Patent GB-779030-A (GB)
Title: Data comparator
IPC: G06F17/15
Filed: 1955-03-25
Abstract: 779,030. Statistical apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. March 25, 1955 [March 29, 1954], No. 8739/55. Class 106 (1). A comparing device for comparing a primary multi-order data group with a secondary multiorder data group comprises means to compare corresponding orders so as to detect order positions having matched and those having unmatched data and means for indicating that the data groups are matched when the comparing means detect identity or predetermined conditions of mismatching between the orders compared. The comparator is described embodied in a record card controlled collator as described in Specification 523,652. In this machine primary cards from a stack are fed along one path, past sensing brushes, towards a series of pockets, Secondary cards are fed from another stack along another path, past sensing brushes towards the same series of pockets. Primary and secondary cards are directed into the same pockets according as to whether or not they are matched. It is often convenient also to pass as matched, cards whose data differs in certain specified ways one from the other. These ways are shown in Figs. 3, 4, 5 and 6 and are designated respectively " crosscompare," i.e. in position 4 a direct comparison detects an unmatched condition; " transposition of orders," Fig. 4, i.e. the orders of the secondary data in positions 3 and 4, have been transposed; " right-offset ", Fig. 5, i.e. owing to a misspelling the letters of positions 4, 5 and 6 in the secondary data are offset to the right with reference to the primary data in positions 3, 4, 5; and " left-offset ", Fig. 6, i.e. for a similar cause the secondary data in positions 3, 4, 5 is offset to the left with reference to the primary data in positions 4, 5, 6. The device described below passes all these groups of data as matched. Comparator code relays.-Line 66, Fig. 10a, is connected through the brushes sensing the primary cards to plugs 70, 71 which are connected by jacks to code relay units 75 ... 80. Similarly secondary card sensing brushes are connected to the relay units 81 ... 86. By these connections each position 1-6 on the card is associated with primary and secondary code relay units. The units 75 and 81 are shown diagrammatically and the others are similar. Each unit, e.g. 75, comprises four relay pick-up coils P, the relays being numbered R1, R2, R3, R4 in primary unit 75, R5, R6, R7, R8 in secondary unit 81 and the remainder as shown, The pick-up coils are connected to the jack plugs through diodes on one side and, on the other, through cam-controlled contacts C1, C2, C3, C4 to the opposite line 67. As shown in Fig. 8, the data is arranged in nine rows and the cams rotate in synchronism with movement of the cards past the reading brushes. The nine rows therefore correspond to nine index times. The code relays in each unit are conditioned for energization in accordance with a code, a different set of relays being conditioned for each index time. The relays conditioned are picked by coincidently timed signals from the sensing brushes. The hold coils for the primary and secondary relays are arranged in similar groups, Fig. 10b (not shown), and are connected between the lines 66, 67 through cam-controlled primary and secondary contacts which operate only when the corresponding card feed is in operation. By this arrangement those relays which are picked-up during one machine cycle will remain picked up for the number of cycles that the corresponding card feed is stopped. Compare circuits.-As shown in Fig. 10c the relay contacts are arranged in groups in series with check relays R9-R24. The circuits are divided into three categories :-those including relays R9-R14 for making a direct comparison between primary and secondary data in each position; those including relays R15-R19 for comparing data in each primary position with that in the secondary position offset one place to the right and those including R20-R24 for comparing data in each primary position with that in the secondary position offset one place to the left. Cross-compare category.-In this category the contacts of primary code relay unit 75-80 are interconnected with the contacts of secondary code relay units 81 ... 