Fuente: Wipo "digitalization" 784,496. Digital electric calculating-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Feb. 2, 1954 [Feb. 5, 1953], No. 3070/54. Class 106 (1). [Also in Group XL (c)] In a device for adding digits represented by electrical input pulses timed to have numerical significance, comprising input storage devices each adapted to store a pulse having a particular numerical significance, the pulses are routed to the storage devices selectively by two groups of devices for entering true and complementary values respectively, and coincidence switches each responsive to output voltages from a particular group of storage devices selectively operate devices to manifest the sum of the digits. General arrangement. The computing arrangement described comprises a magnetic drum MD, Fig. 1, having " computer " tracks 11 and distributer tracks 12 associated with circuits 10 and 13. These circuits are controlled by timing pulses obtained from tracks 16 and circuits 14 (not described in detail) and by an operation selector 15, e.g. an automatic programme control unit or manually operable keys or switches. The circuits 13 may be connected to a general store which may be a further portion of the magnetic drum but, as particularly described, comprises manually settable data-input switches and a neon lamp output register. The tracks 11, 12 (A and B), Fig. 9, each have spaced reading and recording heads associated therewith whereby information is continually read, erased and replaced by the same or new information. The tracks 12A, 12B form an intermediate store between the input/output arrangements and the " computer regeneration " and " computer operation " tracks 11A, 11B. The latter have their normal reading and recording heads coupled through regeneration and arithmetic circuits to form " revolvers." Values are normally stored in the regeneration revolver except when a computation or other operation is taking place, and are transferred to this revolver at the end of an operation. As well as the four rules and left and right shifts, the operations which may be selected include a round-off (" half correction ") and right shift, and a test for all zeros in a stored computer value (" balance test "). Number representation; timing pulses. Numbers are represented in coded-decimal serial form on the drum tracks 11 and 12, Figs. 1 and 9, and associated circuits, each digit being represented by two magnetic spots, or corresponding timed pulses, in one of the quinary positions or cells QO-Q4, Figs. 3 and 38, and one of the binary positions or cells BO-B5. The eighth cell O provides a space between digits. The distributer tracks 12A, 12B, Fig. 9, comprise groups of 11 digit positions DG1-DG11 for storing a 10-digit decimal number plus a sign (9 for " + ", 8 for " - ") as indicated, while the computer tracks 11A, 11B can store either two separate 10-digit numbers or a 20-digit number in positions DG2-L to DC11-L (" lower computer ") and DG1-U to DG10-U (" upper computer "), the positions DG1-L and DG11-U normally containing zero. The signs of computer numbers are dealt with separately in the associated circuits. As indicated in Fig. 43, each cell contains a " A " point at the beginning and a " B " point in the middle, these points being defined by corresponding timed positive and negative A and B pulses. The number-representing signals (e.g. the zero signal, Fig. 43) obtained from the drum reading circuits comprise A pulses, while the signals employed in the computing circuits (e.g. QO AA) comprise mainly A-to-A pulses (see bottom of Figs. 38 and 43). Some timing signals, however, extend from B to B (e.g. QO BB). As well as the signals in Fig. 38, further signals are employed for defining the digit periods DG1-DG11 and the upper and lower computer periods (Fig. 39, not shown). Distributer. The main distributer track 12A, Fig. 9, forms with reading and recording heads 35, 36 and a regeneration circuit 37 a revolver for continually storing one factor in a co