virtual memory
Virtual memory is an OS feature that operates as a memory substitute for the hard disc. Moreover, more memory space can be secured through use of this feature than simply using actual memory. Virtual memory uses a dedicated area of the hard disc known as the "swap file" to temporarily shelter inactive memory parts, to be called forth at need. The interchange of swap file contents is known as a swap. If little memory space remains, the OS must frequently carry out swaps, and this negatively affects performance.