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