What is the function of data input command in I/O command?
2021
What is the function of data input command in I/O command?
- A.
Activate the peripheral and to inform it what to do
- B.
To check status conditions in the interface and the peripheral
- C.
It cause the interface to respond by transferring data from bus into one of its registers
- D.
It cause the interface to respond by transferring data from one of its register to bus
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Correct answer: D
Key point: The data input command causes the device/interface to place data from one of its internal registers onto the system bus so the CPU can read it.
डेटा इनपुट कमांड का सारः डिवाइस अपने किसी रजिस्टर से डेटा बस पर रखता है ताकि CPU उस डेटा को पढ़ सके।
Data flow for input: device register → system bus → CPU register.
Contrast with output: an output/write operation moves data from the bus into a device register (bus → device register).
Other command types such as activating the peripheral or checking status are control/status operations, not data input operations.
Therefore, the correct description of the data input command is: it causes the interface to transfer data from one of its registers to the bus so the CPU can read it.