DmA

Question

Answer 1

In 1s CPU makes 300 million ticks, so time for a tick (clock time) is 1/(300 * 10⁶ )  = 3.3 ns.  

For 900 cycles, CPU time will be 900*3.3 = 2970 ns = 2.97µs 


Now, time for data transfer = 200/5000s = 40ms = 40000 µs 

So, percentage of CPU time for transfer =  2.97/(40000+ 2.97) = 0.0074%

Comments

In 1s CPU makes 300 million ticks, so time for a tick (clock time) is 1/(300 * 10⁶ )  = 3.3 ns. 

For 900 cycles, CPU time will be 900*3.3 = 2970 ns = 2.97µs


Now, time for data transfer = 200/5000s = 40ms = 40000 µs

So, percentage of CPU time for transfer =  2.97/(40000+ 2.97) = 0.0074%

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Thanks for clearing

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sir since hard disk is directly sending data to memory doesn't it mean it is burst mode?

if so then cpu overhead will be 100%.