Question

Question 9 Which of the following statements is true about memory system? Put the answer in the box. A. Cache memories are usually built by SRAMs, which have higher density and faster access speed than DRAM-based main memories. B. Secondary storages such as hard disk drive and solid-state drive are typically volatile memories. C. Compared to the associative cache mapping function, direct mapping function has more flexibility. D. Due to locality of reference, the basic transfer unit between cache and main memory is block (a set of data with contiguous addresses). Question 10 Consider a memory system with a 8-block cache memory and a larger main memory. Assume the cache is initially empty. If the processor accesses main memory blocks B2, B15, B16, and B26 (block number starts from B0) repeatedly three times, answer the questions below. 1) If a direct-mapped cache is used, what will be the cache hit rate? Put the answer in the box. A. 25% B. 33.3% C. 50% D. 66.7% 2) If a 4-way set associative cache and the LRU replacement policy is used, what will be the cache hit rate? A. 25% B. 33.3% C. 50% D. 66.7%

Answer 1

Ans @ "A"- explaination - According to definition of Cache memory, It is an intermediate form of storage between the registery and the RAM! Considering the main requirement for Cache is speed, they are built of a portion of memory made of high speed static RAM (SRAM) instead of slower and cheapes dynamic Ram (DRAM) used for main memory. and having higher density. Therefore, option "A" is correct option 0 An "B" - explaination! First let me tell you about volatic. volatile memory care is one which do require Power to remember the data and which donot require Poury to maintain/ remember the data known as non-volatis. Therefore, Hard disk drives are magnetic Storage derices capable of remembering a vast amount of data without requirement of Power & And solid state drive uses semiconductor chips not magnetic media to store data and they can remember data with and no requirement of Power. Therefore, Hard disk drive and solid state drive are non-volatic. -C)" In fully associative mapping , A block of main memory Can be mapped to any freely availab6 Cache line. This makes associative mapping more flexible than direct mapping. Therefore option "c" is incorrect ♡ Locality of reference is the tendency of the Computer to access instructions whose

addresses are near one another In case of focality of reference, when CPU wants to read of fetch the data of instruction. first it will access the Cache memory as it is near to it and provides very fast access. If the required data is found it will be fetched. If required instruction is not found in the Cache memory then main memory will be searched for the required data l instruction that was being searched. Therefore, from the above explaination we can say that due to locality of reference, the basic transfer unit between cache and main memory is not blocked. And so option &" is wrong.