opportunities for system• Objectives of systems investigation• Overview of proposed system• Expected costs and benefits of proposed

system


46

Participants in Systems Investigation

• Members of development team change from phase to phase

• Keys to successful investigation teams:– Cooperation and collaboration


Participants in Systems Investigation (continued)


48

Feasibility Analysis

• Technical feasibility• Economic feasibility• Net present value• Legal feasibility• Operational feasibility• Schedule feasibility


Feasibility Analysis (continued)


50

Object-Oriented Systems Investigation

• Object-oriented approach – Can be used during all phases of

systems development

• Use case diagram– Part of the Unified Modeling Language

(UML) that is used in object-oriented systems Development


Object-Oriented Systems Investigation (continued)


52

The Systems Investigation Report

• Summarizes results of systems investigation

• Summarizes the process of feasibility analysis

• Recommends a course of action– Continue on into systems analysis–Modify the project in some manner– Drop the project

• Reviewed by steering committee


The Systems Investigation Report (continued)


54

Systems Analysis

• Overall emphasis of analysis:– Gathering data on existing system– Determining requirements for new

system– Considering alternatives– Investigating feasibility of solutions

• Primary outcome of systems analysis:– Prioritized list of systems requirements


55

General Considerations

• Steps of a formalized analysis procedure:– Assembling participants for systems

analysis– Collecting data and requirements– Analyzing data and requirements– Preparing a report on existing system,

new system requirements, and project priorities


56

Participants in Systems Analysis

• Includes members of the original investigation team

• Systems analysis team develops:– List of objectives and activities– Deadlines– Statement of resources required–Major milestones


57

Data Collection

• Identifying sources of data– Internal and external sources

• Collecting data– Interviews– Direct observation– Questionnaires


Identifying Sources of Data


Collecting Data


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Data Analysis

• Data modeling• Activity modeling• Application flowcharts• Grid charts• CASE tools


Data Analysis (continued)


62

Requirements Analysis

• Determination of user, stakeholder, and organizational needs

• Techniques:– Asking directly– Critical success factors (CSFs)– IS plan– Screen and report layout– Requirements analysis tools


Requirements Analysis (continued)


64

Object-Oriented Systems Analysis

• Identify problems or potential opportunities

• Identify key participants and collect data

• With the OO approach a class is used to describe different types of objects


Object-Oriented Systems Analysis (continued)


66

The Systems Analysis Report

• Elements:– Strengths and weaknesses of existing

system from a stakeholder’s perspective– User/stakeholder requirements for new

system – Organizational requirements for new

system– Description of what new information

system should do to solve the problem


The Systems Analysis Report (continued)


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Systems Design

• Answers the question:– How will the information system solve a

problem?

• Results in a technical design that:– Details system outputs, inputs, and user

interfaces– Specifies hardware, software, databases,

telecommunications, personnel, and procedures

– Shows how these components are related


69

Logical and Physical Design

• Logical design– Describes functional requirements of a

system

• Physical design– Specifies the characteristics of the

system components necessary to put the logical design into action


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Object-Oriented Design

• Using the OO approach:– You can design key objects and classes

of objects in the new or updated system– Process includes considering the problem

domain, the operating environment, and the user interface

• During design phase consider the sequence of events that must happen for the system to function correctly


Object-Oriented Design (continued)


72

Interface Design and Controls

• System characteristics: – Sign-on procedure– Interactive processing– Help facility– Lookup tables– Restart procedure


Interface Design and Controls (continued)


75

Design of System Security and Controls

• Preventing, detecting, and correcting errors

• Disaster planning and recovery– Disaster planning– Disaster recovery

• Systems controls– Closed shops– Open shops– Deterrence controls


76

Environmental Design Considerations

• Environmental design– Also called green design– Involves systems development efforts

that slash power consumption, require less physical space, and result in systems that can be disposed in a way that doesn’t negatively affect the environment


77

Generating Systems Design Alternatives

• Request for proposal (RFP)– Document that specifies required resources

such as hardware and software in detail

• Financial options:– Purchase, lease, or rent

• Evaluating and selecting a systems design– Preliminary evaluation– Final evaluation


Generating Systems Design Alternatives (continued)


79

Evaluation Techniques

• Group consensus• Cost/benefit analysis• Benchmark tests• Point evaluation


Evaluation Techniques (continued)


82

Freezing Design Specifications

• User agrees in writing that the design is acceptable

• Other organizations:– Allow or even encourage design

changes


Freezing Design Specifications (continued)


84

The Contract

• Vendors provide standard contracts to protect themselves

• Typically, the request for proposal becomes part of the contract


85

The Design Report

• Primary result of systems design• Reflects decisions made and

prepares the way for systems implementation


The Design Report (continued)


87

Systems Implementation

• Includes:– Hardware acquisition– Programming and software acquisition

or development– User preparation– Hiring and training of personnel– Site and data preparation– Installation, testing, start-up, and user

acceptance


88

Acquiring Software: Make or Buy?

