Operating System

The User Mode is concerned with the actual interface between the user and the system.

The Kernel Mode is concerned with everything running in the background.

It is a software code that reside in central core of OS. It has complete control over system.

When operation system boots, kernel is first part of OS to load in cpu.

Kernel remains in cpu for entire duration of computer session. The kernel code is usually loaded in to protected area of cpu.

It allocates the Kernel’s processing time to various processes.

It grants permission to use computer system resources to each process.

It handles all requests from the various  hardware devices which compete for kernel services.

It allocates space in memory for all users  of kernel service.

The programmatic way in which a computer program/user application requests a service from the kernel of the operating system on which it is executed.