WEEK 2: SYSTEM DEVELOPMENT LIFE CYCLE AND SOFTWARE PROCESS (copy)

Systems Development Life Cycle (SDLC)

A phased approach to analysis and design that holds that systems are best developed through the use of a specific cycle of analyst and user activities.

The Heart of the Systems Development Process

1. Planning

2. Analysis

3. Design

4. Implementation

5. Maintenance

Analysis-design-code-test-loop

1. Analysis

2. Design

3. Code

4. Test

Software Process

Is the set of related activities and associated outcome that produce a software product.

4 Fundamental Process Activities

1. Software specification

2. Software development

3. Software validation

4. Software evolution

Software specifation

The functionality of the software and constraints on its operation must be defined.

Software development

The software to meet the requirement and specification must be produced.

Software validation

The software must be validated to ensure that it does what the customer wants

Software evolution

The software must evolve to meet changing customer/client needs

Software Process Models

Is a specified definition of a software process, which is presented from a particular perspective and thus only provides partial information about that process.

Software Process Models

These generic models are high-level, abstract descriptions of software processes that can be used to explain different approaches to software development.

Software Process Models

• Play a crucial role in ensuring that projects are executed smoothly in software development.

• They provide all team members with a common language and understanding, promoting effective collaboration and communication.

Types of Software Process Models

1. The Waterfall Model

2. Agile Model

3. Iterative Model

The Waterfall Model

• This is a linear, sequential approach that progresses strictly top-down. It follows a structured flow, where each phase of the development cycle must be completed before progressing to the next.

• This model is ideal for projects with well-defined and stable requirements.

Agile Model

• This emphasizes flexibility and adaptive planning. It promotes iterative development, allowing teams to deliver working software in frequent, short iterations.

• This model is well suited for projects with changing requirements and a need for 1 quick responses to customer feedback.

Iterative Model

• This model focuses on incremental development, where each iteration produces a working software component.

• This approach allows for early prototyping and testing, enabling feedback-driven improvements throughout development.

Benefits of Using Software Process Models

1. Efficiency in Software Development

2. Quality Assurance and Risk Managemen

Efficiency in Software Development

By providing a structured approach to software development. They enable teams to streamline their workflows, minimizing the risk of missed deadlines or overlapping tasks

Quality Assurance and Risk Management

Facilitate robust quality assurance and risk management practices. These models ensure that software is thoroughly tested before deployment by defining specific checkpoints and validation processes.

Factors to consider in choosing the right Software Process Models

1. Project size and complexity

2. Stability of requirements

3. Customer involvement and feedback

4. Team size and expertise

5. Schedule and time constraints

Software Quality Factors

1. Product revision

2. Product transition

3. Product operation

Product Revision Software Quality Factors

1. Maintainability

2. Flexibility

3. Testability

Product Transition Software Quality Factor

1. Portability

2. Reusability

3. Interoperability

Product Operation Software Quality Factors

1. Correctness

2. Reliability

3. Usability

4. Integrity

5. Efficiency

Correctness

This refers to the accuracy, completeness, timeliness, and availability of the software's output, as well as adherence to coding and documentation standards

Reliability

Focuses on minimizing service failures by determining the maximum allowed failure rate for the software or its functions.

Efficiency

Concerns the hardware resources required, such as processing power, storage and data communication, as well as the time between recharging portable units.

Integrity

Involves the security of the software system, ensuring that access is restricted to authorized users with appropriate permissions.

Usability

Addresses the ease with which new staff can be trained to use and operate the software system.

Maintainability

Involves the effort required to identify, fix, and verify software failures by users and maintenance personnel.

Flexibility

Focuses on the software's ability to adapt to new situations and users without requiring changes to the software itself.

Testability

Concerns the ease of testing the software, including predefined results, log files, and automatic diagnostics to ensure all system components are functioning correctly and to report any detected issues.

Portability

Ensures that the software can be adapted to different environments, such as various hardware or operating systems, allowing the same software to function in diverse situations.

Reusability

Involves designing software modules that can be reused in future.

Interoperability

Focuses on creating interfaces that allow the software to work seamlessly with other software systems or equipment firmware.