A kernel is a computer program that is at the core of an operating system and serves as the main interface between the computers physical hardware and the processes running on it). It is responsible for managing the hardwares resources and executing software programs, as well as overseeing the interactions between the hardware and software components). The kernel enables multiple applications to share hardware resources by providing access to CPU, memory, disk I/O, and networking.

The kernel is loaded into memory when an operating system is loaded and remains in memory until the operating system is shut down again. It is named a kernel because it operates inside the operating system, just like a seed inside a hard shell. The kernel is one of the initial programs loaded up on memory before the boot loader. The boot loader is responsible for translating instructions for the central processing unit and managing memory as well as peripherals such as keyboards and monitors.

The kernel has several important jobs, such as process and memory management, disk storage, and low-level networking. It decides which process should be allocated to the processor to execute and which process should be kept in main memory to execute. The kernel has a process table that keeps track of all active processes. It controls all of the main functions of the hardware, whether its a tablet, desktop, server, or any other kind of device.

There are different types of kernels, including monolithic kernels and microkernels). Monolithic kernels, which have traditionally been used by Unix-like operating systems, contain all the operating system core functions and the device drivers). A monolithic kernel is one single program that contains all of the code necessary to perform every kernel-related task). Microkernels, on the other hand, provide a small set of simple hardware abstractions and use applications called servers to provide more functionality.