Lehevahetuse

Lehevahetuse, also known as page replacement, is a crucial concept in computer science, particularly in the field of operating systems and virtual memory management. It refers to the process of removing a page from physical memory (RAM) to make space for another page when the system needs to load a new page into memory. This process is essential for managing memory efficiently, especially when the system's physical memory is limited.

Page replacement algorithms determine which page to remove from memory. Common algorithms include First-In-First-Out (FIFO), Least Recently Used (LRU), and Clock. Each algorithm has its own strategy for selecting the page to be replaced, aiming to minimize the number of page faults, which occur when the system needs to access a page that is not in memory.

The performance of a page replacement algorithm can significantly impact system performance. A well-chosen algorithm can reduce the number of page faults, leading to faster execution times and improved overall system efficiency. Conversely, a poorly chosen algorithm can result in frequent page faults, causing the system to spend more time loading pages from disk, which is much slower than accessing them from RAM.

In modern operating systems, page replacement is often managed by the operating system's virtual memory manager, which uses sophisticated algorithms to balance the need for memory space with the need to minimize page faults. The choice of algorithm can be influenced by factors such as the specific workload of the system, the available hardware, and the overall system design.