GB873367A - Improvements in or relating to information storage devices - Google Patents

Abstract

873,367. Pulse storage apparatus. INTERNATIONAL COMPUTERS & TABULATORS Ltd. April 22, 1958 [May 31, 1957], No. 17350/57. Class 40 (9). [Also in Group XIX] The storage device shown in Fig. 2 comprises a magnetostrictive wire 1 supported between damping blocks 2. The wire material is such that its hysteresis characteristic changes under mechanical stress from X-Y, Fig. 1, to a more rectangular form E-F. A pulse is initially applied to winding 3 of such amplitude as to saturate the wire to point X so that it is in a uniform remanent magnetic state corresponding to point A. An 8-bit word is written by applying a serial train of " 1 "-representing pulses to winding 3 while a stress wave is propagated along the wire, each pulse being of amplitude corresponding to point P whereby the remanent state of the wire is left substantially unchanged (point A(1)) in the unstressed portion but is reversed (point C) in the stressed portion. The stress wave is launched by applying a pulse to coil 5, or alternatively by a piezo-electric crystal, and passes successively through points P(1)-P(8) which are thus selectively magnetized to represent the word. The word may be read out by applying a further pulse to coil 5, the passage of the resultant stress wave along the wire causing a pulse to be induced in winding 3 for each point at which a " 1 " is stored. In a multiple storage device (Fig. 3, not shown), a stress-wave producing coil similar to 5 is common to a set of storage wires contained in parallel channels of a supporting block. The information stored in the different wires may be interleaved. The wires may be replaced by ribbons or tubes, and each coil such as 3 may be replaced by individual coils, one for each digit storage position. In a further modification, a word is written on to the storage wire 1 by applying a pulse train to coil 5, and a single pulse to winding 3. The wire may be pre-stressed so as to obtain the rectangular hysteresis characteristic, the stress waves obtained through coil 5, representing the complement of the information to be stored, changing the characteristic back to the original form. Alternatively, pre-stressing may be employed effectively to increase the difference between the two hysteresis characteristics. Specification 698,061 is referred to. Reference has been directed by the Comptroller to Specification 780,005.