SAD CH1

Information

It fuels a business and can be a critical factor in determining whether a business succeeds or fails.

Need for Systems Analysis and Design

A series of processes systematically undertaken to improve a business through the use of computerized information systems.

Consultant
Supporting expert
Agent of Change

Roles of the Systems Analyst

Problem solver
Communicator
Strong personal and professional ethics
Self-disciplined and self-motivated

Qualities of the Systems Analyst

Systems Development Life Cycle (SDLC)

A phased approach to solving business problems through a specific cycle of analyst and user activities.

Phase 1 Identifying Problems, Opportunities, and Objectives

Interview user management, summarize knowledge, estimate project scope, and document results

Phase 1 Output

A feasibility report containing problem and objective summaries used by management to decide whether to proceed.

Phase 2 Determining Human Information Requirements

Use interviews, sampling/investigation of hard data, questionnaires, observation, and prototyping. Learn the who, what, where, when, how, and why of the current (situation) system.

Phase 2 Output

Understand how users accomplish work when interacting with a computer and make the new system more useful and usable. Know the business functions and have complete information.

Phase 3 Analyzing System Needs

Create data flow, activity, or sequence diagrams; complete the data dictionary; analyze structured decisions; and prepare/present the system proposal.

Phase 3 Output

Provide a recommendation on what should be done.

Phase 4 Designing the Recommended System

Design data-entry procedures, the human-computer interface, system controls, database/files, and backup procedures.

Phase 4 Output

 The model of the actual system.

Phase 5 Developing and Documenting Software

The analyst works with programmers to develop original software and with users to create effective documentation. Programmers design, code, and remove syntactical errors. Document software with help files and Web sites.

Phase 5 Output

A computer programs and system documentation.

Phase 6 Testing and Maintaining the System

Test the information system, perform system maintenance, and maintain documentation.

Phase 6 Output

Problems found, updated programs, and documentation.

Phase 7 Implementing and Evaluating the System

Train users, plan a smooth conversion from the old system to the new system, and review/evaluate the system.

Phase 7 Output

Trained personnel and an installed system.

Human-Computer Interaction (HCI)

It focuses on how people interact with computers. A human-centered approach because it can improve system quality and quality of work life.

Maintenance

Work performed after implementation to keep a system useful and working properly. Removing software errors and enhancing existing software.

Traditional SDLC
CASE systems development life cycle
Object-oriented systems analysis and design

Approaches to Systems Development

CASE (Computer Aided Software Engineering) tools

Productivity tools explicitly created to improve systems analysts' routine work through automated support.

Increase analyst productivity, improve analyst-user communication, and integrate life cycle activities.

Reasons for using Case Tools

Agile

An approach based on values, principles, and core practices for developing systems in a flexible way.

Agile Values

Communication, Simplicity, Feedback, and Courage.

Time
Cost
Quality
Scope

Four Agile Resources

Exploration
Planning
Iterations to the first release
Productionizing
Maintenance

Five Stages of Agile Development

Object-oriented (O-O) Systems Analysis and Design

An alternative to the structured SDLC approach, intended to facilitate systems that can change rapidly in dynamic business environments.

Define the use case model; create a use case diagram and scenarios.

Create UML diagrams

Develop class diagrams

Draw statechart diagrams

Modify UML diagrams

Develop/document the system

Unified Modeling Language (UML) Phases

When to use SDLC

When documenting each step is important, management is comfortable with it, adequate time/resources exist, and communicating how the new system works is important.

When to use Agile

When applications must be developed quickly in a dynamic environment, incremental improvements satisfy the customer, a project champion exists.

When to use Object-oriented

When problems lend themselves to classes, the organization supports UML learning, systems can be added one subsystem at a time, software reuse is possible, and difficult problems can be tackled first.

Open Source Software

An alternative to traditional software development where proprietary code is not hidden from users. It is free to distribute, share, and modify.

Ad hoc
Standardized
Organized
Commercial

Four types of open source communities

General structure
Environment
Goals
Methods
User community
Licensing

Six key dimensions that differentiate open source communities

Collective Design

Through this, an IT artifact is imbued with community and organizational structures, knowledge, and practices.