Ch12-13 Systems Development

Systems Development

Principles of Information Systems, Seventh Edition 2

• Effective systems development requires a team effort from stakeholders, users, managers, systems development specialists, and various support personnel, and it starts with careful planning

• Identify the key participants in the systems development process and discuss their roles

• Identify important system performance requirements of transaction processing applications that run on the Internet or a corporate intranet or extranet


• Systems development often uses tools to select, implement, and monitor projects

• Discuss the key features, advantages, and disadvantages of the traditional, prototyping, rapid application development, and end-user systems development life cycles

• Identify several factors that influence the success or failure of a systems development project


• Systems development starts with investigation and analysis of existing systems

• State the purpose of systems investigation

• Discuss the importance of performance

• State the purpose of systems analysis and discuss some of the tools and techniques used in this phase of systems development


• Designing new systems 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


• 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 activities associated with this phase of systems development


• 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.

• State the importance of systems and software maintenance and discuss the activities involved

• Describe the systems review process


An Overview of Systems Development: Participants in Systems Development

• Development team

• Responsible for determining the objectives of the information system and delivering a system that meets these objectives

• Usually consists of stakeholders, users, managers, systems development specialists, and various support personnel


Figure 12.1: Systems analyst plays an important role in the development team


Initiating Systems Development

• Systems development begins when an individual or group capable of initiating organizational change perceives a need for a new or modified system

• Systems development initiatives arise from all levels of an organization

• Systems development initiatives are both planned and unplanned

• Systems development projects may be initiated for a number of reasons


Figure 12.2: Typical Reasons to Initiate a Systems Development Project


Establishing Objectives for Systems Development: Performance Objectives

• Output quality or usefulness

• Output accuracy

• Output format quality or usefulness

• Speed at which output is produced

• Scalability of the resulting system


Cost Objectives

• Development costs

• Uniqueness costs

• Fixed investments

• Ongoing operating costs


Web-Based Systems Development: The Internet, Intranets, Extranets, and

E-Commerce

• Internet technology enables companies to extend their information systems beyond their boundaries to reach their customers, suppliers, and partners

• Dynamic core business application that runs over the Web

• Must be reliable and fault tolerant

• Must integrate with existing infrastructure

• Development and maintenance must be quick and easy


Systems Development Life Cycles

• The systems development process is also called a systems development life cycle (SDLC)

• The later in the SDLC an error is detected, the more expensive it is to correct


Systems Development Life Cycles (continued)

• Common systems development life cycles:

• Traditional

• Prototyping

• Rapid application development (RAD)

• End-user development


Figure 12.6: The Traditional Systems Development Life Cycle


The Traditional Systems Development Life Cycle

• Systems investigation: problems and opportunities are identified and considered in light of the goals of the business

• Systems analysis: study of 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 solution


The Traditional Systems Development Life Cycle (continued)

• Systems implementation: the creation or acquiring of various system components detailed in the systems design, assembling them, and placing the new or modified system into operation

• Systems maintenance and review: ensures the system operates and modifies the system so that it continues to meet changing business needs


Prototyping

• An iterative approach to the systems development process

• Operational prototype: a functioning prototype that accesses real data files, edits input data, makes necessary computations and comparisons, and produces real output

• Nonoperational prototype: a mock-up, or model, that includes output and input specifications and formats


Rapid Application Development, Agile Development, Joint Application Development, and Other Systems Development Approaches

• Rapid application development (RAD): a systems development approach that employs tools, techniques, and methodologies designed to speed application development

• RAD makes extensive use of the joint application development (JAD) process for data collection and requirements analysis


The End-User Systems Development Life Cycle

• Any systems development project in which the primary effort is undertaken by a combination of business managers and users

• End-user-developed systems can be structured as complementary to, rather than in conflict with, existing and emerging information systems


Table 12.5: When to Use Outsourcing for Systems Development


Table 12.5: When to Use Outsourcing for Systems Development (continued)


Factors Affecting Systems Development Success

• Degree of change• Continuous improvement versus reengineering• Managing change

• Quality and standards

• Use of project management tools

• Use of Computer-Aided Software Engineering (CASE) tools• Automate many of the tasks required in a systems

development effort and enforce adherence to the SDLC


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?


