Patent GB-824227-A (GB)
Title: Improvements relating to the storage of signals
Filed: 1956-03-09
Abstract: 824,227. Electric digital-data-storage apparatus. DIRKS, G. June 6, 1957 [March 9, 1956], No. 7372/56. Class 106 (1). Apparatus for selectively reading and/or recording. data under control of a movable member which may occupy any one of a plurality of discrete positions, includes settable switching means prearranged to correlate the positions of the movable member with storage addresses in a cyclically moving storage member and controlling sensing and/or recording means to read and/or record data in selected storage areas. As described, the movable member is a typewriter carriage 7, Fig. 2, with a flexible arm 6 in frictional contact with a stationary member 14. At each step movement of the carriage the arm 6 is dragged to one side or the other, according to the direction of carriage movement, and makes electrical contact with one of two rigid arms 4 and 5 before returning to its central position. The electrical pulses so produced are fed via pulse-shaping devices 12, 13, Fig. 1, and amplifiers 22, 23 to a decade counting tube 19, adapted to count both positively and negatively and with carry-over to a further decade tube 25. Thus, the count registered in these tubes represents the position of the typewriter carriage at any time. By means of a decoding matrix 26 the count is interpreted by the energization of one of a hundred output lines 27/1 . . . 27/100 leading to plugboard switching panels 29 and 30 which associate the carriage positions with storage addresses. The panel 30 interprets the marked line 27/1 ... 27/100 in terms of the track required on the drum 1 and the signal representing this track effects, through a device 33, a mechanical movement of the pick-up head 35 to the track required. The panel 29 is used to interpret the section of track to be selected, and this data is applied to a comparing device 47. The other input to the comparing device is from a counting tube 45 which counts the number of data-wordmarking pulses 42/1 ... 42/n on track 40 of the drum occurring after the detection of a datum pulse 43. The transmission of this latter pulse is preferably delayed to allow time for the mechanical movement of the head 35 to be completed. When the count of pulses 42/1 ... 42/n agrees with the value on lines 31/1 . . . 31/n a gate 49 is opened to allow the selected data-word to be read by the head 35 and set up in a further counting tube 52. The setting of this tube is subsequently transmitted via lines 53/1 ... 53/n to an output device 54 such as a printer or punch. A similar arrangement may be employed for writing data on to the drum at an address determined by the position of the movable member. Mechanical movement of the head 35 may be performed by a linkage as shown in Fig. 5a in which a commutator disc 101 fixed to a crank 99 is rotated by an electric motor until that one of the contacts 103/1 . . . 103/n which is connected to the marked line 32/1 ... 32/n comes opposite an insulator segment 104, thus opening the circuit of the driving motor. Comparing device.-Each input line 31/1 ... 31/n, Fig. 6, from the switching panel 29 is connected via a resistor 115/1 ... 115/n to a point at which the equivalent line 46/1 ... 46/n from the counter 45 is connected, via a resistor 116/1 ... 116/n, and also a further resistor or a diode 117/1 . . . 117/n connects to a common output line 48. A significant output signal on the latter only occurs when the input signal pattern on lines 31/1 ... 31/n agrees with the pattern on lines 46/1 ... 46n. In another arrangement (Fig. 7, not shown) gas-filled valves are used instead of the elements 117/1 ... 117/n. Other suggested modifications include detection of carriage movement by photo-cells co-operating with a scale bearing alternate clear and opaque portions, or by magnetic heads sensing relatively moving magnetic teeth. Chains of bi-stable trigger circuits may be used instead of multi-cathode counting tubes. Instead of moving the head 35 from track to track, a plurality of heads, one for each track, may be provided, together with a suitable selective switching arrangement. Specifications 786,021, 786,033 and 786,034 are referred to.