What is the function of the Unix kernel?

Answer 1

The kernel is the essential center of a computer operating system, the core that provides basic services for all other parts of the operating system. A synonym is nucleus. A kernel can be contrasted with a shell, the outermost part of an operating system that interacts with user commands. Kernel and shell are terms used more frequently in Unix operating systems than in IBM mainframe or Microsoft Windows systems.

Defnition from Wikipedia:

In computer science, the kernel is the central component of most computer operating system(OS). Its responsibilities include managing the system's resources (the communication between hardware and software components). As a basic component of an operating system, a kernel provides the lowest-level abstraction layer for the resources (especially memory, processors and I/O devices) that application software must control to perform its function. It typically makes these facilities available to application programs through interprocess communication mechanisms and system calls.

These tasks are done differently by different kernels, depending on their design and implementation. While monolithic kernels will try to achieve these goals by executing all the code in the same address space to increase the performance of the system, microkernels run most of their services in user space, aiming to improve maintainability and modularity of the codebase. A range of possibilities exists between these two extremes.

Answer 2

A rather simplistic example is to liken the Linux Kernel to the hub of a bicycle wheel. The many spokes radiating outwards are akin to numerous distributions (operating systems) - of which Ubuntu, Linux Mint, are but two examples.

Answer 3

The kernel is the lowest layer of abstraction in any OS, including Linux. It takes care of the core components of a system, and manages the hardware.

Answer 4

The kernel is the memory resident part of the operating system and is not swapped out of memory.