1. A data retrieval system for use with a data processing system, the system comprising: a first memory; a second memory accessible to said first memory; a data file residing in said second memory, said data file containing stored data organized into nests; a data structure residing in said first memory, said data structure designed to occupy a fixed amount of memory independent of content of said data file, said data structure organized according to hash values produced by a hash function for retrieving items in said data file, the hash values having associated offset values for accessing a nest of said data file; and a data retrieval module in communication with said first memory, said data retrieval module operable to instantiate the hash function, to calculate a hash value based on input data, and to make an identification regarding a corresponding nest of the data file via said data structure, the identification based on the associated offset value of the hash value, wherein the hash function is based at least in part on parameters selected according to characteristics of the data file, wherein the hash function is further designed to be optimized for content of said data file, and wherein the hash function is further designed to produce hash values based on the fixed amount of memory.