Patent GB-806873-A (GB)
Title: Improvements in or relating to electrical apparatus for storing data sensed from record cards
Inventor: BIRD RAYMOND
IPC: G11C11/28
Filed: 1955-04-12
Abstract: 806,873. Electric digital-data-storage apparatus. BRITISH TABULATING MACHINE CO. Ltd. April 12, 1955, No. 10456/55. Class 106 (1). Electrical apparatus for storing data sensed from record cards comprises a plurality of gasfilled binary storage tubes, means adapted to establish a glow discharge to a first electrode of each of the tubes prior to the entry of data therein, means adapted to sense a column of a record card, a coding commutator operable in synchronism with the card sensing means, and connections from the sensing means and the commutator to a second electrode of each of the tubes adapted to cause transfer of the discharge to the second electrode of one or more of the tubes, such that the location of the discharge in the tubes represent the sensed data in accordance with a pre-determined code, the discharge being established between a third electrode or electrodes and either the first or second electrodes. Each storage tube 1, 2, 3, 4 is so arranged that both sides cannot conduct simultaneously and is such that the discharge can be transferred from one side to the other either by applying a positive pulse (240 v. relative to cathode) to a central transfer electrode or by applying a negative pulse to the cathode of the non-conducting side. Each tube normally has 280 v. applied to the anodes from a line 5 via a normally conducting diode 40, and 110 v. applied to each cathode, from a line 7 via a resistor 8 for the right-hand cathodes and from the line 7 via resistors 23 and 17 for the left-hand cathode. The left-hand cathode is also connected via a diode 11 to a brush of a coding commutator 14 which is such that normally line 7 is connected to the diode 11. Thus the voltage of the left-hand cathode is prevented from falling below 110 v. except when the associated brush on the commutator 14 contacts an insulating segment. In these circumstances a tube is said to be primed. The commutator 14 is arranged to prime combinations of tubes 1, 2, 3, 4 representative (on an excess three code) of the value of the indexed position of a record card column being sensed by a brush 21. Initially each tube is caused to conduct on its right-hand side (this being the " cleared " condition) by closing a contact 10, and then when a hole is sensed every left-hand cathode is connected to earth via contacts 22 but only those tubes which are primed have their state changed. The apparatus is then storing the value that was registered in the sensed column. Read-out is effected by closing contacts 29 and 42, opening contacts 16, 22 and 41 and causing a read-out commutator 28, which is driven synchronously with the card feed mechanism, to successively apply a negative pulse to the left-hand cathode of each tube 1, 2, 3, 4. In synchronism with the successive pulsing of the storage tubes cam-controlled contacts 31 apply positive pulses to the grid of a gas-filled triode 24 which is so arranged that with contacts 41 and 42 open and closed, respectively, the voltage at the lower end of a resistor 6, which then forms the anode load for the storage tubes, maintains the triode cut off. Each positive pulse would, by itself, cause the triode to conduct, giving an output pulse on a lead 33, but any positive pulse that coincides with the pulsing of a storage tube conducting on its left-hand side is cancelled by the negative pulse that appears across resistor 6. This triode 24 only fires to give an output pulse when a storage tube conducting on its right-hand side is being sensed by the read-out commutator. Camcontrolled contacts 25 open between each pulse to extinguish the triode if it has fired. The state of each storage tube can be inverted by applying a positive pulse to each transfer electrode via a lead 34. An extra storage tube 35 could be used for alphabetical data. The apparatus could be adapted for row sensing instead of column sensing. Specification 692,322 is referred to.