How do you identify key system components?

1 Use a problem statement

A problem statement is a concise description of the goals, requirements, and constraints of the system. It helps you focus on the essential features and functions of the system, and avoid unnecessary details and complexities. A problem statement can also help you identify the key nouns and verbs that represent the potential components of the system. For example, if the problem statement is "Design a system that allows users to book flights, hotels, and cars online", you can extract some possible components such as User, Flight, Hotel, Car, Booking, etc.

2 Apply abstraction and decomposition

Abstraction and decomposition are two principles that help you simplify and organize the system components. Abstraction means to focus on the essential characteristics and behaviors of an entity, and ignore the irrelevant details. Decomposition means to break down a complex entity into smaller and simpler parts. By applying abstraction and decomposition, you can reduce the complexity of the system, and group the components into coherent and manageable units. For example, you can abstract the User component into attributes such as name, email, password, etc., and behaviors such as login, search, book, etc. You can also decompose the Booking component into subcomponents such as FlightBooking, HotelBooking, CarBooking, etc.

3 Use diagrams and models

Diagrams and models are visual tools that help you represent and communicate the system components and their relationships. There are different types of diagrams and models that can be used for different purposes and perspectives. For example, you can use a use case diagram to show the interactions between the system and the external actors, such as users and other systems. You can use a class diagram to show the structure and properties of the components, such as attributes, methods, inheritance, association, etc. You can use a sequence diagram to show the behavior and collaboration of the components, such as messages, events, lifelines, etc.

4 Apply design patterns and principles

Design patterns and principles are proven solutions and guidelines that help you solve common design problems and improve the quality of the system. They can help you identify and refine the system components, and ensure that they are consistent, cohesive, and loosely coupled. For example, you can apply the Single Responsibility Principle (SRP) to ensure that each component has only one reason to change, and does not have too many responsibilities. You can apply the Open-Closed Principle (OCP) to ensure that each component is open for extension, but closed for modification. You can also use design patterns such as Factory, Strategy, Observer, etc., to implement common behaviors and interactions among the components.

5 Validate and iterate

The final tip is to validate and iterate your system components, and make sure that they meet the needs and expectations of the stakeholders, such as users, clients, managers, etc. You can use various methods and techniques to validate your system components, such as reviews, tests, prototypes, feedback, etc. You can also use an iterative and incremental approach to design your system components, and make changes and improvements based on the validation results. By validating and iterating your system components, you can ensure that they are relevant, reliable, and robust.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?