Improvements in or relating to an associative memory

摘要

988,765. Data storage apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. April 16, 1963 [April 17, 1962], No. 14734/63. Heading G4C. The impedance of a large parallel cryotron associative memory is increased and the switching time reduced by dividing the memory into blocks to shorten the length of parallel paths, the blocks being searched and read-out serially. When a match has been found the flip-flop MI associated with a word is set (current in righthand limb). A "begin read" pulse sends current from source +T to the limb V. If at least one MI flip-flop in Block 1 is set, current from source +Z sends cryotron 3 resistive and the current from +T sends cryotron 4 resistive. Current from +R is thus steered to interrogate the flip-flop MI. If a flip-flop is off, a cryotron such as cryotron 6 is resistive, otherwise the +R current is used to read-out the matched word. During read-out a control flip-flop is set. After a predetermined time line G is pulsed which causes the set control flip-flop to switch off the MI flip-flop e.g. current from source 0 passes through gate 14 to send gate 109 resistive. A pulse on line H then steers current from source +S to switch off the control flip-flop. The current from source +T is thus steered by the switched-off MI flip-flop to interrogate the next MI flip-flop and possibly initiate a similar read-out process. When all the MI flip-flops of Block 1 are switched off, current from +Z flows through gate 2 and is available to initiate interrogation of Block 2.