This question is best answered by countering: What is a kernel not? The kernel is not the core of a processor, it’s the core of the operating system. A kernel is also not an API or framework.
Multikernel operating systems can use various cores of a multicore processor like a network of independent CPUs. How does that work? It comes down to the special structure of the kernel, which is composed of a series of different components:Since the kernel’s lowest layer is machine oriented, it can communicate directly with the hardware, processor, and memory. The functions of the kernel vary among its five layers, from processor management to device management. The highest layer cannot access machines, and instead is responsible for interfacing with software.Application programs run separately from the kernel in the operating system and merely draw on its functions. Without the kernel, communication between programs and hardware wouldn’t be possible.Several processes can run simultaneously thanks to the multitasking kernel. But it’s generally the case that only one action can be processed by the CPU at one time – unless you’re using a multicore system. The rapid change in processes that gives the impression of multitasking is taken care of by the scheduler.
me: "huh, why do I have a directory called 'evils' in my backups" also me: "and why is it filled with Dockerfiles tied to kernel versions for arm64?"— Jim Perrin (@SteamPoweredDM) May 05, 2021
From these components follow the four functions of the kernel:Memory management: Regulates how much memory is used in different places.Process management: Determines which processes the CPU can use, as well as when and how long they’re used for.Device driver: Intermediates between hardware and processes.System calls and security: Receives service requests from the processes.
When implemented properly, the functions of the kernel are invisible to users. The kernel works in its own setting, the kernel space. On the other hand, files, programs, games, browsers, and everything that the user sees are located in the user space. Interaction between these two use the system call interface (SCI).