Unit 1: System Design and Development Data UNIT 3

What is a System? System Design and Development Data refers to the UNIT :2
A system is a collection of interrelated components or documentation and information created during the design and WHAT is SDLC?
elements that work together to achieve a specific goal or development phases of a system or product. This data is A software life cycle model (also termed process model) is a
purpose. Systems can be found in various domains, including essential for ensuring that the system meets the required pictorial and diagrammatic representation of the software life
technology, business, biology, and more. Systems are often specifications and functions as intended. It includes: cycle. A life cycle model represents all the methods required
categorized by their complexity, structure, and purpose. In  Design Specifications: Detailed descriptions of the system's to make a software product transit through its life cycle
computing, a system can refer to both hardware and functionality, features, and performance criteria. stages. It also captures the structure in which these methods
software components that interact to process data and  Development Plans: Documents outlining the steps, are to be undertaken. In other words, a life cycle model maps
produce meaningful outputs. A system is a set of elements or resources, and timelines for system development. the various activities performed on a software product from
components that are organized and interact with one  Prototype and Test Data: Information collected during its inception to retirement. Different life cycle models may
another to achieve a specific purpose or function. It includes testing phases to verify system performance. plan the necessary development activities to phases in
inputs, processes, and outputs that work together within a  Design Review Records: Minutes and reports from design different ways. Thus, no element which life cycle model is
defined boundary. review meetings. followed, the essential activities are contained in all life cycle
Key Elements of a System:  Change Management Records: Documentation of any models though the action may be carried out in distinct orders
 Inputs: Resources or data provided to the system. changes made during the development process and the in different life cycle models. During any life cycle stage, more
 Processes: Operations performed within the system to rationale behind them. than one activity may also be carried out.
transform inputs. Importance: Stage1: Planning and requirement analysis .Requirement
 Outputs: The result or outcome produced by the system.  Ensures traceability and accountability during system Analysis is the most important and necessary stage in SDLC.
 Feedback: Information that helps improve the system’s development. The senior members of the team perform it with inputs from
performance by adjusting inputs or processes.  Helps in identifying and addressing issues early in the all the stakeholders and domain experts or SMEs in the
process. industry.
Learning to Recognize Types of Systems  Provides a clear record for future maintenance and Stage2: Defining Requirements Once the requirement analysis
Systems can be classified into different types based on their upgrades. is done, the next stage is to certainly represent and document
characteristics and functionality. Recognizing the type of the software requirements and get them accepted from the
Data Accession List (DAL): project stakeholders.
system helps in better understanding its operation and
The Data Accession List (DAL) is a structured list that Stage3: Designing the Software The next phase is about to
management.
catalogues all the data and documents generated during a bring down all the knowledge of requirements, analysis, and
 Natural Systems: Found in nature and occur without
project or system lifecycle. It provides a comprehensive record design of the software project. This phase is the product of the
human intervention (e.g., ecosystems, weather systems).
of: last two, like inputs from the customer and requirement
 Artificial Systems: Man-made systems designed to fulfill
 Data Ownership: Who created the data and who is gathering.
specific purposes (e.g., computer systems, economic
responsible for maintaining it. Stage4: Developing the project In this phase of SDLC, the
systems).
 Data Format: The format in which the data is stored (e.g., actual development begins, and the programming is built. The
PDF, Excel, Word). implementation of design begins concerning writing code.
2. Open vs. Closed Systems:
 Access Rights: Who has permission to view, edit, or delete Developers have to follow the coding guidelines described by
 Open Systems: Interact with their environment by
the data. their management and programming tools like compilers,
exchanging inputs and outputs (e.g., a company receiving
Data Criteria List (DCL): interpreters, debuggers, etc. are used to develop and
customer feedback).
The Data Criteria List (DCL) outlines the criteria for data implement the code.
 Closed Systems: Do not interact with their environment;
collection, storage, and usage within a system. It ensures that Stage5: Testing After the code is generated, it is tested against
they are self-contained (e.g., a chemical reaction in a
data meets specific quality standards, including: the requirements to make sure that the products are solving
sealed container).
 Accuracy: Ensuring data is correct and free of errors. the needs addressed and gathered during the requirements
 Completeness: Ensuring all necessary data is collected and stage.
