Which of the following mapping is not used for mapping process in cache memory ?

Concept: Cache memory uses one of three block-placement (mapping) schemes to decide where a main-memory block is stored in the cache: direct mapping, associative (fully-associative) mapping, and set-associative mapping. Address translation for virtual memory, by contrast, uses schemes such as paging, segmentation, or a combined segmented-page scheme -- these belong to main-memory management, not to cache block placement.

Application: Three of the four options name genuine cache mapping schemes; the fourth names a virtual-memory address-translation scheme. Direct mapping, associative mapping, and set-associative mapping are all recognised techniques for placing a memory block into the cache. Segmented-page mapping translates a virtual address to a physical main-memory address -- it governs main-memory addressing, not cache-block placement, so it is the one not used for cache mapping.

• Associative mapping: any incoming block can be placed in any cache line; all tags are searched in parallel to check for a hit, giving the lowest conflict-miss rate at the highest hardware cost.

• Direct mapping: each memory block maps to exactly one cache line, computed as (block address) mod (number of lines); simplest hardware, but the highest conflict-miss rate.

• Set-Associative mapping: cache lines are grouped into sets; a block maps to one specific set but may occupy any line within that set -- a middle ground between the two schemes above.

• Segmented-page mapping: combines segmentation and paging to translate a virtual address into a physical main-memory address; it is a memory-management technique, not a cache-block placement scheme.

Answer: Segmented - page mapping is not used for the cache mapping process.