käyttäjätilatason

Käyttäjätilatason is a Finnish term that translates to "user-space" in English. It refers to the portion of a computer's memory and execution environment that is accessible to user applications. In contrast to kernel-space, which is reserved for the operating system's kernel and device drivers, user-space is where regular programs run, such as web browsers, word processors, and games.

The primary purpose of separating user-space from kernel-space is for security and stability. When an application runs in user-space, it has limited access to the system's core functions and hardware. This prevents a faulty or malicious application from crashing the entire operating system or accessing sensitive data. If a user-space program encounters an error, it typically only affects that specific program, allowing the operating system to continue running.

When a user-space program needs to perform an operation that requires elevated privileges, such as accessing hardware or managing system resources, it must make a system call. System calls are requests made by user-space applications to the operating system kernel. The kernel then verifies the request and, if allowed, performs the operation on behalf of the application. This controlled interaction ensures that the operating system maintains control over critical system functions and protects itself from user-level interference.

The distinction between user-space and kernel-space is a fundamental concept in modern operating systems, contributing to their reliability, security, and ability to run multiple applications concurrently without compromising system integrity.