Kernel (operating system)

The kernel is the central component of a computer operating system, the program that runs with the highest level of privilege and mediates every interaction between application software and the underlying hardware. It manages memory allocation, schedules which process gets access to the processor, and coordinates input and output through device drivers, so that programs never touch hardware resources directly. Because it stays resident in memory for the entire time a machine is running, the kernel also enforces isolation between processes, preventing one running program from corrupting another or from overwriting resources it does not own. Different kernel designs, monolithic, microkernel and hybrid, trade off how much of this work happens in one privileged block versus separate smaller services, a debate that has shaped operating system architecture for decades.