How I/O devices notifies the Operating System
I/O Device Notifying the OS
°The OS needs to know when:
• The I/O device has completed an operation
• The I/O operation has encountered an error
°This can be accomplished in two different ways:
• Polling:
- The I/O device put information in a status register
- The OS periodically check the status register
• I/O Interrupt:
- Whenever an I/O device needs attention from the processor,
it interrupts the processor from what it is currently doing.