Given a computing system with two levels of cache (L1 and L2) and a main memory. The first level (L1) cache access time is 1 nanosecond (ns) and the "hit rate" for L1 cache is $90 \%$ while the processor is accessing the data from L1 cache. Whereas, for the second level (L2) cache, the "hit rate" is $80 \%$ and the "miss penalty" for transferring data from L2 cache to L1 cache is 10 ns . The "miss penalty" for the data to be transferred from main memory to L2 cache is 100 ns . Then the average memory access time in this system in nanoseconds is (rounded off to one decimal place)

Consider a memory system with 1 M bytes of main memory and 16 K bytes of cache memory. Assume that the processor generates 20-bit memory address, and the cache block size is 16 bytes. If the cache uses direct mapping, how many bits will be required to store all the tag values?

[Assume memory is byte addressable, $1 \mathrm{~K}=2^{10}$, $1 \mathrm{M}=2^{20}$]

A computer has a memory hierarchy consisting of two-level cache (L1 and L2) and a main memory. If the processor needs to access data from memory, it first looks into L1 cache. If the data is not found in L1 cache, it goes to L2 cache. If it fails to get the data from L2 cache, it goes to main memory, where the data is definitely available. Hit rates and access times of various memory units are shown in the figure. The average memory access time in nanoseconds (ns) is _________ . (Rounded off to two decimal places)

Consider two set-associative cache memory architectures: WBC, which uses the write back policy, and WTC, which uses the write through policy. Both of them use the LRU (Least Recently Used) block replacement policy. The cache memory is connected to the main memory. Which of the following statements is/are TRUE?