• Make-or-buy decision–Whether to obtain software from external or

internal sources• Externally acquired software and

Software as a Service (SaaS)– Commercial off-the-shelf (COTS)

development process• In-house developed software– CASE and object-oriented approaches– Cross-platform development – Integrated development environment


89

Acquiring Database and Telecommunications

Systems• Databases – A blend of hardware and software

• Virtual databases and database as a service (DaaS) – Popular ways to acquire database

capabilities


90

User Preparation

• Readying managers, decision makers, employees, other users, and stakeholders for new systems

• Important, but often ignored area of systems implementation


91

IS Personnel: Hiring and Training

• Eventual success of any system depends on how it is used by the IS personnel within the organization

• Training programs should be conducted for the IS personnel who will be using the computer system–More detailed than user training in the

technical aspects of the systems


92

Site Preparation

• Preparation of the location of a new system

• Larger systems may require special equipment

• Developing IS sites that are energy efficient is important


93

Data Preparation

• Also called data conversion• Ensuring all files and databases are

ready to be used with new computer software and systems


94

Installation

• Process of physically placing computer equipment on the site and making it operational

• Normally, manufacturer is responsible for installing computer equipment

• Someone from the organization (usually IS manager) should oversee the process

Testing

• Unit testing• System testing• Volume testing • Integration testing • Acceptance testing• Alpha testing• Beta testing


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Start-Up

• Process of making the final tested information system fully operational

• Approaches– Direct conversion (plunge, direct

cutover) – Phase-in approach (piecemeal)– Pilot start-up– Parallel start-up


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User Acceptance

• Formal agreement signed by user that states that a phase of installation or the complete system is approved

• Legal document that removes or reduces IS vendor’s liability


98

Systems Operation and Maintenance

• Systems operation– Use of a new or modified system

• Systems maintenance– Checking, changing, and enhancing the

system to make it more useful in achieving user and organizational goals


99

Reasons for Maintenance

• Changes in business processes• New requests from stakeholders,

users, and managers• Bugs or errors in program• Technical and hardware problems• Corporate mergers and acquisitions• Government regulations


100

Types of Maintenance

• Slipstream upgrade– Usually requires recompiling all the code

• Patch–Minor change to correct a problem

• Release– Significant program change

• Version–Major program change


101

The Request for Maintenance Form

• Form authorizing modification of programs• Usually signed by a business manager• IS group:– Reviews form– Identifies programs to be changed– Determines programmer to be assigned to

task– Estimates expected completion date– Develops a technical description of change


102

Performing Maintenance

• Maintenance team– Responsible for modifying, fixing, and

updating existing software

• Maintenance function– Becoming more automated


103

The Relationship Between Maintenance and Design

• Programs are expensive to develop, but they are even more expensive to maintain

• Determining factor in decision to replace a system – The point at which it is costing more to

fix than to replace


The Relationship Between Maintenance and Design (continued)


105

Systems Review

• Final step of systems development• Analyzes systems to make sure that

they are operating as intended


106

Types of Review Procedures

• Event-driven review– Triggered by a problem or opportunity

• Time-driven review – Performed after a specified amount of

time


Types of Review Procedures (continued)


108

System Performance Measurement

• Monitoring the system– Number of errors encountered– Amount of memory required– Amount of processing or CPU time needed– Other problems

• System performance products– Software that measures all components of

the computer-based information system

Summary

• Systems development team – Stakeholders, users, managers, systems

development specialists, and various support personnel

• Five phases of the traditional SDLC:– Investigation, analysis, design, implementation,

and maintenance and review

• Advantages of the traditional SDLC:– Provides for maximum management control– Creates considerable system documentation– Produces many intermediate products for review


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Summary (continued)

• Rapid application development (RAD)– Reduces paper-based documentation– Automates program source code generation– Facilitates user participation in development

activities

• Factors that affect systems development success:– Degree of change introduced by the project– Continuous improvement and reengineering– Use of quality programs and standards


111

Summary (continued)

• Participants in systems investigation:– Stakeholders, users, managers, employees,

analysts, and programmers

• Data collection methods: – Observation, interviews, questionnaires,

and statistical sampling

• Requirements analysis – Determines the needs of users,

stakeholders, and the organization in general


112

Summary

• Purpose of systems design:– To prepare detailed design needs for a

new system

• Logical and physical design – Can be accomplished using the

traditional systems development life cycle or the object oriented approach

• Disaster recovery – Important aspect of systems design


113

Summary (continued)

• Purpose of systems implementation:– To install the system and make everything,

including users, ready for its operation

• Software can be purchased from vendors or developed in-house

• Cross-platform development and integrated development environments (IDEs) –Make software development easier and more

thorough


114

Summary (continued)

• Systems operation– Use of a new or modified system

• Maintenance – Can be as simple as a program patch to the

more complex upgrading of software with a new release from a vendor

• Systems review – Process of analyzing and monitoring

systems to make sure that they are operating as intended

system development

Documents