medium
2 min read
Page replacement
Page Replacement Definition: Page replacement is a memory management technique used by operating systems to efficiently allocate and manage memory for p...
Quick Actions
Insights
Difficultymedium
Reading Time2 min
Page Replacement Definition: Page replacement is a memory management technique used by operating systems to efficiently allocate and manage memory for p...
Page Replacement
Definition:
Page replacement is a memory management technique used by operating systems to efficiently allocate and manage memory for processes. It involves periodically swapping pages between main memory (RAM) and secondary storage (e.g., hard disk or SSD) to optimize memory usage and system performance.
Process:
Process Mapping: Each process has its own address space, which is divided into fixed-size pages.
Page Table: An operating system maintains a page table that maps process addresses to physical memory addresses.
Swap Space: A separate portion of memory called the swap space is dedicated to storing inactive or partially used pages.
Page Replacement Algorithm: When memory is full, the operating system follows a specific page replacement algorithm (e.g., LRU, FIFO) to determine which page should be replaced.
Swap Out: The selected page is moved from the process address space to the free space in the swap space.
Swap In: When the replaced page becomes active, it is loaded back into the process address space from the swap space.
Benefits of Page Replacement:
Improved Memory Utilization: By swapping out inactive pages, more memory is available for active processes, leading to higher memory utilization.
Reduced Memory Overhead: Pages are loaded and stored only when they are needed, minimizing memory waste.
Faster Program Execution: By eliminating page faults (when the system cannot find a page in memory), program execution is faster.
Example:
Consider a process with 10 pages and 2 pages in memory. When the process uses 12 pages, the operating system would use the LRU algorithm to replace the least recently used page (page 6) with a page from the swap space