Patent GB-788995-A (GB)
Title: Arithmetic unit using magnetic core components
IPC: G11C19/04
Filed: 1954-12-15
Abstract: 788,995. Digital electric calculating-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 15, 1954 [Dec. 18, 1953], No. 36284/54. Class 106 (1). An arithmetic unit for a digital computer comprises a pulse-producing component which completes a number of operative cycles determined by a multiplier cycle control component and applies selected groups of pulses to an accumulator component, each component comprising magnetic cores interlinked by seriesconnected drive windings and having adjacent cores coupled by self-timing capacitor transfer circuits. The multiplying arrangement shown employs magnetic core components, similar to the decimal counter described in Specification 788,994, comprising a ring of ten cores which is stepped on by driving pulses obtained from driving tube (DT) circuits such as 51, Fig. 3. Every time cam-operated switch CR60 is closed, a tube 57 is rendered conductive and a pulse is applied from its cathode, via circuit 51, to pulseproducing counter 50 whose outputs 26-1 to 26-9 are connected as shown through diode matrix 70 to lines 71, 72, 73, 74, whereby during one cycle of counter 50, 1, 2, 4 and 8 pulses respectively appear on these lines. These pulses are applied via gas-filled tubes 75, Fig. 4, to lines 76-79 and accumulator entry relay contact networks (one for each denominational order) whose outputs are connected through contacts of shift relays R84 and relay R63 (energized during accumulator entry) to windings 85 and DT circuits 53 for the accumulators each comprising a group of decimal counters 52 which are selectively connected to circuits 53 through contacts of entry relays R54 (one for each counter group). Carry digits are temporarily stored in cores 86 switched by DT circuits 96 and cleared at the end of an accumulating cycle, whereby " 1 " is added into the next higher denomination by a pulse induced in winding 85, by a pulse from output 26-10, Fig. 3, applied via line 90 and tube 91, Fig. 4, to windings 93. The arrangement is controlled by a punched card 140, Fig. 6, in which numbers represented in binary coded decimal form are sensed column-by-column by brushes 141. An emitter contact 146, stepped in synchronism with the card feed, controls the setting up of the multiplicand digits, on the left of the card shown, on columns of relays R80-1, R80-2, R80-4, R80-8 which control the accumulator entry networks, Fig. 4, whereby a corresponding number of pulses are applied from lines 76-79 to circuits 53. If the multiplicand is negative, relay R82, Fig. 6, will be energized and will shift over contacts in the entry networks to cause a complementary number of pulses to be passed to the accumulator counters. Except for multiplication, the supply of pulses to counter 30, Fig. 3, is stopped after a single cycle, the output pulse on 26-10 being applied via lead 68 to fire tube 62 which then prevents conduction in tube 57. For multiplication by repeated addition, relay R66 is energized and diverts the output 26-10 to D.T. circuit 56 for the multiplier cycle control counter 55 whose outputs 26-1 to 26-9 are connected to a network of contacts of relays 100-1, 100-2, 100-4, 100-8, Fig. 6, which are set up in accordance with the multiplier digits taken in turn from the same or another card, denominational shift in the accumulator being controlled by successive energization of relays R84-n to R84-1. After a number of cycles corresponding to a multiplier digit, an output from 55 is passed by the network to lead 68 to stop further advance of counter 50 as described above. For reading out from a selected accumulator, relay contacts 123, Fig. 4, are closed in turn, whereby 10 pulses obtained from diode mixing circuit 120 are applied to the counters 52. Each carry output pulse on the corresponding lead 24 is applied to lead 127 instead of circuit 96 (relay R63 being de-energized). Such differentially timed pulse causes the conduction of those ones of gas-filled tubes 125-0, 125-1, 125-2, 125-4, 125-8, Fig. 3, which also receive simultaneous pulses through matrix 70 from the output of counter 50, whereby each digit read out is complemented and translated into binary coded form, the conducting tubes producing energization of corresponding relays 130, e.g. for operating a punch or print device as described in Specification 746,724. The magnetic core components may be all reset by energizing relay R109 whereby under control of cam-operated contacts CR104, CR105, the cores are all driven to " 0 " and then the first core is driven to the " 1. " state.