Monikäyttöjärjestelmät

Monikäyttöjärjestelmät, known in English as multitasking operating systems, are computer operating systems that allow a single user to perform multiple tasks or run multiple programs simultaneously. This is achieved by the operating system's ability to rapidly switch the central processing unit's (CPU) attention between different tasks. Each task is allocated a small slice of CPU time, and the system switches between them so quickly that it creates the illusion of concurrent execution for the user.

The core mechanism behind multitasking is process scheduling, where the operating system determines which process gets to use the CPU at any given moment. This scheduling can be based on various algorithms, such as round-robin, priority-based, or shortest-job-first, each aiming to optimize factors like response time, throughput, or fairness. Preemptive multitasking, a common form, allows the operating system to interrupt a running process and allocate the CPU to another process, ensuring that no single task monopolizes the system's resources.

Multitasking significantly enhances user productivity and system efficiency. Users can perform actions like downloading files in the background while working on a document in the foreground, or have multiple applications open and accessible without needing to close and reopen them. This capability is a fundamental feature of modern operating systems, including Windows, macOS, Linux, and various mobile operating systems. The ability to manage and switch between multiple processes requires sophisticated memory management and inter-process communication mechanisms within the operating system to ensure stability and data integrity.