Chapter 1 lesson 3

1
Systems Analysis and Design

• Chapter 1 Lesson 3 The Systems Development Life
  Cycle (SDLC) 

2
The Systems Development Life Cycle
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• is a systematic and orderly approach to solving
  business problems, and developing and supporting
  resulting information systems.
• Traditional methodology used to develop,
  maintain, and replace information systems.
• Evolution of process that is followed in
  implementing a computer-based information system.
• It sometimes called an Applications Development
  Life Cycle

Page 1-17
The SDLC
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4
Phase1 Identifying Problems, Opportunities and
Objectives
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• This stage is critical to the success of the rest
  of the object, because no one wants to waste
  subsequent time addressing the wrong problem.
• The Analyst pinpoints problems.
• Opportunities are situations that the that the
  analyst believes can be improve upon through the
  use of computerized information systems
• The Analyst must discover what the business is
  trying to do to reach its objectives by
  addressing specific problems or opportunities.

Page5-17
The SDLC
5
Phase1 Identifying Problems, Opportunities and
Objectives
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Recognize the Problem
• What is a problem?
• When is a problem advantageous?
• Define the problem
• Is it the correct problem?
• Set System Objectives
• How will you solve the problem?
• Identify system constraints
• What are the boundaries/limitations of the
  system?

Steps
Page6-17
The SDLC
6
Phase2 Determining Information Requirements
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Formal process of using research, interview,
  questionnaires, sampling and other techniques to
  collect information about system, requirements
  and preferences.
• SA team collects information on what the system
  should do from as many sources as possible from
  users of the current system, from observing users
  and from existing reports, forms and procedures
  information gathering, data collection, data
  gathering

Page7-17
The SDLC
7
Phase3 Analyzing System Needs
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Analysis
• The study o the existing system for the purpose
  of designing a new or improved system
• Announce the systems study
• What is the reason of the study?
• What benefits will the employees and the
  organization get from the study?

Steps
Page8-17
The SDLC
8
Phase 3 Analyzing System Needs
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Cont.
• Organize the project team
• Who does that?
• Define the information needs
• - what kind of information will be needed?
• - what tools should be used to get the
  information effectively?
• Define the system performance criteria
• Prepare the design proposal

Page9-17
The SDLC
9
Phase 3 Analyzing System Needs
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Activities
• Identify and describe complete problem
  specification
• Studies and documents the current system in
  terms of its problems, requirements for the new
  system
• Prepares a list of requirements for the new
  system
• Diagram the functions of the existing system
  necessary for the development of the new system

Page10-17
The SDLC
10
Phase 4 Designing the Recommended System
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Design
• The determination of the process and data that
  are required by a new system
• Prepare the detailed systems design
• Identify alternative system configurations
• Evaluate alternative system configurations
• Select the best configuration
• Prepare the implementation proposal
• Approve or reject the proposal

Steps
Page11-17
The SDLC
11
Phase 4 Designing the Recommended System
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Design the user interface
• Design Output
• Design input
• Design system controls
• Design files and/or database
• Produce program specifications
• Produce decision trees or tables

Page12-17
The SDLC
12
Phase 5 Developing and Documenting Software
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Design compute programs using structure charts,
  Nassi-Schneiderman Charts, Data Flow Diagram and
  Pseudo code
• Walkthrough program design
• Write computer programs
• Document software with help files, procedures
  manuals, and Web sites with Frequently Asked
  Questions

Page13-17
The SDLC
13
Phase 6 Testing and Maintaining the System
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Test and debug computer programs
• Test the computer system
• Enhance system
• Maintenance
• Use the system
• Audit the system
• Conduct a post implementation review
• Maintain the system
• correct the errors
• Keep the system current
• Improve the system

Page14-17
The SDLC
14
Phase 7 Implementing and Evaluating the System
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Implementation
• The acquisition and integration of the physical
  and conceptual resources that produce a working
  system
• Plan the implementation
• Announce the implementation
• Obtain the hardware resources
• Obtain the software resources
• Prepare the database

Steps
Page15-17
The SDLC
15
Phase 7 Implementing and Evaluating the System
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Prepare the physical facilities
• Educate the participants and users
• Cut over to the new system
• Conversion Methods
• Immediate / Direct
• Outright conversion from old system to new system
• Applicable to small firms/systems
• Phased
• Parallel

Cont
Page16-17
The SDLC
16
Phase 7 Implementing and Evaluating the System
DLSU-Dasmariñas-Cavite
Systems Analysis and Design

• Phased
• The new system put into use one part at a time
• Popular to large-scale systems
• Parallel
• Old system is implemented simultaneously with the
  new one
• Greatest assurance against failure but most
  expensive

Cont
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The SDLC
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Phase 7 (Continued)

• Personnel involved
• Analyst.
• System designer.
• Programmers.
• User management.
• User operations workers.
• Systems management.

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Rapid Application Development

• Rapid Application development (RAD) is an
  object-oriented approach to systems development.

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System Maintenance

• System maintenance is
• Removing undetected errors, and
• Enhancing existing software.
• Time spent on maintenance typically ranges from
  48-60 percent of total time.

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System Enhancements

• Systems are enhanced for the following reasons
• Adding additional features to the system.
• Business and governmental requirements change
  over time.
• Technology, hardware, and software are rapidly
  changing.

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