86 so that the readings of the primary brushes in position 1 are directly compared with the readings of the secondary brushes, that is contacts of relays R1 and R5, R2 and R6, R3 and R7 and R4 and R8 are connected in pairs so that if neither or both of these relays is picked, the circuit is established through the coil of relay R9, but if one only is picked (the corresponding primary and secondary brush readings being different) the circuit is broken and relay R9 is not picked. Relays R10-R14 likewise depend on the comparison of the readings of primary and secondary brushes in positions 2-6. In the case of a pair of unmatched data groups, as shown in Fig. 3, the different data in position 4 will be detected so that relay R12 is not picked while the others do. Data groups differing in one position only may be passed as matched by the circuit of Fig. 11. In the example described, the circuit from line 101 is established through contacts R9-1 normally open (n/o), R10-1 n/o, R11-1 n/o, R12-1 normally closed (n/c) and R14-2 n/o to plugs 115, 116. These plugs may be connected by jacks to " equal output " line 102. Where the data groups are matched in all positions a circuit is established along the top line of contacts between line 101 to plugs 117, 118 which are connected by jacks to line 102 to pass matched cards. Where the data groups differ in one position only the circuit is along the top line to the contacts corresponding to the differing position (R12-1 in the example described) and then along the second line to plugs 115, 116. Where it is desired to pass such groups as matched these plugs are connected to the line 102 as described above. The top line contacts are connected to the contacts of the second line so that if any relay has not picked up, it is bypassed by transfer to the lower line. Where the data groups differ in more than one position the circuit is transferred, by the same process, to the third line, i.e. the line including contacts of " right-offset " category relays R15-R19. " Right-offset " category.-The relay contacts are connected in this category so that the primary brush readings of each position is compared with the secondary brush reading in the adjacent position to the right. The circuit of check relay R15, for instance, includes contacts associated with pairs of relays R1 and R29, R2 and R30, R3 and R31 and R4 and R32. Where there are similar brush readings in the adjacent positions at the same index time, therefore, these pairs of relays are both picked or both not picked and a circuit is established through the coil of a check relay, R15. Where they are different, no circuit is made and the corresponding relay is not picked. The contacts of these relays form the third line in the circuit of Fig. 11. Where data groups are unmatched in more than one position the circuit from line 101 is brought down to this third line of contacts. In the case of Fig. 5, for example, the data groups are matched in the first three positions so that the " cross-compare check relays R9,. R10, R11 are picked up. Also the primary positions 3, 4, 5 are matched with the secondary positions 4, 5, 6 and so the " right-offset " check relays R17, R18, R19 pick. Thus in Fig. 11 a circuit is established from line 101 through contacts R9-1 n/o, R10-1 n/o, R11-1 n/o, R12-1 n/c, R13-2 n/c,R18-1n/o, plugs 113, 114 and jacks to equal output line 102. If this jack connection is made, therefore, such unmatched data groups will be passed as matched. " Left-offset category.-The third group of check relays R20-R24 are connected in circuits consisting of contacts belonging to pairs of relays, the secondary relay of each pair being associated with a position offset one place to the left relative to the position associated with the corresponding primary relay. In the circuit of check relay R20, for example, relays of primary code unit R25-R28, corresponding to position 2, are matched in pairs with code relays R5-R8 of secondary unit 81 corresponding to position 1. If the data in these offset positions are similar the corresponding check relays R20-R24 are picked. Thus in the case of the dissimilar data groups shown in Fig. 6, the first three positions are matched so "cross-compare" " check relays R9, R10, R11 are picked. Further, since the data in primary positions 4, 5, 6 is matched with that in secondary positions 3, 4, 5, " leftoffset check relays R22, R23, R24 pick. Thus in the circuit of Fig. 11 a circuit is established from line 101 through contacts R9-1 n/o, R10-1 n/o, R11-1 n/o, R12-1 n/c, R13-2 n/c, R18-1 n/c, R22-1 n/o, R23-1 n/o, R24-1 n/o to line 111, 112. If jack connections are made to equal output line 102 these dissimilar data groups are passed as matched. The circuit of Fig. 11 only passes a left-offset dissimilarity when it is due to the omission of a symbol (G) which is one of a plurality of adjacent like symbols. Another circuit is given (Fig. 12, not shown) designed to pass " left-offset " dissimilarities arising, for instance, from the omission of any symbol from the secondary data group. Transposition of orders.-In a case such as shown in Fig. 4 where the symbols in two positions of the secondary group are transposed with respect to the primary symbols in those positions. Since the data in positions 1, 2, 5 and 6 are similar " cross-compare " check relays R9, R10, R13, R14 will pick. Further since the data of primary position 3 is the same as that of secondary position 4, " right-offset " check relay R17 will pick. Also since the data of primary position 4 is the same as that of secondary position 3, " left-offset " check relay R22 will pick. A circuit from line 101, Fig. 11, will, therefore, be es