Embedded Systems Design and Development
Using the Waterfall Model
Embedded systems are an integral part of the technological world. From smartphones and home appliances to automotive systems and space technology, embedded systems are everywhere.
The Waterfall Model is a sequential design process often used in software development, where progress flows steadily downwards (like a waterfall) through several phases – Requirements Gathering, Design, Implementation, Verification, and Maintenance.
Each stage relies heavily on the information and results from the previous stage, which means that errors or changes can be costly if they're discovered later in the process.
As technology continues to evolve at a breathtaking pace, the complexity of embedded systems has grown exponentially, necessitating efficient models for their design and development. One such model is the Waterfall Model, a linear-sequential life cycle model widely employed in the software development process.
The waterfall model represents a cycle- specifically a series of steps appearing much like a waterfall. It is the model which is used for linear process development.
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It is a sequential design process, often used in software process development in which progress is seen as flowing steadily downwards through the phases of Conception, Initiation, Analysis, Design, Construction, Testing, Production/Implementation, and Maintenance.
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The waterfall model for software development was first used in industries like manufacturing and construction, where changing something after it's been built is very expensive or even not possible.
Because there were no methods specifically designed for creating software at the time, this model was borrowed from these industries.
The process includes the following stages: outlining the requirements, initial design, reviewing the design, detailed design, another review of the design, and finally, implementation and review.
Steps in waterfall model
The steps are:
- Specification
- Preliminary design
- Design review
- Detailed design
- Design review
- Implementation
- Review.
Requirement Gathering
This stage involves the systematic collection of all necessary information that will guide the development of the project. This could include understanding the specific features and functionality the client desires. It's also where we define the system requirement specifications, outlining what the system should accomplish.
Design
In the design phase, we create a detailed plan for how to implement the gathered requirements. We develop algorithms that will guide the coding process. Essentially, this phase determines how the system will fulfill the requirements.
Coding
Based on the design and algorithms developed in the previous stage, we now write the actual code. The code should be efficient and align with the outlined design, ensuring that the system functions as intended.
Testing
After the code has been written, we enter the testing phase. This involves rigorous checks to ensure the code performs as expected under various conditions and inputs. If any issues or 'bugs' are found, they are reported and addressed, usually by returning to the design or coding stage to make necessary corrections. This phase ensures that the final product is robust and reliable.
Maintenance
This phase requires continuous updates and improvements to keep the system functioning optimally and in line with the evolving needs and technological advancements. Here are the critical steps involved in the maintenance phase:
- This involves strategizing and executing various transition activities like the development and execution of the maintenance plan. It also includes preparing for handling potential issues that might have been identified during the development phase and ensuring robust product configuration management to accommodate any changes or updates.
- Once the system comes under the maintenance team's purview, any issues or modification requests must be thoroughly analyzed. Maintenance engineers need to confirm the issue (by reproducing it), assess its validity, investigate the cause, propose a suitable solution, and document the entire process. Before implementing any modifications, necessary approvals must be obtained.
- This step involves carrying out the approved modifications. It requires careful planning and execution to ensure that the changes don't interfere with the system's overall functionality and performance.
- After the modification has been implemented, it needs to be validated. This is usually done by confirming the changes with the individual who made the request, ensuring that the implemented modifications have effectively addressed the problem.
- While not a routine part of maintenance, there may be instances where the software needs to be ported to another platform without changing its functionality. In such cases, a special maintenance project team is often assigned to oversee the migration process.
- The final stage in the software maintenance process is software retirement. This is an infrequent event that involves decommissioning a piece of software when it's no longer needed or has been superseded by a newer version or system. While not a daily task, planning for software retirement is essential to ensure a smooth transition and to mitigate any potential impacts on the overall system.
The maintenance phase is a vital part of the Waterfall Model in embedded systems design and development. It ensures the system continues to meet its requirements while adapting to evolving needs and technologies.