Problem Statement
Explain the difference between kernel mode and user mode in an operating system and why the distinction matters for security.
Explanation
In an operating system the CPU can operate in at least two modes: user mode and kernel mode. In user mode applications execute with limited privileges and cannot execute critical instructions or access sensitive hardware directly. In kernel mode the OS core and trusted code run with full privileges and can manage hardware, memory, interrupt handling and system resources. This separation is important for security because it prevents user‐level code (which may be malicious or buggy) from harming the system, accessing other processes’ memory or performing privileged operations. By restricting risky operations to kernel mode the OS reduces its attack surface.
