2nd year computer science notes Chapter 2 System Development Life Cycle

KPK Grade 12 Computer Science Notes

2nd year computer science notes Chapter 2 System Development Life Cycle for kpk board Peshawar. ics computer science notes part 2 Chapter 2.

Chapter 2 System Development Life Cycle

Q.1 Define software development life cycle (SDLC). What are its objectives?

SOFTWARE DEVELOPMENT LIFE CYCLE (SDLC):

DEFINITION:

The software development life cycle (SDLC) is a conceptual model used in project management that describes the stages involved in an information system development project from an initial feasibility study through maintenance of the completed application.

OBJECTIVES OF SDLC:

The objectives of the software Development Life Cycle (SDLC) are as follows:

1. Delivery of quality software that meets customer expectations.
2. Delivery of inexpensive and cost-effective software which are easily maintainable.
3. Maximize productivity in terms of the software systems delivered.
4. One of the major objectives of SDLC is to establish an appropriate level of management authority to direct, coordinate, control, review and approve the software development project.
5. SDLC should ensure project management accountability.
6. Proper documentation of all the requirements needed for the development of a new software system.
7. Ensuring that projects are developed within the current and planned information technology infrastructure.
8. SDLC should identify the potential project risks in advance so that the proper planning should be done.

Q. 3 Why is the software development life cycle important for the development of software?

Importance of Software Development Life Cycle

Following points summarize the importance of the use of SDLC:

• SDLC is important because it breaks down the entire life cycle of software development into phases thus making it easier for the development team members to easily evaluate each part of software development.
• SDLC makes it easier for programmers to work concurrently on each phase.
• It provides a rough time estimate that when the software will be available for use.
• It delivers quality software which meets or exceeds customer expectations.
• It provides the basic framework for the development of quality software.
• SDLC helps the project managers to establish project management and be followed strictly during system development. 
• SDLC clearly defines and assigns the roles and responsibilities of all the involved parties.
• It ensures that the requirements for the development of the software system are well defined and subsequently satisfied

Q. 4 Who are stakeholders of SDLC? Describe their responsibilities.

STAKEHOLDERS OF SDLC:

Those entities which are either within the organization or outside of the organization that sponsors a project, or have an interest or have the intention to get it after its successful completion, or may have a positive or negative influence in the project completion called stakeholders. Project stakeholders include the customer, the user group, the project manager, the development team and the testers.

All those who have some interest in the project can be considered as stakeholders of that project. The individuals as well as the organizations that are actively involved in the project, or whose interest may be affected as a result of project execution or project completion are the part of stakeholders. The project management team must identify the stakeholders determine their requirements, expectations and mange their influence about the requirements to ensure a successful project.

RESPONSIBILITIES OF STAKEHOLDERS:

The basic role of the stakeholders are:

• – For the development of software, resources such as time, money, equipment etc are needed which should be provided to the project team by the stakeholders.
• – Stakeholders educate the developers about their business.
• – They spend more time to provide information and clarify requirements to the analyst and developers.
• – The stakeholders should be specific and precise about the requirements.
• – Make timely decisions.
• – Respect a developer’s assessment of cost and feasibility.
• – Set requirements priorities.
• – Review and provide timely feedback.
• Promptly communicate changes to requirements.

Q.8) What is meant by the term software requirement? Differentiate between functional and non-functional requirements.

Answer:

SOFTWARE REQUIREMENTS:

Software requirements is a field within software engineering that deals with establishing the needs of stakeholders that are to be solved by software.

DIFFERENCE BETWEEN FUNCTIONAL AND NON FUNCTIONAL REQUIREMENTS:

FUNCTIONAL REQUIREMENTS:

Functional requirements are those requirements of a software system which describes a function of a software system or its component. It includes calculations, technical details, data manipulation and processing and other specific functionality that define what a system is supposed to accomplish. Examples of functional requirements are:

a) Interface requirements

•   – Field accepts numeric data entry
•   – Field only accepts dates before the current date.
•   – Screen can print on-screen data to the printer

b) Business requirements:

•   – Data must be entered before a request can be approved.

c) Regulatory/Compliance requirements:

•   – The database will have a functional audit trail.
•   – The system will limit access to authorized users.
•   – The spreadsheet can secure data with an electronic signature.

d) Security requirements:

•    – Member of the data entry group can enter requests but not approve or delete requests.
•   – Members of the /managers group can enter or approve a request, but not delete requests.
•   – Members of the administrator group cannot enter or approve a request but can delete request.

NON FUNCTIONAL REQUIREMENTS:

Non- functional requirements are those requirements which specify criteria for the judgement of the operations of a system. It describes how well the system performs its duties. Non-functional requirements are often called qualities of a system. These requirements depend upon the nature of the software.

Different types of non-functional requirements are:

• 1. Accessibility Requirements
• 2. Accuracy Requirements
• 3. Backup and Recovery Requirements
• 4. Memory capacity Requirements
• 5. Compatibility Requirements
• 6. Error- handling Requirements
• 7. Maintainability Requirements
• 8. Performance Requirements
• . Security Requirements

Q.9) Design a flowchart for the following algorithm.

sum=0, N=5
x=1
while x ≤ N do 
sum = sum + x
x = x + 1
end while 
print sum

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