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A swap file, also referred to as a memory page, is used by a program or, more often, the operating system as temporary swap space to store the contents of virtual memory on a storage drive when not enough physical memory is available.[1]


A swap file is usually allocated as a contiguous block of a drive space to reduce access time. In the meantime, the drive space used for a swap file can not be used for other purposes.[2] Swap file performance was once considered slow due to the latency of reading and writing to a hard drive, but has improved with the adoption of solid-state drives (SSDs). However, some users have expressed concern that swap file activity would reduce the life expectancy of SSDs.[3]


In 1990, Adobe Photoshop became one of the first programs to introduce the use of a swap file (called "scratch disk"), when Apple Computer's own System 6 had not yet implemented virtual memory.[4] Under Microsoft Windows, swap files are recommended not to exceed three times the available RAM and are usually 150 percent of the RAM size.[2]


  1. Swap space at the Free On-Line Dictionary Of Computing. 1994-11-03.
  2. 2.0 2.1 Swap file at the Free On-Line Dictionary Of Computing. 1996-11-15.
  3. Why are swap partitions discouraged on SSD drives, are they harmful? by Takkat, Ask Ubuntu, StackExchange. 2015-07-24.
  4. PhotoShop Version History, MiniCreo. Accessed 2021-12-09.

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