Patent GB-813743-A (GB)
Title: Improvements in or relating to data storage apparatus
Inventor: BIRD RAYMOND
IPC: G11C11/28
Filed: 1955-08-30
Abstract: 813,743. Electric digital-data-storage apparatus. BRITISH TABULATING MACHINE CO. Ltd. Aug. 30, 1955, No. 24838/55. Class 106 (1). A data-storage element comprises a gas-filled diode, Fig. 2, one electrode of which is connected over a lead 34 and a load impedance to a voltage source, and the other electrode of which is connected (a) to two control lines 21, 22 over a resistor 39 and two oppositely connected unidirectional conducting devices, the voltages of the control lines normally being such as to lock the voltage of the second electrode so as to maintain the gas-filled diode in its conducting or non-conducting state, (b) to a lead 27 by which an input signal may be applied to cause the diode to fire or extinguish when the voltages applied to the control lines 21, 22 have been modified to unlock the second electrode, and (c) to a read-out line 31 by which may be applied a pulse of short duration in relation to the deionisation time of the diode so as to produce an output pulse across the load impedance if the diode is conducting. The voltages on the control lines 21, 22 are normally the same but to unlock the second electrode, one is raised and the other lowered. A number of elements, 1, 2, 3 ... , Fig. 1, may be arranged in a matrix-as shown, one of three words each having four bits. The control lines 21, 22 and 31 are common to the elements of a word and the input and output leads 27, 34 of equivalued bits in the several words are connected to amplifiers 13-16 and associated triggers 17-20, used for both input and output. An amplifier and associated trigger are shown in Fig. 3. To enter a bit, the trigger is set so as to conduct in its right-hand section (1) or in its left-hand section (0). The left-hand anode is connected via the amplifier triode 44 to the lead 27 which thus assumes the required low or high potential so as to cause any unlocked storage diodes connected thereto to fire or extinguish respectively. The read-out pulse applied to the lead 31, Fig. 1, is negative and consequently, a negative pulse appears on the output lead 34 connected to a conducting (1) diode. This is inverted by a pulse transformer 42, amplified and inverted by the triode 44, and applied to the left-hand grid of the trigger so as to cause the right-hand section to conduct. The passage of negative pulses from the triode 44 to the left-hand grid of the trigger is normally prevented by a diode 50, the anode of which is held over a lead 53 at a higher potential than the grid, but to permit read-out the potential of lead 53 is lowered. Parallel read-out from the triggers may be effected by re-setting them and taking pulses from the left-hand anodes or by means of gates conditioned by the triggers. Stepping register.-The triggers 17-20 may be interconnected to form a stepping register so as to permit serial entry and read-out. For this purpose, the anodes of each trigger are connected through respective gate circuits to the corresponding grids of the succeeding trigger. Each gate, Fig. 5, is formed by a double triode, negative shift pulses being applied to the righthand grid, and the left-hand grid and anode being connected respectively to the anode of the one trigger and to the grid of the succeeding trigger. The right-hand section of the gate is normally held conducting but on the application of a negative shift pulse, the left-hand section will conduct if the anode of the one trigger is at a high potential and a negative pulse will be applied to the grid of the succeeding trigger so that the corresponding section will assume the same state (non-conducting) as that section of the preceding trigger.