Anyone who uses a device that is controlled by an operating system is working with a kernel, though often without realizing it. The kernel is the core component that manages the operations of the computer and its hardware. It serves as the interface between software and hardware. Whenever a system starts, the Kernel is the first program that is loaded after the bootloader because the Kernel has to handle the rest of the things of the system for the Operating System. The Kernel remains in the memory until the Operating System is shut down. Operating system Kernels act as a bridge between applications and data processing performed at the hardware level using inter-process communication and system calls. When a process makes a request to the Kernel, then it is called System Call.
Functions of a Kernel
Following are the functions of a Kernel:
- The Kernal allows access to computer resources. A Kernel can access various computer resources like the CPU, I/O devices and other resources. It acts as a bridge between the application and the resources of the system.
- The Kernal is responsible for managing the resources in the system. It can allow resources to be shared amongst processes as requested.
- The kernel is responsible for managing the system memory. Every process needs some memory space so the kernel can be allocated and deallocate the requested amount for its execution.
- The kernel manages all of the devices connected to the systems and all allocation of these devices to certain processes are handled by the kernel.
Type of Operating system Kernel
According to design and functionality, we have many kinds of kernels.
Monolithic Kernels: In a monolithic kernel, all operating system services run along the main kernel thread, which also resides in the same memory space. By doing this, it allows for faster execution of the process but the disadvantage is that the size of the Kernel is increased.
Microkernels: Microkernel used both kernel and userspace to run all the system processes. As we are using User Space and Kernel Space separately, so it reduces the size of the Kernel and this, in turn, reduces the size of the Operating System. Since we are using User Space and Kernel Space separately, so the communication between these can reduce the overall execution time.
Hybrid Kernels: A hybrid kernel is an extended version of the micro-kernel with the addition of some functionality of the Monolithic kernel built-in. A hybrid kernel is divided into services the same as a micro-kernel, and they are all executed in the same kernel space as the Monolithic kernel. It makes use of the speed of Monolithic Kernel and the modularity of Microkernel.
Nano Kernels: In a Nanokrnel, as the name suggests, the whole code of the kernel is very small i.e. the code executing in the privileged mode of the hardware is very small. The term nanokernel is used to describe a kernel that supports a nanosecond clock resolution.
Exo Kernels: In this type of kernel, the resource protection is separated from the management and this, in turn, results in allowing us to perform application-specific customization. Allocate physical hardware resources such as processor time and disk block to other programs, which can link to library operating systems that use the kernel to simulate operating system abstractions.
Difference between Operating System and Kernel
A kernel is an essential part of an operating system. It’s an always-running program that controls everything and manages hardware resources and program execution. An operating system consists of a kernel and some additional software that allows for user interaction. This might include a graphical user interface, shell, web browsers, and so on.