The process of activating the input of the operating system into the main memory is known as;

The process of activating the input of the operating system into the main memory is known as booting. Booting refers specifically to the sequence of events that occurs when a computer is powered on, during which the system's firmware initializes hardware components and loads the operating system into the main memory. This process is critical because it prepares the computer to perform its functions and interact with users or applications.

When a computer boots, it typically goes through a series of checks (often called POST, or Power-On Self-Test) to ensure that all the hardware components are functioning correctly. After that, the operating system is located typically on the hard drive or solid-state drive and loaded into RAM, allowing the computer to operate and execute programs.

Other terms mentioned, like startup and shutdown, refer to broader concepts but do not specifically define the act of loading the operating system into memory. Startup can encompass many elements of the entire initiation process, while shutdown pertains to powering down the system safely. Program administration is not relevant in this context as it deals more with managing software programs rather than the foundational process that allows a computer to begin its operation.