Q. How I-O interface communicate with processor?
The above illustration clearly specifies need communication between processor and I/O interface. This communication includes subsequent steps:
1. Commands like READ SECTOR, WRITE SECTOR, SEEK track number and SCAN record-id sent over control bus.
2. Data which is exchanged between processor and I/O interface sent over data bus.
3. Status: As peripherals are very slow it's important to know the status of the I/O interface. Status signals are BUSY or READY or in an error condition from I/O interface.
4. Address recognition as every word of memory has an address so does every I/O device. So an I/O interface should identify one unique address for every peripheral it controls.