dma cycle and burst mode

Question

hard disk with transfer rate of 1 KBps is constantly transferring data to memory using DMA. The size of data transfer is 16 bytes. The processor runs at 400 kHz clock frequency. The DMA controller requires 10 cycles for initialization of operation and transfer takes 2 cycles to transfer one byte of data from device to the memory. Let M and N be the maximum percentage of time that the CPU is blocked in cycle stealing mode and Burst mode. Find the value of M-N?

a)2.26          b)3.45        c)2.35       d)2.35    

My solution plz verify if not correct plz give detailed explanation

Comments

the value 16 used in  calculating the transfer time(y) is the value of X or is it the number of bytes of data mentioned in the question

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Could anyone please clearify why   2 cycle time transfer time (between device and memory) is being considered while computing CPU consumption time

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Can anybody please tell me, why did we not use y/(y+x) in cycle stealing mode?

Answer 1

u didnt followed pipilining at the side of cycle stealing mode for one byte it will take 12 cycle and for remaining it will take only 10 cycle bcz while transfering the data  , preperation of data is suppose to happen parraleli .