User and Kernel mode

In the Windows operating system, user mode and kernel mode are two distinct execution modes that provide different levels of access to system resources and hardware.

User Mode

User mode is the default mode of operation for most applications and processes. When a program runs in user mode, it has limited access to system resources and cannot directly access hardware resources. Instead, it relies on system calls to request services from the operating system.

Kernel mode

Kernel mode, on the other hand, is a privileged mode of operation that provides direct access to system resources and hardware. The operating system's kernel runs in this mode and is responsible for managing system resources and providing services to user-mode applications.

Modus Operandi

When a program needs to perform a privileged operation, such as accessing hardware resources or modifying system settings, it must switch to kernel mode by making a system call. The operating system then performs the requested operation on behalf of the program and returns control to user mode.