Analytical Representation of a System
stored. Stage6: Deployment Once the software is certified, and no
Analyzing a system involves representing it in a way that
 Consistency: Ensuring data is presented in a uniform bugs or errors are stated, then it is deployed. Then based on
helps stakeholders understand its components, structure, and
manner. the assessment, the software may be released as it is or with
behavior. Analytical representation is crucial in system design,
Purpose: suggested enhancement in the object segment.
development, and troubleshooting.
Common Methods of Analytical Representation: Documentation Levels of Formality Stage7: Maintenance Once when the client starts using the
 Flowcharts: A visual representation of a system’s Documentation levels of formality refer to the degree of rigor developed systems, then the real issues come up and
processes and workflows. and standardization applied to system documentation. There requirements to be solved from time to time. This procedure
are generally three levels of formality: where the care is taken for the developed product is known as
 Block Diagrams: Simplified diagrams that show the
1. High Formality: maintenance.
components of a system and their interactions.
 Mathematical Models: Equations and formulas used to  Involves detailed and comprehensive documentation.
 Follows strict regulatory and compliance requirements. Waterfall Model
represent a system’s behavior and predict outcomes.
 Common in industries like aerospace, healthcare, and The Waterfall Model is one of the earliest and most traditional
 Use Case Diagrams: Illustrations of how users interact
defense. approaches to the Software Development Life Cycle (SDLC). It
with a system to achieve specific goals.
2. Medium Formality: follows a linear and sequential flow where each phase must be
Benefits of Analytical Representation:
 Involves structured documentation with moderate levels of completed before moving to the next. The process is
 Helps identify system components and their interactions.
detail. structured in distinct stages, much like a waterfall flowing
 Facilitates problem-solving and system improvement. down, hence the name. Here's a breakdown of the Waterfall
 Provides a clear understanding of system workflows.  Balances thoroughness and efficiency.
model:
 Common in industries like manufacturing and software
Key Features of the Waterfall Model:
System Stakeholders: User and End User Roles development.
3. Low Formality:  Linear Process: The process flows in one direction, from
Stakeholders are individuals or groups who have an interest in one phase to the next, without going back. Once a phase
a system and its development. They can influence or be  Involves minimal documentation, focusing on essential
is completed, you cannot go back to it.
affected by the system's performance. information.
 Well-Defined Phases: The phases of development are
Types of Stakeholders:  Prioritizes speed and flexibility.
clearly defined, and each phase has specific deliverables.
 User: Someone who interacts with the system to achieve  Common in startups and agile development environments.
 Documentation Driven: Emphasis is placed on
their tasks. Importance:
documentation. Every phase produces comprehensive
 End User: The primary person for whom the system is  Ensures that documentation meets the needs of the
documents before moving to the next phase.
designed. They experience the final output of the system. project and stakeholders.
Characteristics:
 Other Stakeholders: These may include project managers,  Helps in maintaining compliance with industry standards
 Rigid Structure: Since it is a linear model, once a phase is
developers, clients, and regulatory bodies.  Balances the need for thorough documentation with the
completed, it is difficult to go back and make changes.
Example of Stakeholders in a Library Management System: practicality of project timelines.
 Clear Documentation: Each phase produces detailed
 User: Library staff managing books. System Documentation Issues documentation, which is helpful for large teams and long-
 End User: Library members borrowing books. System documentation issues refer to the challenges and term projects.
 Other Stakeholders: IT staff, system developers, and local problems that can arise in creating, maintaining, and  Suitability for Small Projects: The Waterfall model works
authorities. managing documentation for systems. Common issues best for small projects with well-defined requirements
Importance of Stakeholders in System Development: include: that are unlikely to change during development.
•Identifying stakeholders helps in understanding their needs 1. Incompleteness: Missing critical information can lead to Pros of the Waterfall Model:
and expectations. misunderstandings and errors.  Simple and Easy to Understand: Its sequential nature
•Ensures the system meets user requirements and improves 2. Inconsistency: Inconsistent formatting, terminology, and makes it easy to understand and manage.
user satisfaction. structure can reduce the usability of documentation.  Clear Documentation: Comprehensive documentation
System Attributes, Properties, and Characteristics 3. Outdated Information: Failure to update documentation helps in better project management and troubleshooting.
