In computer science, a kernel is a computer program that is at the core of an operating system and manages the operations of the computer and hardware. It is responsible for accessing computer resources such as RAM and I/O devices. The kernel is the portion of the operating system code that is always resident in memory and facilitates communication between software (user-level applications) and hardware (CPU and disk memory) ). The kernel decides which process should be allocated to the processor to execute and which process should be kept in main memory to execute.
There are different types of kernels, including:
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Monolithic Kernel: This type of kernel is used by Unix-like operating systems and contains all the operating system core functions and device drivers. It is one single program that contains all of the code necessary to perform every kernel-related task).
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Microkernel: This type of kernel is designed to be as small as possible and only contains the essential functions of the operating system. It provides a small set of simple hardware abstractions and uses applications called servers to provide more complex services.
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Hybrid Kernel: This type of kernel is a combination of both monolithic and microkernels. It takes advantage of the speed of monolithic kernels and the modularity of microkernels. A hybrid kernel can be understood as the extended version of a microkernel with additional properties of a monolithic kernel.
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Exokernel: This type of kernel provides a minimalistic interface between hardware and software, allowing applications to have direct access to hardware resources.
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Nanokernel: This type of kernel is even smaller than a microkernel and only provides basic hardware abstractions.
In summary, a kernel is a crucial component of an operating system that manages the operations of the computer and hardware. It provides an interface between user-level applications and hardware and decides which process should be allocated to the processor to execute. There are different types of kernels, including monolithic, microkernel, hybrid, exokernel, and nanokernel.
