Siirtosivut

Siirtosivut is a Finnish term that translates to "transfer pages" or "move pages." In the context of computing and digital systems, it refers to a mechanism used in memory management, particularly in operating systems, to handle situations where data or code needs to be moved between different locations in memory. This concept is closely related to virtual memory systems.

When a program requires data or instructions that are not currently in the main random-access memory (RAM), the operating system must fetch them from secondary storage, such as a hard drive or SSD. This process often involves moving other, less actively used data out of RAM to make space for the required information. These pages being moved are called siirtosivut.

The operating system maintains a page table to keep track of which pages are in RAM and which are on secondary storage. When a page fault occurs, indicating that the requested page is not in RAM, the system identifies a suitable siirtosivu to replace. This replacement page is written back to secondary storage if it has been modified, and the new, requested page is then loaded into RAM.

The efficiency of siirtosivut management significantly impacts system performance. Algorithms are employed to determine which pages are the best candidates for replacement, aiming to minimize the number of page faults and the time spent on these transfer operations. Common algorithms include Least Recently Used (LRU) and First-In, First-Out (FIFO).