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Consider a DRAM that must be given a refresh cycle 64 times per msec. Each refresh operation require 100 nsec and a memory cycle require 200 nsec. The percentage of the memory’s total operating time must be given to refresh is ________. (Upto 2 decimal places)

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here once we access memory then in these 200 ns(as given memory access time) the refreshing will be performed along with data access(read or write ) not both simultaneously.

in 1ms we are refreshing 64 times

in 200nsc we will refresh = 12.8 times

1 refresh operation takes 100ns

=> 12.8 refresh operation will take =12.8*100ns-(1)

among 200 ns that we are using for memory access above time is refreshment overhead

so % of memory access time used is= )(1)/200ns) *100=0.64

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