Understanding the attributes, properties, and characteristics as the system evolves can lead to incorrect or irrelevant  Structured Approach: Clear milestones make progress
of a system is essential for evaluating its performance and information. easy to track.
efficiency. 4. Lack of Accessibility: If documentation is not easily
Cons of the Waterfall Model:
Characteristics of a System: accessible, it can hinder system maintenance and
 Inflexible: Once a phase is completed, it is difficult to go
 Boundary: Defines the limits of the system. troubleshooting.
back and make changes, making it unsuitable for projects
 Environment: External factors that influence the system. 5. Poor Quality Control: Lack of proper review and validation
where requirements are expected to change.
 Structure: The arrangement of components within the processes can result in low-quality documentation.
 Late Testing: Testing only happens after the coding phase,
system. Solutions to Documentation
so bugs are found late in the development process, which
 Purpose: The specific goal or function the system aims to could be costly to fix.
achieve.
 Not Ideal for Complex Projects: For complex and large-
scale projects, where requirements can evolve, the
Waterfall model may lead to inefficiencies.

 Attributes of a System: UNIT :1 Unit 2 What is the Spiral Model? UNIT 2
 Functionality: The core tasks that the system performs. Incremental Model The Spiral Model is a Software Development Life Cycle (SDLC)
 Usability: The ease with which users can interact with the Incremental Model is a process of software development model that provides a systematic and iterative approach to
system. where requirements divided into multiple standalone modules software development. In its diagrammatic representation,
 Efficiency: How well the system utilizes resources to of the software development cycle. In this model, each looks like a spiral with many loops. The exact number of loops
achieve its goals.
module goes through the requirements, design, of the spiral is unknown and can vary from project to project.
 Reliability: The consistency and dependability of the
implementation and testing phases. Every subsequent release Each loop of the spiral is called a phase of the software
system’s performance.
 Scalability: The system’s ability to handle increased of the module adds function to the previous release. The development process.
workload or expansion. process continues until the complete system achieved.
Properties of a System: Objectives determination and Identify and resolve Risks:
 Modularity: The degree to which a system's components identify alternative solutions:
can be separated and recombined.
 Connectivity: How well the components of a system are
linked.
Develop the next version
 Interdependence: The reliance of components on each
other to function properly. Review and plan of the Product:
System/Product Life Cycle Concepts for the next Phase
The System Life Cycle refers to the stages a system goes
through from its inception to its retirement. These stages Phase of spiral model
ensure that the system meets user requirements and 1) Objectives determination and identify alternative solutions:
remains functional over time.
Requirements are gathered from the customers and the
Phases of the System Life Cycle: The various phases of incremental model are as follows:
 Conceptualization: Identifying the need for a system. objectives are identified, elaborated, and analyzed at the start
1. Requirement analysis: of every phase. Then alternative solutions possible for the
 Development: Designing and building the system.
2. Design & Development:
 Implementation: Deploying the system for use. phase are proposed in this quadrant.
 Operation and Maintenance: Ensuring the system 3. Testing: 2) Identify and resolve Risks: During the second quadrant, all
continues to function as intended. 4. Implementation: the possible solutions are evaluated to select the best possible
 Retirement: Phasing out the system when it is no longer When we use the Incremental Model? solution. Then the risks associated with that solution are
needed.  When the requirements are superior. identified and the risks are resolved using the best possible
Understanding the User’s Problem, Opportunity, and  A project has a lengthy development schedule. strategy. At the end of this quadrant, the Prototype is built for
Solution Spaces
 When Software team are not very well skilled or trained. the best possible solution.
A critical part of system development is understanding the
user’s needs and challenges. This involves identifying  When the customer demands a quick release of the 3) Develop the next version of the Product: During the third
problems, exploring opportunities, and providing product. quadrant, the identified features are developed and verified
appropriate solutions.  You can develop prioritized requirements first. through testing. At the end of the third quadrant, the next
 Problem Space: The issues and challenges that users face Advantage of Incremental Model version of the software is available.
in their current processes.  Errors are easy to be recognized. 4) Review and plan for the next Phase: In the fourth quadrant,
 Opportunity Space: The potential improvements or
 Easier to test and debug the Customers evaluate the so-far developed version of the
innovations that a system can offer to address user
needs.  More flexible. software. In the end, planning for the next phase is started.
