Patent GB-869252-A (GB)
Title: Checking device for record processing machines
IPC: G06F11/10
Filed: 1959-09-25
Abstract: 869,252. Verifying record cards. OLIVETTI & CIE S.p.A. ING. C. Sept. 25, 1959 [Oct. 4, 1958], No. 32734/59. Class 106 (1). A record is verified during the recording process by deriving for each column a check bit which indicates whether the number of marks in that column are odd or even, storing this check bit in a two-state comparing store, sensing the record to derive for each column a number of signals equal to the number of marks in the column, feeding these signals to the check bit store through means which alters the state of the store for each mark sensed so that in effect " 1 " is subtracted for an odd number and " 0 " for an even number and operating an alarm circuit if after this process the store is not returned to its original condition. The apparatus is applied to a tape to card converter, blocks of eighty columns being read off the tape, recoded in block 3 to a twelve-position record card code and stored in a three-dimensional core store 5 having twelve arrays of eighty cores. Each column is represented by the corresponding cores in each of the twelve arrays. A read-out circuit, 10, 27, presents the stored data to a comparator 38 which through gates 46 controls the operation of the punch selector magnets in punch 11. This operation is controlled by a selector circuit 8 governed by a counter 43 fed with pulses from generator 24. The counter when started by a signal from the punch 11, counts up to eighty and returns to zero. The selector selects in turn the cores of each array of eighty cores so that the twelve output leads are energized according to the data marks to be entered into successive columns. These outputs are briefly stored on flip-flops 27 to provide inputs 55 to the code comparator 38, which is in effect a series of twelve gates. The punch has a punch coder 47 which selects the row positions in turn by energizing the appropriate lead 48 to open the corresponding gate in the comparator 38. The twelve rows are thereby gated out in turn, and the marks in the eighty successive columns appear in succession on lead 56, there being 960 signals in all. The eighty gates 46 are also enabled in succession and the signals on lead 56 are entered row-by-row into the 960 punch selecting magnets. The signals on lead 56 are also entered into check-bit generator 13. This consists of an array of eighty cores 14 each able to store a " 1 " or an " 0." There is one core for each column. As the signals enter on lead 56 the cores are read out in turn by circuit 8, the outputs being stored briefly on flip-flop 25 which controls gates 36 and 37 so that a " 1 " enters on lead 58 and is written into a core when a mark signal appears from the corresponding column in store 5. The second mark for that column will return the core to " 0 " since gate 36 will not be open and the inverted signal will pass to line 58. The check bit generator therefore constitutes a scale of two counter. The operation of the punch is cyclic. It provides eighteen timing pulses per cycle, twelve of these are used for entering the twelve rows of the card into the punch and the remaining six for punching, reset operations and feeding the cards to the next positions. As the store 14 is reset, the eighty.check bits stored are transferred via gate 41 and entered into store 21 of the comparator 20. In the next cycle as the following card is in the punch station, the first card is being sensed at 17. A series of eighty brushes sense the card row-by-row and the brushes are pulsed in turn by circuit 8. The card is fed between rows by the row signal from the punch 11. For each row the column signals appear successively on line 19 and the cores in store 21 are read-out so that flip-flop 26 is set or reset according to the check bit entered for the column currently under the energized brush 18. Gates 32, 33 are controlled so that where the core reads out a " 1 " and no signal is entered on line 19 the " 1 " is re-entered on line 60. Where the read-out is " 1 " and a " 1 " appears on line 19, " 0 " is entered. The comparator in effect subtracts in a scale of two, the marks in each column from the check bit stored in core array 21. If for each column the number of marks agrees with the number entered in the check bit generator, the store 21 should be completely clear at the end of the twelve reading steps. This is then tested by resetting all the cores, any core set causing a signal to pass through gate 42 to a device 62 which signals an error.