Virtual memory provides more efficient use of memory and lessens the likelihood that low memory conditions will cause an abend.

Available memory is assessed to see which data has been used less recently than the rest. How recently data has been used is determined by a bit in each field of the translation table that indicates whether the address translation has been used since the last time it was checked. Data that has not been used for some time can be moved from memory to disk, thus freeing memory for other uses.

When the data on disk is needed again, it is moved back into available memory. Because data is swapped in and out of disk, the available memory can be used for a larger amount of data than its actual physical capacity would allow.

The Java Virtual Machine and any modules that are loaded into protected address spaces use virtual memory. Both the modules and the data they access are subject to being swapped to disk.

Server operating system modules do not use virtual memory, because they cannot be swapped to disk.

The memory management subsystem assesses the memory needs of all server and NLM processes and determines where the freed memory should be used. The subsystem stores freed memory in disk cache.

When data is moved from memory to disk, it is stored in a swap file. You can create one swap file for each NetWare volume. A swap file is created for the Sys volume by default.