Made Easy Test Series

Question

Consider the following statements:

S1 : Direct mapped caches do not need a cache block replacement policy, whereas fully associative cache need.

S2 : Direct mapped cache, may produce more misses if programs refers to memory words that occupy a same tag value.

Which of the following options is correct?

Answer 1

Option A True – In direct mapped cache a mapping algorithm is used to map the block in specific cache location. Hence no cache block replacement policy is needed . Replacement policies are used in Associative Caching and Set Associative Caching. 

Option B False - In direct mapped cache misses generally conflict miss occurs and that too because of two different blocks mapping to same Cache line (same cache line offset ) .There is no affect on misses with tag bits being same or same tag value.

Comments

hit only occure for a perticular line if tag bit and line bit are same and miss only occure if atleast one of  tag bit or line bit is different  correct it

Answer 2

@LRU

Option A ,  true ...

S1:: Direct mapped caches do not need a cache block replacement policy, where as fully associative cache need....

Option B , false ...

S2:: Direct mapped cache, may produce more misses if programs refers to memory words that occupy a same tag value...

 

1. https://gateoverflow.in/285714/Madeeasy-test-series-co-%26-architecture-cache-memory

 

Answer 3

Carl Hamacher fifth edition.