Memory Hierarchy Q.64

0. A main memory unit with a capacity 4 megabytes is built using 1M × 1-bit DRAM chips. Each DRAM chip has 1K rows of cells with 1K cells in each row. The time taken for a single refresh operation is 100 nanoseconds. The time required to perform one refresh operation on all the cells in the memory unit is

Answer
Comment
Array

Option : D
Explanation : Main memory unit has capacity = 4 MB
Number of DRAM chips = 4MB/ 1M*1bit = 32
1 DRAM chip has 1 K (2¹⁰) rows and 1 K(2¹⁰) cells
In each row = 32 * 2¹⁰ * 2¹⁰ = 32 * 2²⁰
Time taken in one refresh opn
= 100 ns
Time required to perform one refresh operation on all the cells in MM unit
= 32 * 2²⁰ * 100 = 3200 * 2²⁰ ns

Forgot your password?

I agree with the Terms.