Patent GB-703593-A (GB)
Title: Apparatus for magnetically recording and storing data
IPC: G11B5/76
Filed: 1952-04-07
Abstract: 703,593. Digital electric calculating apparatus. NATIONAL CASH REGISTER CO. April 7, 1952 [April 11, 1951], No. 8800/52. Class 106 (1) Apparatus for magnetically storing data and reading and recording stored data comprises a storage element on different portions of which different items of data are recorded in the form of discrete magnetic spots, reading means associated with the storage element which, when the storage element is moved, transmits signals corresponding to the magnetic spots to a data-retaining register, recording means associated with the storage element and adapted to receive signals from the register corresponding to the data retained in the register, and routing means operable in timed relation with the movement of the storage element to cause the data from the storage element to be entered correctly in the register and to enable the data retained in the register to be recorded in correct location on the storage element. In the described embodiment the storage means comprises a rotatable cylinder 15, Fig. 2, grooved to receive wire loops 23 of magnetic material spaced longitudinally along the cylinder and each having capacity for storing an eight-figure decimal amount in sections a ... h, Fig. 15B. A reading and recording head 46 and an erasing head 47 are mounted in a support 49 which can be moved into co-operative relation with any of the storage elements 23. For convenience the magnetic wire may be a continuous length anchored at both ends and crossing over from one groove to the next at a longitudinal slot in the cylinder. In each denomination sector a ... h of a record loop a number of spots are magnetically recorded according to the values of the respective digits of a number, and upon selection of such a record and tripping of a clutch to cause the cylinder to be driven from a constantly rotating shaft, the groups of spots pass under the head 46 and cause pulses on a line 242 which is connected via a switch CS-2, rotating at half the speed of the cylinder 15, to the input terminal 241a of an amplifier and shaping circuit comprising tubes 244, 265 and 286, Fig. 15A. The output of this circuit passes via wire 300 to a secondary rotary switch RS-1 which directs each group of pulses to the entry device E.a.b. &c. of the appropriate order of an electronic accumulator of the type described in Specification 658,370. Thus each accumulator order is stepped on by an amount equal to the appropriate recorded digit. The accumulator may or may not contain an amount prior to the read-in operation and, in the former case therefore, the amount from the record is added to that standing in the accumulator ; if the prior amount is entered in complementary form, subtraction is performed. Immediately after each digit pulse group has been reproduced by the head 46, the record is erased by a head 47, but when the cylinder completes the first revolution the erasing head energizing circuit is broken as the half-speed switch arm CS-1 moves onto contact 6. During the second revolution of the cylinder 15 the amount standing in the electronic accumulator is recorded digit by digit on the selected wire loop. The digits are "rolled out" in descending order by groups of ten pulses each derived from a magnetic loop 29 on the cylinder having a read-out head 45 which now becomes connected through the rotary switch CS-2 to the input terminal 241a of the amplifier and pulse shaping circuit 244 &c. and feeds ten pulses to each denomination of the accumulator in descending order. In each order, as the discharge reaches the "O" tube, an impulse from the cathode of the latter fires a gas-filled control tube 120 now rendered operable by the completion of its anode supply circuit by a relay 3R operated through a rotary switch CS-4. The firing of each tube 120 causes a positive bias on the suppressor grid of an associated hard valve 121 which, acting as a gate, passes the pulses subsequently applied to its control grid via a capacitor 215. The pulses from its anode pass via a wire 310a to the appropriate contact of a rotary switch RS-2 and from the wiper arm to an output impulse amplifier comprising tubes 311, 325 and 340. From the cathode of the last tube the pulses pass via terminal 348a (see also Fig. 15B) and rotary switch CS-3 to the head 46 which is now used to record the digits on the selected magnetic wire loop. The manual entry means comprises switches SW3a ... h which, when set to the required number, apply bias to the cathodes of the appropriate tubes of the accumulator. Further switches SW-2 determine' whether the true number or its complement is entered. Neons 190 indicate the amount standing in the accumulator.