Question

In which of the following cache mapping may contain replacement-bits in cache tag directory entry for each block in cache?
I. Direct mapping
II. Set-associative mapping
III. Fully-associative mapping

• A. I, II and III
• B. I & II only
• C. II & III only
• D. II only

Answer 1

The correct option is C II & III only

option (c)

In direct mapping there is no any choice for block replacement available, because there is only one block at each mapped index. In set-associative and fully associative mapping at each mapped index, there are multiple blocks present. So among those multiple blocks which block is to be replaced for this replacement-bits may be stored to implement any replacement policy.