What does User Mode refer to in a computer's operating system?

User Mode refers to a specific operational mode of a computer's processor that offers an isolated environment for running applications. In this mode, each application is provided with its own virtual address space, which serves several crucial purposes.

The primary advantage is that it enhances the stability and security of the operating system. By operating in User Mode, applications cannot directly access the hardware or system resources in a way that could lead to crashes or malfunctions affecting other applications or the operating system itself. This isolation ensures that if one application encounters an error, it does not compromise the functionality of other applications or the overall system, thereby enhancing reliability.

This mode contrasts with Kernel Mode, where the operating system has complete control over the hardware and can execute any command without restrictions. However, this freedom poses a risk; if an error occurs at this level, it can lead to system-wide crashes. Consequently, User Mode is a fundamental aspect of modern operating systems, facilitating multitasking and stability while protecting system integrity.