A compromise between a direct mapped cache and a fully associative cache where each address is mapped to a certain set of cache locations. The address space is divided into blocks of 2^m bytes (the cache line size), discarding the bottom m address bits. An “n-way set associative” cache with S sets has n cache locations in each set. Block b is mapped to set “b mod S” and may be stored in any of the n locations in that set with its upper address bits as a tag. To determine whether block b is in the cache, set “b mod S” is searched associatively for the tag.
A direct mapped cache could be described as “one-way set associative”, i.e. one location in each set whereas a fully associative cache is N-way associative (where N is the total number of blocks in the cache). Performance studies have shown that it is generally more effective to increase the number of entries rather than associativity and that 2- to 16-way set associative caches perform almost as well as fully associative caches at little extra cost over direct mapping.
- Set at
Also, set upon. Attack or assail, as in The dog set at the postman, or The hyenas set upon the wounded lion. The first term dates from the early 1400s, the variant from the late 1300s.
- Set at rest
see: lay at rest
noun 1. a dog trained to assist a person with a disability that is not related to vision or hearing.
- Service discovery protocol
protocol (SDP) A Bluetooth protocol in the Core Protocol Stack that allows devices to connect to other services. Bluetooth SDP (http://bluetooth.org/assigned-numbers/sdp.htm). (2002-06-28)