Assoziativer Duennschichtspeicher

摘要

1,151,466. Associative stores. INTERNATIONAL BUSINESS MACHINES CORP. 29 Nov., 1967 [7 Dec., 1966 (2)], No. 54251/67. Heading G4C. [Also in Division H3] An associative store has two cells per bit, each cell having two magnetically-coupled anisotropic magnetic films. In the associative store of Fig. 4, each bit is stored in both true and complement form in respective storage cells, e.g. A1 (true) and A11 (complement). Each cell has two anisotropic magnetic films separated by a layer of insulator, viz. a high coercivity " storage " film and a low coercivity " read " film. The magnetic vector in the storage film lies in one sense or the other (depending on the bit stored) along the easy axis and biases the read film so that its magnetic vector, M in Fig. 4, lies antiparallel along the hard axis of the read film, the easy axes of the two films being orthogonal. Any cell storing 1 has the storage film only partially switched so that the read film is barely saturated in one sense to store 1 but is well into saturation in the other sense to store 0. During associative interrogation, bit drivers 26, 261 pulse bit lines 24, 241 positively and negatively respectively to interrogate for 1 or negatively and positively respectively to interrogate for 0. Any mismatch produces a pulse in one of detection lines 20, 201 depending on the sense of the mismatch, a match detector 22 ORing the detection lines 20, 201. The array of cells is staggered as shown for noise reduction. A word may be non- destructively read out by pulsing both lines 20, 201 with the same polarity at low amplitude, a sense pulse being produced on one of the two bit lines 24, 241 in each case, the two bit lines being combined in a differential sense amplifier 28. To write in a word, the word is cleared by pulsing both lines 20, 201 (or other lines not shown) at high amplitude, then the new word is written by coincident-current technique pulsing lines 20, 201 and (with data-dependent polarities) bit lines 24, 241. Fig. 7 shows one cell of the associative store of Fig. 10. A high coercivity " storage " magnetic film 10 and a low coercivity " read " film 12 with easy axes EA1, EA2 interact as before but are separated by a bit line 14, the ends of which are connected to a bit driver 18 directly and via a conducting ground plane 16 respectively. 20 is a match detection line, 24 is a word write line, 28 is a magnetic keeper and 18 is insulator. In the store of Fig. 10, each bit is stored twice, e.g. in cells A1 and A11. Each bit position, e.g. A1, A11, to be associatively interrogated is pulsed positively on line 14 to interrogate for 1 or negatively on line 141 to interrogate for 0, a pulse being induced on line 20 in the ease of mismatch. A word can be read out on the lines 14 non-destructively in pulse/ no-pulse form by pulsing line 20. Coincident current write-in is possible using lines 24, 14, 141.