The document outlines the stages in the Systems Development Life Cycle (SDLC), including system investigation, analysis, design, implementation, maintenance and evaluation. It describes the key activities in each phase such as conducting feasibility studies, gathering functional requirements, designing the user interface and data structures, testing the system, and ongoing maintenance. Alternative approaches like prototyping are also covered, which allow for rapid development and user feedback early in the process.
2. STAGES/PHASES IN SDLC
SYSTEMS INVESTIGATION – PHASE 1
- Include preliminary study of proposed IS solutions to meet a
company’s e-business priorities & opportunities.
- Investigation stage:
a. determine how to address e-business opportunities.
b. conducting feasibility study.
c. develop project management plan & obtain
management approval.
3. SYSTEM INVESTIGATION : PHASE 1
• FEASIBILITY STUDY
1. Organizational feasibility
Focuses on how well a proposed system supports the e-
business priorities of the organization.
3. Economic feasibility
Focuses on whether expected cost savings, increased revenue,
increased profits, and reductions in required investment, will
exceed the costs of developing and operating a proposed
system.
4. SYSTEM INVESTIGATION : PHASE 1
3. Technical feasibility
Focus on the reliabilities/capabilities of the hardware and software to
meet the needs of the proposed system.
4. Operational feasibility
Focus on the willingness and ability of the management, employees,
customers, suppliers, and others to operate, use, and support the
proposed system.
5. Schedule feasibility
Focus on the solution be designed & implemented within an acceptable
time period.
5. SYSTEM ANALYSIS : PHASE 2
- Systems analysis is an in-depth study of end user information needs, which
produces functional requirements that are used as the basis for the design
of a new information system.
- Types of analysis:
1. Organizational Analysis
involves evaluating the organizational and environmental systems
and subsystems involved in any situation.
2. Analysis of the Present Systems
involves analyzing activities, resources
(hardware/software/people), and the products.
6. SYSTEM ANALYSIS : PHASE 2
1. Functional Requirement Analysis
Determine the information processing capabilities required for each
system activity (input, processing, output, storage, and control) to meet
the information needs.
7. SYSTEM DESIGN: PHASE 3
1. USER INTERFACE DESIGN
Focuses on supporting the interactions between end users
and their computer-based applications – EG: display
screens, interactive user/computer dialogues, audio
responses, forms, documents, and reports.
2. DATA DESIGN
- Physical View – the design shows how the database is
arranged, stored and accessed on the storage devices of a
computer system.
- Logical View – conceptual design within an abstract model.
Data elements and relationship are used in the model.
3. PROCESS DESIGN
8. SYSTEM IMPLEMENTATION: PHASE 4
The activity includes:
• Acquisition of hardware, software and services.
• Software development or modification.
• Testing of programs, procedures, and hardware.
• System documentation.
• Conversion (parallel, pilot, phased, plunge).
• End User training.
9. SYSTEM IMPLEMENTATION: PHASE 4
CONVERSION METHODS
• Parallel Conversion: - Both the old and the new system are operated until the
project development team and end user management agrees to switch
completely over to the new system.
• Phased Conversion: - Only parts of a new application or only a few
departments, branch offices, or plant locations at a time are converted. A
phased conversion allows a gradual implementation process to take place within
an organization.
• Pilot Conversion: - Where one department or other work site serves as a test
site. A new system can be tried out at this site until developers feel it can be
implemented throughout the organization.
• Plunge/Direct Cutover: - Use the system immediately and totally abandons the
old system.
11. SYSTEM MAINTENANCE / EVALUATION: PHASE 5
System Maintenance
System maintenance is the monitoring, evaluating, and modifying of
operational e-business systems to make desirable or necessary
improvements.
System Evaluation
Evaluate or judge the performance of a system over a longer time period
than that just after immediate installation.
12. SYSTEM MAINTENANCE / EVALUATION: PHASE 5
FOUR (4) PROBLEM AREAS CONTRIBUTE TO SYSTEM FAILURE
3. DESIGN
- System fail to capture essentials business requirements.
- Poor format of the system – eg: represent wrong piece of data.
- poor user interface – not user friendly. Hard to use by the user.
7. COST
- Cost to implement may be over budget.
- System project may be too costly to complete.
13. SYSTEM MAINTENANCE / EVALUATION: PHASE 5
FOUR (4) PROBLEM AREAS CONTRIBUTE TO SYSTEM FAILURE
3. Data
- Data inaccurate or inconsistent and not properly organised.
- Information in certain fields may be erroneous or ambiguous.
- Data incomplete – information may be inaccessible.
4. Operation
- System does not run well.
- Information is not available in a timely & efficient manner because computer
breakdown.
- Response time may too long.
14. ALTERNATIVE TO THE SDLC
PROTOTYPING
Prototyping is the rapid development and testing of working models, or
prototypes, of new applications in an interactive, iterative process
involving both IS specialists and business professionals.
Tools for prototyping
• Screen generators (screen painters)
• Graphics
• Report generators (report writers)
15. ALTERNATIVE TO THE SDLC
Categories of Prototypes
2. Non-working prototypes
3. Partially working prototypes.
4. Pilot prototypes
5. Staged prototypes
16. Four Steps in the Prototyping Process
• Identify the user’s basic requirements – the system designer works
with the user to capture the user’s basic information needs.
• Develop an initial prototype – the system designer creates a working
prototype quickly, using tools for rapidly generating software.
• Use the prototype – the user is encouraged, to work with the system
to determine how well the prototype meets the requirement and
make suggestions for improving the prototype.
• Revise and enhance the prototype – System builder notes all changes
the user requests and refines the prototype accordingly.
17. Advantages of Using Prototyping
• Prototyping makes the development process
faster and easier for IS specialists and business
professionals.
• Prototyping involve end-user development
throughout the systems development life
cycle.