If the virtual cache buffer contents are not all resident in memory, then the copy process will trigger a page fault, which generates a second re-entrant I/O operation via the paging mechanism.

• 如果虚拟高速缓存的缓冲区内容并非全部都是常驻内存的，那么复制进程将触发一个页面错误，这将通过页面调度机制产生一个再次重入I/O操作。