Which one of the following facilitates transfer of bulk data from hard disk to…
2022
Which one of the following facilitates transfer of bulk data from hard disk to main memory with the highest throughput?
Answer: A. DMA based I/O transfer — Key idea: DMA allows the device controller or a DMA controller to transfer blocks of data directly between the disk and main memory without the CPU copying…
- A.
DMA based I/O transfer
- B.
Interrupt driven I/O transfer
- C.
Polling based I/O transfer
- D.
Programmed I/O transfer
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Correct answer: A
Key idea: DMA allows the device controller or a DMA controller to transfer blocks of data directly between the disk and main memory without the CPU copying each word.
DMA advantages: supports block/burst transfers and bus-mastering, minimizes CPU intervention, and therefore achieves the highest throughput for bulk data movement.
Interrupt driven I/O: reduces busy-waiting but still generates frequent interrupts the CPU must service, adding overhead compared with DMA.
Polling and Programmed I/O: polling wastes CPU cycles checking device status; programmed I/O has the CPU copy each word. Both approaches involve much more CPU work and have lower throughput for bulk transfers.
Conclusion: DMA based I/O transfer provides the highest throughput for transferring bulk data from hard disk to main memory.
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