Processes and threads are essential abstractions provided by modern operating systems, enabling multitasking and resource sharing on computers. A process is an instance of a program being executed, allowing the CPU to switch between multiple tasks, thereby giving the illusion of simultaneous execution. Threads, on the other hand, allow multitasking within a single process, sharing the same memory space, and are more efficient than process context switches. The article illustrates the differences and functionalities of processes and threads through examples, such as the connection-per-process model used by Postgres and the thread-per-connection model by MySQL, highlighting how these systems manage multitasking and performance. Additionally, it touches upon the role of CPU and RAM in executing instructions, the concept of context switching, and the use of connection pooling to manage high connection demands in databases. Understanding these concepts helps in designing software that efficiently balances performance and resource management.