용어

active object== Task

passive object == information hiding object == Object (task에서 컨트롤하는 스레드 안에서 실행됨)

Task Structuring

I/O task structuring criteria

asynchronous I/O device interface task

• task for each asynchronous I/O device
• interrupt를 발생시킴

Periodic I/O device interface task

• task for each polled I/O device
• interrupt를 받음
• samples I/O device (샘플링은 장치의 현재 상태나 값을 읽어오는 행위)

Passive I/O device interface task

• task for each passive I/O device
• does not need to be polled
• passive input device는 more likely to be polled
• 계산 작업과 동시에 출력 작업이 실행됨

Internal task structuring criteria

periodic task