swapmemory

Swap memory, or swap space, is a portion of a computer's non-volatile storage that an operating system can use as an extension of RAM for virtual memory. When physical memory becomes scarce, the OS moves less frequently used memory pages from main RAM to swap to free up RAM for active processes. This helps prevent memory exhaustion and allows larger workloads, but it comes at the cost of slower access times.

Swap can be implemented as a dedicated partition or as a swap file contained within a filesystem. Linux supports both partitions and files; Windows uses a paging file (pagefile.sys); macOS uses dynamic swap files in a dedicated area. The choice affects performance and management; some systems prefer a fixed partition, others a flexible file.

Performance considerations: Accessing data in swap is substantially slower than RAM, so heavy swapping can degrade responsiveness. Systems under heavy memory pressure may thrash, moving data back and forth frequently. Using solid-state drives reduces latency, and some platforms implement memory compression or tools to reduce swap usage. Increasing physical RAM or adjusting memory configurations can improve performance.

Management and monitoring: Administrators can enable or disable swap, create partitions or files, and adjust parameters that affect when and how aggressively the system swapps. In Linux, for example, swappiness is a tunable parameter. Monitoring tools include free or top in Linux, Task Manager in Windows, and Activity Monitor in macOS. Modern operating systems manage swap automatically; manual tuning is often unnecessary except in specialized workloads.

See also: virtual memory, paging, memory management.