Which of the following best describes 'cycle stealing' in a DMA operation?
2025
Which of the following best describes 'cycle stealing' in a DMA operation?
- A.
DMA controller locks the system bus until the full block is transferred.
- B.
DMA controller accesses the bus only during memory refresh cycles.
- C.
DMA controller and CPU share the bus in a round-robin fashion.
- D.
DMA controller takes control of the bus for a single cycle, suspending CPU access briefly.
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Correct answer: D
In DMA (Direct Memory Access) operation, cycle stealing refers to a technique where the DMA controller temporarily takes control of the system bus for a single bus cycle to transfer data. During this brief period, the CPU is paused from accessing the bus. After the transfer, control is returned to the CPU.
This method allows both the CPU and DMA controller to operate efficiently without completely blocking the CPU for long periods.