The mode in which there is an unconditional, unrestricted and full permission to access the system’s hardware by the current executing piece of code is known as the kernel mode. The mode in which there is no means of accessing the system’s hardware directly by the current piece of code is also known as the user mode.
The kernel mode is a very powerful and impactful mode which means that it can refer to any memory block of the system and can also orders to execute an instruction to the CPU. The user mode is standardized and normal viewing mode which means that it cannot reference to any memory block or execute any information on its own as it requires some Application Protocol Interface (API) to do these tasks.
The kernel mode is the most unrestricted and candid mode that a system can have which means that only the trustable sources can be allowed to operate in this very mode. The user mode is more like a generic mode that can have, which means that any user can access this mode for a particular system and is allowed to operate in this particular mode.
As the kernel mode is very important and candid this means that if the system crashes in this mode then it could be very fatal and increases the complexity. As the user mode is quite general and user-friendly this means that even if the system crashes in this mode then it is not fatal at all and can simply restart the session.
The kernel mode is very crucial to the system as well as the system programmer so everything that runs easily runs on your PC might not run here because its purpose is to employ hardware for a particular task. The user mode is user friendly space where all the general code will definitely execute.