 Solution Space: The specific system features and  Simple to manage risk because it handled during its Advantages of the Spiral Model
functions that address user needs and solve problems. iteration.  Risk Handling:
Example: For an online shopping system:  The Client gets important functionality early.  Good for large projects:
 Problem Space: Difficulty in managing inventory and Disadvantage of Incremental Model  Flexibility in Requirements: Iterative and Incremental
processing orders.
 Need for good planning Approach:
 Opportunity Space: Automating order management and
 Total Cost is high. Disadvantage of Spiral Model
providing a user-friendly interface.
 Solution Space: Developing an e-commerce platform with  Well defined module interfaces are needed.  Complex
inventory tracking and secure payment processing. What is Agile Model?  Expensive.
Commercial/Consumer Product Versus Contract System The Agile Model was primarily designed to help a project  Too much dependability on Risk Analysis:.
Development adapt quickly to change requests. So, the main aim of the Agile  Difficulty in time management
Understanding the difference between commercial model is to facilitate quick project completion. To accomplish  Time-Consuming
consumer products and contract system development is this task, agility is required. Agility is achieved by fitting the  A spiral approach is utilized when frequent
essential for system designers and developers. process to the project and removing activities that may not be releases are necessary.
Commercial/Consumer Products: These systems are
essential for a specific project. Also, anything that is a waste of Where to use the Spiral Model
developed for mass-market consumers. They are designed to
meet general needs and are available to the public. time and effort is avoided. The Agile Model refers to a group  When it is appropriate to create a prototype
Examples: Mobile ,apps ,Laptops ,Household appliances of development processes. These processes share some basic  When evaluating risks and costs is crucial
Contract System Development: These systems are custom- characteristics but do have certain subtle differences among  The spiral approach is beneficial for projects with
built for specific clients or organizations. They address themselves. moderate to high risk.
unique requirements and often involve contractual
 The SDLC’s spiral model is helpful when
agreements Examples: Custom ERP solutions for
businesses, Government software systems , Military defense requirements are complicated and ambiguous.
systems  If modifications are possible at any moment
Quality System  What is the Iterative Waterfall Model?
A Quality System is a set of procedures, processes, and What is Iterative model
resources implemented by an organization to ensure that The Iterative Model is a software development approach that
products or services consistently meet customer combines the sequential steps of the traditional Waterfall
requirements and comply with applicable standards. The Model with the flexibility of iterative design. It allows for
goal of a quality system is to improve efficiency, reduce
improvements and changes to be made at each stage of the
errors, and ensure customer satisfaction by maintaining
high-quality outputs. development process, instead of waiting until the end of the
Engineering Data Records Phase of agaile model project. The Iterative Waterfall Model provides feedback paths
Engineering Data Records refer to the collection of technical  Requirement Gathering from every phase to its preceding phases, which is the main
documents, design specifications, test results, and reports  Design the Requirements difference from the classical Waterfall Model.
that are created and maintained throughout the lifecycle of a
 Construction / Iteration When to use Iterative Waterfall Model?
system or product. These records provide critical information
 Testing / Quality Assurance  The prerequisite of being well-defined and
needed for product development, manufacturing, testing,
maintenance, and compliance with regulatory standards.  Deployment comprehended.
Key components of Engineering Data Records include:  Feedback  The development team is gaining knowledge
 Design Specifications: Details about how the system about new technologies.
should be built and function. 1Customer-Centric Approach,  Certain characteristics and objectives carry a
 Drawings and Schematics: Technical diagrams that significant chance of failure in the future.
2Flexibility to Change Requirements
provide a visual representation of the product or system. Advantage of iterative model 1Phase Containment of Errors ,
3Faster Delivery (Incremental Releases)
 Test Results: Documentation of tests conducted to verify
4Improved Quality and Testing 2 Collaboration , 3 Flexibility 4 Testing and Feedback , 5 Risk
product performance and compliance.
Reduction
 Change Logs: Records of any modifications made to the 5Better Team Collaboration
product design or system during its lifecycle. Drawbacks of Iterative Waterfall Model
 Maintenance and Operating Manuals: Guidelines on how 1 Difficult to incorporate change requests,
to operate and maintain the product or system. 2 Incremental delivery not supported
 Importance of Quality System and Engineering Data 3 Overlapping of phases not supported
Records 4 Risk handling not supported
 Traceability: Helps track the history of a product from its
initial design to its final use.