It is the part of the software that provides many applications with secure access to the computer hardware, which is limited, and the kernel determines when and for how long a program can operate on a certain part of the hardware. Kernels can be categorized as single and dual kernels and microkernels.
Strictly speaking, a kernel is not a necessary part of a computer system. A kernel, is the core of an operating system. It is responsible for managing the system's processes, memory, device drivers, files, and network systems, and determines the performance and stability of the system.
Programs can be tuned directly into the computer for execution; such a design indicates that the designer does not wish to provide any hardware abstraction or operating system support, and it is common in the design of early computer systems.
Eventually, auxiliary programs, such as program loaders and debuggers, were designed into the core of the machine or solidified in read-only memory. As these changes occurred, the concept of the operating system kernel became clear.