What is the difference between event-driven and process-based architecture?

Event-Driven and Process-Based are two different architectural models for implementing applications, particularly in the area of server software.

With a process-based architecture, a new process is started for each incoming client request to process the request. This means that each time a new request comes in, a new instance of the process is started to handle the request. Each of these processes is independent of each other and has its own memory space, CPU time, and environment. The processes can communicate with each other, but with some latency and low efficiency.

In contrast, the event-driven architecture is based on a single process instance that processes a loop of queues on which asynchronous events arrive from multiple sources, such as network connections or user interactions. The loop processes the events asynchronously and maps them according to predefined actions in the application. This allows handling many requests simultaneously without starting new processes, which is typically faster and more efficient than the process-based architecture.

Event-driven architectures are particularly suitable for applications that have to process a large number of incoming requests, such as web servers or messaging systems. Process-based architectures tend to be used for applications that require intensive computing power, such as scientific or mathematical applications.