Chapter - 2, System Development Life Cycle, Computer Science Key Point Notes, HSSC-II (12th Class)

12th Class (HSSC-II) Computer SLO Based Key Point Notes

(National Book Foundation - As Federal Textbook Board, Islamabad 

Based on National Curriculum Pakistan 2024-2025 and Onward prescribed by Federal Board of Intermediate and Secondary Education, Islamabad, and All Pakistan Boards) 

Unit 2: System Development Life Cycle

2.1.1 A System:

• A system is a set of components (hardware/software) for collecting, creating, storing, processing, and distributing information.
• The registration of students can be a procedure in an education system.
• An Examination system determines the overall performance of each student as a final result.
• A billing system can be used by an organization to send invoices and receive payments from customers.
• A payroll system is used to manage employees' salaries.

2.1.2 System Development Life Cycle (SDLC):

It is a problem-solving process through which a series of steps or phases helps to produce a new computer system.

Importance of SDLC:

• It delivers quality software that meets the system requirements.
• It ensures that the requirements for the development of the software system are well-defined and subsequently satisfied.
• It delivers a cost-effective system.
• It maximizes the productivity.
• Provides a framework for a standard set of activities and deliverables

2.1.3 Objectives of SDLC:

• SDLC establishes an appropriate level of management authority to direct, coordinate, control, review, and approve the software development project.
• SDLC identifies the potential project risks in advance so that proper planning should be done in early.
• It ensures that high-quality systems are delivered.
• It maximizes productivity.

2.1.4 Stakeholders of SDLC:

• Stakeholders of SDLC are those entities or groups that are either within the organization or outside of the organization that sponsor, plan, develop, or use a project.
• Stakeholders may be users, managers, and developers.
• It is the duty of the project manager to identify the stakeholders, determine their requirements, and expectations to ensure a successful project.

2.1.5 SDLC Phases or Steps:

1. Defining problem
2. Planning
3. Feasibility Study
4. Analysis
5. Requirement Engineering
6. Design
7. Coding
8. Testing / Verification
9. Deployment / Implementation
10. Maintenance / support

1- Defining Phase:

• In this phase, the problem to be solved or the system to be developed is clearly defined.
• The requirements are documented and approved by the customer or company.
• It is very important to identify all requirements in order to develop the project successfully.
• Example: A student Examination System needs to be developed to cover all aspects from conducting the examination and generating results.

1- Planning Phase:

During the planning phase:

• The objective of the project is determined
• The requirements to produce the project are considered.
• An estimate of resources, such as personnel and costs, is prepared.
• All the information is analyzed to get alternative solutions, if any.
• The information is assembled into a project plan and presented to management for approval.

3- Feasibility study:

• It is the analysis and evaluation of a proposed project, to determine, whether it is technically, financially, legally, and operationally feasible within the estimated cost and time.
• It is used to assess the strengths and weaknesses of the proposed project.

It is divided into the following types or forms:

• Technical Feasibility: (Determines the level of and type of technology needed for the system)
• Financial Feasibility: (Can we complete the project within the budget or not)
• Operational Feasibility: (How well the proposed system will solve the problems?)
• Legal Feasibility: (Can we handle this project as cyber law/Copyright and other regulatory framework/compliances)
• Schedule Feasibility: (Decide whether the project can be completed within the given schedule or not)

4- Analysis Phase:

• During this phase, the project team determines the end-user requirements and provide their expectation from the new system.
• The In-charge of the project team must decide whether the project should go ahead with available resources or not.
• It is also looking at the existing system to see what and how it is doing its job.

During this phase, the project team asks the following questions:

• Can the proposed project be developed with the available resources and budget?
• Will this system improve the performance of an organization?
• Does the existing system need to be replaced?

Example: The Student Examination System is analyzed for development. The team may visit the educational institute to study the existing system to suggest improvements.

5- Requirement Engineering

• It is the process of determining user expectations for a new or modified system/software.
• It is a set of activities used to identify and communicate the purpose of a software/system.

It consists of the following steps:

1. Requirement gathering:

It is the first part of any system development process in which meetings with customers are arranged, and their requirements and demands are analyzed which are of two types:

• Functional Requirements which specify the software functionality that the developer must build into the system to enable users to accomplish their tasks.
• Non-Functional Requirements specify the criteria for the judgment of the operation of a system which describes how the system performs its duties.

2. Requirement Validation:

• It is concerned with examining the gathered requirements to certify that they meet the intentions of the stakeholders.
• It reviews the requirements and ensures that the requirements are complete and accurate.

3. Requirement Management:

• It is performed to ensure that the software continues to meet the expectations of the users.
• It needs to gather new requirements that arise from changing expectations, new regulations, or other sources of change.

Functional Requirements vs Non-Functional Requirements

6- Design Phase:

• It is the architectural phase of system development in which the project team develops a logical design for data storage and processing.
• The project team designs a mock-up or dummy user interface, for which the developers write the actual code to make it functional.

The design phase consists of two different structures:

1. Algorithm:

It is a step-by-step procedure which is used to solve a problem.

