Introduction of System Analysis and Design

What is System Analysis and Design?

System Analysis and Design (SAD) is a structured process used to develop and maintain information systems. It involves analyzing a problem, designing a solution, and implementing that solution using system components like hardware, software, data, and users.

Key Concepts:

Purpose of SAD:

• To build efficient and reliable information systems.
• To solve organizational problems through technology.
• To ensure system requirements are correctly gathered and implemented.

Example of SAD:

Example: Online Examination System

Phases of SAD:

1. Preliminary Investigation
2. System Analysis
3. System Design
4. Development
5. Testing
6. Implementation
7. Maintenance

Diagram: System Analysis and Design Process

Why SAD is Important?

• Ensures the system meets user needs
• Reduces cost and errors
• Improves system quality and efficiency
• Provides documentation and long-term support

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Definition of System:

A system is a set of interrelated components working together toward a common goal by accepting inputs and producing outputs in an organized transformation process.

Fundamentals of a System:

Block Diagram of a System:

Example: Library Management System

Importance of Understanding System Fundamentals:

• Helps in problem identification
• Ensures better design
• Improves efficiency and effectiveness
• Aids in system integration

Important term related to system

1. System

A system is a set of interrelated components working together toward a common goal.

• Example: A college management system includes modules for student data, attendance, and fee management.

2. Subsystem

A subsystem is a smaller component of a larger system, performing a specific task.

• Example: In a hospital system, the billing department is a subsystem.

3. Input

The data or material received by the system for processing.

• Example: Student details entered during admission.

4. Process

The operation or action performed on input to convert it into output.

• Example: Calculating student grades from marks.

5. Output

The result or information produced by the system after processing.

• Example: Report card or bill.

6. Feedback

Information about the output that is used to improve the system.

• Example: User complaints used to improve the website interface.

7. Control

Controls are rules or policies that guide the system and ensure it operates correctly.

• Example: Students must pay fees before accessing results.

8. Boundary

Defines the limits of the system, separating it from the external environment.

• Example: A school's library system does not handle student fees (outside its boundary).

9. Environment

Everything outside the system boundary that interacts or affects the system.

• Example: Government policies affecting school systems. 

10. Interface

The point of interaction between two systems or between users and the system.

• Example: Login screen of a student portal.

11. Data

Raw facts or figures that are processed to generate information.

• Example: Marks, names, ID numbers.

12. Information

Processed or organized data that is meaningful and useful.

• Example: Average class performance report.

13. System Analyst

A professional who studies, analyzes, designs, and implements systems.

• Example: An IT expert designing a hospital record system.

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Classification of System in System Analysis and Design

Systems can be classified based on their nature, structure, functionality, and interactions with the environment. Understanding these classifications helps system analysts choose the right design and development approach.

1. Physical vs. Abstract System

2. Open vs. Closed System

In reality, no system is fully closed; all systems have some interaction with their environment.

3. Deterministic vs. Probabilistic System

4. Man-Made vs. Natural System

5. Permanent vs. Temporary System

6. Adaptive vs. Non-Adaptive System

Diagram: Classification of System

Why Classification is Important in SAD?

• Helps in understanding system behavior and complexity
• Aids in selecting appropriate design and implementation techniques
• Improves system performance and maintainability

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Real-Life Business Subsystems

In System Analysis and Design, a subsystem is a smaller part of a larger system that performs specific tasks and contributes to the overall system functionality.

A business system (like an organization) is composed of multiple subsystems, each handling specific functions such as finance, marketing, HR, etc.

Definition of Subsystem:

A subsystem is a component of a larger system that has its own function but works together with other subsystems to achieve the overall goal.

Example: Real-Life Business – University as a System

All these subsystems interact with each other. For example, the finance subsystem collects fees and passes student status to the academic subsystem.

Example: Real-Life Business – E-commerce Company

 Diagram: Real-Life Business System with Subsystems

Each block here is a subsystem that performs a specific role, but collectively they help the main system (e.g., university) function effectively.

Why Subsystems are Important:

• Divide and conquer: Breaks down complex systems into manageable units
• Improves efficiency: Each subsystem specializes in its task
• Easier maintenance: Changes can be made in one subsystem without affecting others
• Supports modular design: Encourages reuse and scalability

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Real-Time System

What is a Real-Time System?

A Real-Time System (RTS) is a system that must respond to inputs or events within a strict time limit. The correctness of the system depends not only on producing the correct result, but also on producing it at the correct time.

Key Characteristics of Real-Time Systems:

Types of Real-Time Systems:

Real-Time System Example: Airbag Control System in Cars

Diagram: Real-Time System Workflow

More Real-Life Examples of Real-Time Systems:

Why Real-Time Systems are Important?

• Safety-Critical Operations (e.g., airbag systems)
• Timely Decision Making
• Constant Monitoring and Response
• Increased Efficiency and Automation

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Distributed System

Simple Definition:

A Distributed System is like a team of computers (or devices) working together over a network to achieve a common goal, but they look and feel like a single system to the user.

In Short:

A Distributed System is like a team of workers in different rooms of a building — each doing a part of the job, but to the customer, it feels like one smooth service.

Human-Friendly Explanation:

Imagine you order food from a food delivery app (like Zomato or Swiggy):

• One server shows the menu
• Another server checks your location
• Another one processes payment
• Another one manages delivery

All these parts work together, but they are running on different computers in different places. Still, to you, it feels like one single app — that’s a distributed system

Features (in simple terms):

Real-Life Examples of Distributed Systems:

Diagram (Simple View of a Distributed System)

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Development of a Successful System

Developing a successful system involves a step-by-step process to ensure the system is useful, user-friendly, reliable, and solves the real problem for which it is created.

Definition:

The development of a successful system is the structured process of analyzing, designing, building, testing, and implementing an information system that meets the objectives of users and organizations effectively and efficiently.

Key Stages in Successful System Development (with Explanation):

Factors for System Success:                                                 

Diagram: Development of a Successful System

Real-Life Example: School Management System

• Problem: Paper-based attendance and marks taking time
• Solution: Develop a digital School Management System
• Result: Faster reporting, better tracking, parent access to progress reports

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