What is an Associative memory? What are its advantages and disadvantages?

An associative memory is also called content addressable memory (CAM). A word is found by its content, not by an address. The search key is compared with all stored words at the same time, and the matching word is returned.

Advantages: the search is very fast, because all words are checked in parallel, and no address is needed. It is useful for cache tags and page tables.

Disadvantages: every cell needs its own comparison logic, so it is costly, takes more space, and is built only in small sizes.