GATEverse — GATE CSE previous year questions

A computer system has a three-level memory hierarchy, with access time and hit ratios as shown below:

\overset{ \text {Level $1$ (Cache memory)} \\ \text{Access time = $50 nsec/byte$}}{\begin{array}{|l|l|} \hline \textbf{Size} & \textbf{Hit ratio} \\\hline \text{$8 M $ bytes} & \text{$0.80$} \\\hline \text{$16 M $ bytes} & \text{$0.90$} \\\hline \text{$64 M $ bytes} & \text{$0.95$} \\\hline \end{array}} \quad \overset{\text {Level $2$ (Main memory)} \\ \text{Access time = $200 nsec/byte$}}{\begin{array}{|l|l|l|} \hline \textbf{Size} & \textbf{Hit ratio} \\\hline \text{$4 M$ bytes} & \text{$0.98$} \\\hline \text{$16 M$ bytes} & \text{$0.99$} \\\hline \text{$64 M$ bytes} & \text{$0.995$} \\\hline \end{array}} \quad \overset{ \text {Level $3$} \\ \text{Access time = $5$} \mu \text{sec/byte}}{\begin{array}{|l|l|l|} \hline \textbf{Size} & \textbf{Hit ratio} \\\hline \text{$260M$ bytes} & \text{$1.0$} \\\hline\end{array}}