An interrupt in the execution of a program caused by its referencing a page or segment that is not in primary storage. Following the VSI, system routines locate the required page/segment in secondary storage, locate a place for it in primary storage, read it into primary storage, and adjust table entries to indicate its new location. When a VSI occurs, instruction execution is commonly passed to another program.; 程序運行時的一種中斷，由于訪問不在主存中的一個頁或段所引起。在VS I之后，系統(tǒng)例行程序在輔存中找到所需頁段，并為其在主存中找到適當?shù)目臻g，將所需頁 段讀進主存，然后修改表項以指出它的新地址。當VSI發(fā)生時，通常將指令執(zhí)行轉到另一個 程序。參閱discard， thrashing。