The default implementation provides access to the basic retrieval functionality, as well as exposes the parameters defined in 4.0 (LatencyFactor,LatencyExponent) and permits partial matching (if the declarative module's PartialMatchingEnabled is true).
Since it can be so useful for those that aren't completely concerned with retrieval behavior, the module also permits the use of indexed retrievals. If you already have a reference to a specific chunk (say as a slot value), you can insert it directly into the retrieval buffer to access it on the next cycle. To enable this, set the EnableIndexedRetrievals to true. Otherwise, +retrieval> =chunkRef will merely create a pattern based on that chunk and search for it, as is the canonical behavior.
Unlike most other buffers, the retrieval buffer provided by this module does not copy the chunk on insertion. It won't permit you to make modifications (=retrieval> slot newValue) will always fail. This was done to prevent unnecessary copying. Reference counts/access times are still consistent.
Actual retrievals are merely delegated to the declarative module. If the declarative module is asynchronous, so too shall the retrievals.
The module now supports parameter overrides when specifying a retrieval. These overrides hold for the duration of that single retrieval only. See below for options.

Parameters

• RetrievalThreshold : default 0. -Infinity to disable entirely. If -Infinity is used, 0 will be used for the retrieval time equation so that failed retrievals don't take infinite time to complete.
• LatencyFactor : default 1.
• LatencyExponent: default 1. (unpublished parameter).
• EnableIndexedRetrievals : default false. If true, a direct reference to the chunk is immediately retrieved.
• FINSTDurationTime: default 3 seconds.
• NumberOfFINSTs: default 4 chunks.

Meta-slots

• :recently-retrieved : Test for whether this chunk has been recently retrieved (values: true/false). Can be used at request (RHS) or matching (LHS).
• :retrievalThreshold : Temporarily use the specified retrieval threshold (any number, NaN, (-)Infinity)
• :partialMatch : Temporarily enabled/disable partial matching (true/false)
• :indexedRetrieval : Temporarily enabled/disable indexed retrievals (true/false)
• :accessibility : determine which activation value to use for the retrievability of a chunk ("summation", "base level", "spread", "max", "min", default : "summation")
• :retrievalTime : determine which activation value to use for retrieval time calc (same as :accessibility)