DMA Doubt

Question

can someone explain what is preparation time in DMA exactly?

and why is it multiplied by CPU cycle time in most of the questions here?

does preparation time means that a word is brought into disk controller buffer from hard disk and it utilizes CPU?

PS-DMA is giving me headaches!!!

Comments

https://gateoverflow.in/132309/dma-cycle-stealing?show=274476#a274476

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I'm not getting the numerical.... I want a simple answer to what is meant by data preparation time? and what is the difference b/w data preparation time and transfer time