Figure 12.12: The Systems Investigation Team


Figure 12.13: Technical, Economic, Legal, Operational, and Schedule Feasibility


The Systems Investigation Report

• Summarizes the results of systems investigation and the process of feasibility analysis

• Recommends a course of action: continue on into systems analysis, modify the project in some manner, or drop it


Systems Analysis

• Steps of a formalized analysis procedure:

• Assembling the participants for systems analysis

• Collecting appropriate data and requirements

• Analyzing the data and requirements

• Preparing a report on the existing system, new system requirements, and project priorities


The Systems Analysis Report

• The systems analysis report should cover:

• The strengths and weaknesses of the existing system from a stakeholder’s perspective

• The user/stakeholder requirements for the new system (also called the functional requirements)

• The organizational requirements for the new system

• A description of what the new information system should do to solve the problem


Systems Design

• Answers the question “How will the information system do what it must do to solve a problem?”

• Has two dimensions: logical and physical

• Logical design: description of the functional requirements of a system

• Physical design: specification of the characteristics of the system components necessary to put the logical design into action


Logical Design

• Output requirements

• Input requirements

• Process requirements

• File and database requirements


Logical Design (continued)

• Telecommunications requirements

• Procedure requirements

• Controls and security requirements

• Personnel and job requirements


Physical Design

• Hardware specifications

• Software specifications

• Database specifications


Physical Design (continued)

• Telecommunications specifications

• Personnel specifications

• Procedure and control specifications


Design of System Security and Controls

• Preventing, detecting, and correcting errors

• Disaster planning and recovery

• Disaster planning: the process of anticipating and providing for disasters

• Disaster recovery: the implementation of the disaster plan

• Hardware backup


Design of System Security and Controls (continued)

• Disaster planning and recovery (continued)

• Software and database backup

• Telecommunications backup

• Personnel backup

• Systems controls: rules and procedures to maintain data security


The Design Report

• Primary result of systems design

• Reflects the decisions made and prepares the way for systems implementation


Figure 13.11: Typical Steps in Systems Implementation


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


Systems Review

• Process of analyzing systems to make sure that they are operating as intended

• Often compares the performance and benefits of the system as it was designed with the actual performance and benefits of the system in operation

• Event-driven review: review triggered by a problem or opportunity such as an error, a corporate merger, or a new market for products

• Time-driven review: review performed after a specified amount of time


Factors to Consider During Systems Review

• Mission• Organizational goals• Hardware and software• Database• Telecommunications• Information systems

personnel• Control

• Training• Costs• Complexity• Reliability• Efficiency• Response time• Documentation


Summary

• Systems development begins when an individual or group capable of initiating organizational change perceives a need for a new or modified system

• Information systems planning is the translation of strategic and organizational goals into systems development initiatives

• Aligning organizational goals and IS goals is critical for any successful systems development effort

• Common systems development life cycles are traditional, prototyping, rapid application development (RAD), and end-user development


Summary (continued)

• Phases of the traditional systems development life cycle: systems investigation, systems analysis, systems design, systems implementation, and systems maintenance and review

• During systems investigation, problems and opportunities are identified and considered in light of the goals of the business

• Systems analysis involves the study of existing systems and work processes to identify strengths, weaknesses, and opportunities for improvement


Summary (continued)

• Computer-Aided Software Engineering (CASE) tools automate many of the tasks required in a systems development effort and enforce adherence to the SDLC

• Object-oriented systems development is an approach to systems development that combines the logic of the systems development life cycle with the power of object-oriented modeling and programming


Summary (continued)

• Systems design answers the question “How will the information system do what it must do to solve a problem?”

• Systems design has two dimensions: logical and physical

• Logical design is description of the functional requirements of a system

• Physical design is specification of the characteristics of the system components necessary to put the logical design into action


Summary (continued)

• Steps of systems implementation: hardware acquisition, software acquisition, user preparation, personnel: hiring and training, site preparation, data preparation, installation, testing, start-up, and user acceptance

• Systems operation is the use of a new or modified system

• Systems maintenance involves checking, changing, and enhancing the system to make it more useful in achieving user and organizational goals


Summary (continued)

• Systems review is the process of analyzing systems to make sure that they are operating as intended

• Event-driven review is triggered by a problem or opportunity such as an error, a corporate merger, or a new market for products

• Time-driven review is performed after a specified amount of time

Ch12-13 Systems Development

Documents

systems development

effective systems development

new systems

importance of systems

systems analyst

webbased systems development

analysis of existing

purpose of systems analysis