Patent GB-887111-A (GB)
Title: Input system for storage devices
IPC: G06F3/00
Filed: 1958-12-17
Abstract: 887,111. Statistical apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 17, 1958 [Dec. 23 1957], No. 40737/58. Class 106 (1). Data sensed row by row from cards punched in a multiple-bit code is stored in a different multiple-bit code, the data signals for each column being translated to the second code and stored as each bit is sensed, translation of later bits being modified by the presence of earlier bits in the store so that a plurality of bits sensed in the first code are correctly converted into a corresponding representation in the second code. Punched cards passing from hopper 1 under rows of brushes B, B<SP>1</SP> have perforations in 80 columns and 12 rows and are sensed row by row. Brushes B are connected to a matrix m of 80 magnetic cores and brush B<SP>1</SP> to a similar matrix m<SP>1</SP>, the rows being read in turn into the stores. Between rows the data in store m is read out in serial form on line Lm via amplifier Am to trigger Bm. The signals are recoded to a six-bit code in the coder COD and entered into a three dimensional array of cores M having 80 cores in each of seven layers. The code used is shown in Fig. 3, the seventh bit " C " being added as a check to make the number of bits always odd. The punched card code shown in Fig. 2 is translated into the six-bit code during the sensing by considering the data to be read into the store M in relation to what is already in the store, the contents of the store being read out at each cycle. During the sensing of a card cam contacts r1, r2, r4, r8, r0, r<SP>1</SP>0, rA, rB and rC, Fig. 4e, close in a coded sequence, for example as the " 9 " row is sensed, contacts r1, r8 are closed and cores m1 and m8 are switched in store M in any column corresponding to a card column having a " 9 " perforation. In " 8 " position camcontacts r8 and rc close and so on, the contact rc being added so as to make the number of contacts closed always even. The signals from store m appear in succession on line L between row sensings so that corresponding signals pass from the contacts to gating circuits where they are combined with signals sensed previously from the card and stored in store M. These are provided for each column in turn and at each card position, by the triggers Bl, B2, B4, B8, BA, BB and BC. The arrangement is such that as the later perforations in a column arrive the data stored in store M is changed. If a column contains a numeral 8, this will be entered into the store as " one " in the 8 positions, i.e. core. m8 will be set in that column. This value will be read out at each card position and re-entered unchanged. If the " 8 " perforation is part of an alphabetical " Y " a second perforation in the " 0 " position (see Fig. 2) will close contacts r<SP>1</SP>o and ro, Fig. 4e, so that the signal from trigger B8, representing the previously stored " 8," passes through Or gate On to enable And gates eA, e<SP>1</SP>A. Signals are thereby passed through Or gate OA to line LA and through Or gate Ch to And gate e<SP>1</SP>c. The other input to this gate is from trigger BC through an inverter ic and represents " C absent." The output passes via Or gate OC to line LC, recording " C." The signal from trigger B8 also passes through Or gate 08 to line L8. The value stored is therefore changed from " 8 " to " 8, A and C " which represents Y (see Fig. 3). If the symbol represented had been " % " the " 4 " perforation would cause value " 4 " to have been registered with the " 8 " and arrival of an " 0 " signal would add value " A " as before. " C " is suppressed since there are already three digits. Checking.-The number of digits recorded is tested for evenness which would indicate an error. For this purpose each of the lines L1- L8, LA, LB, LC is connected directly and through inverters, Fig. 4d, in three gating networks in which evenness of three separate groups is determined, e.g. 1, 2, 8 and 4, A, B and C with the results of the first two groups. The Or gate Oi gives a signal when the number of digits is odd (i.e. correct). Absence of a signal causes inverter Ii to emit an error signal. The total number of perforations detected on a card by each set of brushes B, B<SP>1</SP> is counted and the two counts are compared in the unit DEN. The counters each consist of four trigger stages C1-C8 and C<SP>1</SP>1-C<SP>1</SP>8, Fig. 4a. One of these counters counts in complementary form, the value being transferred by gates 1E-8E to the other counter. If both counts are equal, the result should be zero, connections to Or gate OE serving to test that at stages C1-C8 register zero. Brush set selection.-Data punched in a certain zone of one card and data punched in another zone of a following card can be simultaneously registered by selecting brush sets B or B<SP>1</SP> by unit SEL, Fig. 1. This consists of And gates ES, E<SP>1</SP>S, Fig. 4c, connecting the triggers Bm and B<SP>1</SP>m alternatively to line L through Or gate OS. Gates ES and E<SP>1</SP>5 are controlled by unit DS an output from which causes data from brushes B to be registered in store M and no output causes brushes B<SP>1</SP> to be effective. The unit DS is controlled by selected timing pulses applied to the input sockets. Comparing adjacent cards.-To determine a change of card group brushes B, B<SP>1</SP> sense successive cards and the values in any number of columns are compared. The values sensed at each row position are read-out of stores m, m<SP>1</SP> column by column and connected together in an " exclusive Or " circuit composed of two AND gates e<SP>1</SP>r, e<SP>11</SP>r, Fig. 4c, and an Or gate. The result appears at terminal S1 and a series of terminals S2, S3 corresponding to the columns being compared may be connected to the output at the appropriate instant to isolate the results for those columns. Specifications 728,272, 741,595, 766,189, 767,760, 853,413, 855,877 and 856,303 are referred to.