Which of the following components is NOT part of servers?

The operating system is a critical software component that provides the necessary interfaces and management tools for computer hardware, but it is not a physical part of the server itself. Servers are typically comprised of hardware components, which include the CPU, memory, and network components like switches. While the operating system is essential for a server to function, facilitating communication between the hardware and the software applications, it remains distinct from the tangible parts of the server.

In contrast, the components identified as CPU, memory, and switches are all integral hardware elements that directly contribute to the server's performance and capabilities. The CPU acts as the brain of the server, executing instructions and processing data. Memory (RAM) provides the temporary storage required for tasks currently being processed, ensuring that the CPU has quick access to the necessary information. Switches facilitate network communication, allowing servers to connect and communicate within a wider network. Thus, the operating system's nature as software rather than hardware clarifies why it does not belong to the components of servers in the same category as the other options.