Abstract: A computer memory device (10) for storing identified associations between data items of a data collection comprises an array (15) of signal flow pathways (1,2,3 etc) which are respectively rendered representative of data items by an indexing component (12) and input/output circuitry (18) connected to the array (15). Controllable interconnect elements (A,B,C,D,E, etc) selectively interconnect the pathways (1,2,3 etc) in one or more pairs and effect directional control of signal flow between each interconnected pair in accordance with the identified association between the respectively represented data items of the data collection. The interconnect elements (A,B,C etc) are status controlled by signals delivered thereto over respective channels (20A,20B,20C etc) from respective control devices (22A,22B,22C etc) which are contained in a memory (17) which is externally addressable by component (11).