I/O priority and interrupt

Features used to divert program attention to new input data, the completion of output buffer transfers, or emergency conditions (inquiries, errors) existing on peripherals. The interrupt feature relieves need for much program checking of status of units.; 迫使程序中止轉去處理新的輸入數據,完成輸出緩沖區的傳送或者處理外圍設備中發生 的緊急情況(如查詢、出錯等)的能力。中斷的特性使得程序不必花費大量時間頻繁查詢 檢查外圍設備的狀態。