1. A memory system for a digital data processor, said memory system comprising: (a) input network means for merging signals representing components of command packets and store packets, said signals representing components of command packets and store packets consisting of signals representing transactions to be performed by said memory system; (b) output network means for distributing signals representing components of retrieval packets, said signals representing components of retrieval packets consisting of signals representing the results of transactions specified in said signals representing components of command packets on said memory system; (c) a plurality of sub-memory system means for holding a plurality of records representing certain of said components, said records designated by unique identifiers; (d) distribution network means for transmitting signals representing components of said command packets and of said store packets from said input network means to members of said sub-memory system means in correspondence with the signals representing components of said command packets and said store packets, said signals representing components of said command packets and said store packets containing signals representing said unique identifiers associated with said records contained in said sub-memory system means; (e) arbitration network means for transmitting signals representing components of said retrieval packets from said sub-memory system means to said output network means; (f) said signals representing components of store packets specifying data items sent to said memory system by some external device to be stored in said sub-memory system means and associated with one of one of said unique identifiers; (g) said signals representing components of retrieval packets specifying data items retrieved from said sub-memory system means and sent to some external device; (h) said signals representing components of command packets specifying whether a store operation or retrieval operation is to be performed on said records in order to generate and control said signals representing components of said store packets and said signals representing components of said retrieval packets, said store operation representing the storage of a data item in said memory system and said retrieval operation representing the retrieval of a previously stored data item from said memory system; and (i) each of said sub-memory system means consisting of storage means for storing data in response to signals received from said distribution network means and representing command packets specifying store operations and signals received from said distribution network means and representing store packets containing data items, retrieval means for retrieving data items from said sub-memory system means in response to signals received from said distribution network means and representing command packets specifying retrieval operations, said data items retrieved from said sub-memory system means transmitted as signals representing retrieval packets to said arbitration network means.