Which of the following statements about programmed I/O mode of data transfer…
2022
Which of the following statements about programmed I/O mode of data transfer between CPU and I/O devices is correct?
- A.
The programmed I/O mode of data transfer is faster than interrupt mode of data transfer.
- B.
In this mode, there is wastage of the CPU cycles.
- C.
In this mode, the CPU can do other works when I/O devices are not ready for data transfer.
- D.
In this mode, the data transfer is initiated by the interrupt signal issued to the CPU.
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Correct answer: B
In programmed I/O, the CPU repeatedly checks the I/O device status. This polling keeps the CPU occupied while waiting, so CPU cycles are wasted. Hence, option B is correct.