2. Flowchart:

The diagrammatic representation of an algorithm is called a flowchart.

Flow chart Symbols

Example:
The algorithm that inputs marks and prints the message “PASS” or “FAIL”. Passing marks are 33.

STEP 1: START
STEP 2: Input marks (M)
STEP 3: Comparing the marks (M) with 33 i.e.
            IF M >= 33 THEN PRINT “PASS” OTHERWISE PRINT “FAIL”
STEP 4: STOP.

Flow Chart

7- Coding / Construction:

• During this phase, the developers/programmers create the database, write the code in a programming language for data processing, and design the actual user interface.
• Test data is prepared and processed as many times as necessary to refine the code.
• Coding is also called computer programming.

Example:

            #include <iostream.h>

            void main(void)

            {

                        int marks;

                        cout<<”Enter Marks;

                        cin<<marks;

                        if(marks >= 33)

                                    cout<<”PASS”;

                        else

                                    cout<<”FAIL”;

            }

8- Testing/Verification

• The process of executing programming modules to find errors is called testing.
• During this phase, the system is tested for functionality and performance.
• The purpose of testing is to evaluate an attribute or capability of a program or system and determine whether it meets its required results.
• Testing/verification the software is actually operating the software under controlled conditions and checking and evaluating the result against pre-specified requirements.

9- Deployment / Implementation

It is a set of activities that are used to make the software/system available for use.

Activities involved in this phase are:

i.     Installation and activation of the hardware and software.

ii.    Train the users on the developed system.
iii.   Conversion from the old system to the new system.

Deployment Methods:

1. Direct Implementation / Deployment:

• It involves the old system being completely dropped and the new system being completely implemented at the
same time.

2. Parallel:

• This method involves operating both systems together for a period.
• This method allows any major problems with a new system to be encountered and corrected without loss of any information.

3. Phased:

• This method involves the new system being gradually introduced and the old system being progressively discarded.

4. Pilot:

• In this method, the new system is installed for a small number of users to learn, use, and evaluate.
• Once the system is performed satisfactorily, the new system is installed and used by all.

10- Maintenance / Support

• Maintenance can be either repairing or modification or some enhancement in the existing system.
• The performance of a system is monitored continuously and when problems or modifications are identified, the system may reenter the planning phase which will continue until a complete solution is provided to the customer.

2.1.6 Personnel Involved in SDLC and their Role

Management Personnel or Team:

The roles of a good management team are to:

• Provide consistency of success of the software with regard to time, cost, and quality.
• Ensure that customer expectations are met.
• Collect information for future use.
• Provide a method of thought for ensuring all requirements are addressed through a comprehensive work definition process.
• Reduce risks associated with the project.

Project Manager:

• Project manager responsible for planning, execution, and closing of any project.
• He/she should be familiar with the whole software development life cycle process.

The key roles of a project manager are:

• Developing the project plan.
• Managing the project budget.
• Managing the project stakeholders.
• Managing the project team.
• Managing the project schedule.
• Managing the project conflicts.

System Analyst

• A system analyst studies the problem, plans the solutions, and coordinates the development process to meet all the requirements of customers.
• System analyst has expertise in a variety of programming languages, operating systems, and computer hardware platforms

Key roles of system analyst are:

• Plan a system flow
• Interact with customers to learn and document requirements.
• Define technical requirements
• Interact with designers to understand software limitations.
• Help programmer.
• Manage system testing
• Documented requirements and contributed to user manuals.

Programmer

A programmer is a technical person who writes computer programs in a computer programming language to develop software.

The key roles of programmers are:

• Writing, testing, and maintaining the instructions of computer programs.
• Updating, modifying, and expanding existing programs.
• Testing the code by running to ensure its correctness.
• Preparing graphs, tables, and analytical data displays which show the progress of a computer program.

Software Tester:

• A software tester is a computer programmer with having specialty in testing computer programs using different testing techniques.
• Tester is responsible for understanding, and creating test scenarios, and test scripts, preparing test data, executing test scripts, and reporting defects and results.
• Meeting with development managers to discuss software specifications and controls.
• Using the software as intended to analyze its functional properties.
• Designing manual and automated test procedures to evaluate each software product.
• Building, coding, and implementing software evaluation test programs.
• Running test programs to ensure that testing protocols evaluate the software correctly.
• Tweaking the software testing systems for maximum performance.
• Finalizing and documenting testing procedures.
• Completing final tests and creating test reports.
• Presenting test reports to management and suggesting software fixes.

The responsibilities of the software tester include:

• Creation of test designs, test processes, test cases, and test data.
• Carry out testing as per the defined procedures.
• Participate in walkthroughs of testing procedures.
• Prepare all reports related to software testing carried out.
• Ensure that all tested-related work is carried out as per the defined standards and procedures.

Customers

• A customer is an individual or an organization that is the buyer or user of the software product.

• Customers are also called clients.

• The difference between customer and client is that the customers purchase the software products and the clients purchase services.

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