Patent GB-827194-A (GB)
Title: Improvements in business machines
Filed: 1956-05-22
Abstract: 827,194. Comparing record cards. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 22, 1956 [May 23, 1955], No. 15732/56. Class 106 (1). A statistical machine comprises means for feeding punched cards successively through a single sensing station and means for comparing data on one card at the sensing station with data carried by a preceding card including a matrix of magnetic core storage devices and means for reading out of the matrix the data from the preceding card, storing it in a bi-stable device and immediately afterwards reading in to the matrix the data from the said one card, thereby producing a further output signal from the matrix, means being provided to compare this second signal with the first signal in store to obtain comparison indications. As shown in Fig. 9, cards are fed in succession under sensing brushes 23, the card 20 being that previously sensed and card 21 being the card present under the brushes. A cam 35 closes a contact 37 when the card is properly positioned in the sensing station and the card also operates a lever to close contacts 38. A circuit through these contacts initiates the sensing operation. The read-in and read-out operations are controlled by pulses shown in Fig. 8. There are eighty columns of bi-stable magnetic cores 25 forming the memory device, these corresponding to the eighty columns of the record card. Each core is coupled by a winding with a separate brush 23 and a pulse generator 34 operated by PBP pulses reads data sensed into the cores. A circuit represented by block 27 successively energizes the conductors 28, 29, 30, &c. to readout the data column by column, the circuit being controlled by an " A " pulse PAP, Fig. 8, to erase the record in the cores of all or desired ones of the columns. Both the read-in and readout operations cause a signal to appear on a horizontal lead 31, 32, &c. associated with any core whose state is changed. Where a hole is punched in the same position in successive cards the corresponding core is driven from the initial state to the alternative state during the sensing of the first card, the erasure of the memory by the read-out pulse " A " passes a first signal to circuit 33 and the change of state of the core by the read-in " B " pulse during reading of the second card passes a second signal to the circuit 33, which compares it with the first signal. The read-out and read-in circuits 27, 34 are controlled by a distributer arrangement consisting of two counting rings of bi-stable latch circuits, each of which comprises a cathode follower supplied through a gate and a double inverter. The output from the cathode follower provides one input to the gate so that it stays positive as long as the other gate input is positive. A chain of ten latches (for units) is stepped by control pulses NAP and the chain of eight latches (for tens) is stepped when the " 0 " latch of the units ring is activated. The output terminals are successively driven positive, as shown in Fig. 8, lines 7-10, and are connectable as described below to read-out the eighty columns of the core memory and read-in data from the following card. Where only a few columns are to be compared an open chain of latches may be provided connectable to the desired column of the core matrix by plug connections. As shown in Fig. 16 the output terminal 71 is connected to And gates 82 and 83. These gates are connected to the grids of valves 81L and 81R. Where a brush 23 senses a hole, the state of the core corresponding to that hole will be changed as previously described. The positive output on terminal 71 extends for a period, including a positive " A " pulse and a positive " B " pulse. These pulses are applied to gates 82, 83, the former causing valve 81L to conduct and apply a negative read-out pulse to all cores of this column. Any core set is returned to zero and gives an output on the horizontal wires of Fig. 9. A positive " B " pulse following the " A " pulse passes through gate 83 and causes valve 81R to conduct and apply a small positive magnetization to the cores of the column. That core corresponding to the brush sensing a hole is additionally magnetized by the brush winding and is accordingly driven to the other state to read-in the new data and an output again appears on the horizontal wires. These two signals are of opposite polarity. The signals on the horizontal wires are received in the circuit shown in Fig. 17. Each horizontal row has a lead such as 85 leading to transformer 86, the secondaries of which are connected through diodes to produce a positive pulse irrespective of the polarity of the pulse on the wire 85. The read-out signal at " A " time is inverted in inverter 92 to provide a negative pulse on line 93 and gated in double triode 94L, 94R with the negative " A " pulse (Fig. 8). The output which is normally positive passes to the upper input of gate 96. The double inverter 97 and cathode follower 98 constitute a flip-flop set by an input on line 85 and reset by positive " C " pulses PCP at the end of each cycle. The output on conductor 99 is normally positive but goes negative when a value is read out corresponding to the value of lead 85 (say " 0 "). The read-in signal from the next card occurs at " B " time and if it is the same value it appears on lead 85 to be gated in a similar manner with the negative " B " pulse in double triode 95L-95R. The output is a negative pulse on normally positive lead 100. The leads 99 and 100 are gated together by diodes 104, 105, output on lead 106 indicating coincidence, i.e. identical values on present and previous cards. The leads 101, 102 correspond to the next row lead 103 (i.e. value " 1 "), the signals on these being gated together as before to produce an identity signal on lead 113. Also each read-out lead 99, 101 is gated with the read-in lead 100, 102 for every other column position. A signal on lead 109 indicates that the value on the present card is higher than that on the previous card; lead 112 indicates that it has a lower value. Where the record cards have ten numeral spaces there would be one hundred junctions, as shown in Fig. 18. Each junction shown as a solid black dot is connected to a low indication network, a square shows it is connected to an equal indication network and an open circle shows it is connected to a high indication network. All the junctions normally high are connected through Or gates to give a signal when any one is down and similar circuits are provided for the equal junctions and the low junctions. This gives an indication that the value of the read-in pulse is higher than, equal to, or lower than the value of the read-out pulse. By this means it is shown whether the data on the preceding card is higher in value, equal to, or lower in value than the data on the card under the sensing brushes. Specifications 693,143 and 710,554, [Group XL (c)], are referred to.