What is kernel?
The central module of an operating system. It is the part of the operating system that loads first, and it remains in main memory. Because it stays in memory, it is important for the kernel to be as small as possible while still providing all the essential services required by other parts of the operating system and applications. Typically, the kernel is responsible for memory management, process and task management, and disk management.
When a computer crashes, it actually means the kernel has crashed. If only a single program has crashed but the rest of the system remains in operation, then the kernel itself has not crashed.. A crash is the situation in which a program, either a user application or a part of the operating system, stops performing its expected function(s) and responding to other parts of the system. The program might appear to the user to freeze. If such program is a critical to the operation of the kernel, the entire computer could shut down.
Categories of Kernels
Kernels can be classified into four broad categories: monolithic kernels, microkernels, hybrid kernels and exokernels.
The latest stable version of the Linux kernel is 2.6.17.8
