When modified working storage pages need to be paged out (moved from memory to the disk), they are written to paging space.
当需要将经过修改的工作存储分页替换出(从内存移动到磁盘)时，它们将被写入到分页空间。
2
If the page is modified, the page replacement daemon writes the page out to a secondary storage location (for example, paging space or file system disk).
If you do this and the external storage is not available on a reboot, your system might crash (depending upon the amount of space allocated to paging).