Patent GB-719850-A (GB)
Title: Improvements in or relating to electrical calculating apparatus
IPC: G06F7/498
Filed: 1952-11-19
Abstract: 719,850. Digital electric calculating-apparatus. INTERNATIONAL BUSINESSS MACHINES CORPORATION. Nov. 19, 1952 [Nov. 23, 1951], No. 29208/52, Class 106 (1) A calculating machine comprises two sets of code relays, an electronic circuit for entering a factor in each of the relays, a "greater than," "less than," and " equal to " comparing circuits including contacts of the relays for determining the relative magnitudes of the factors, an electronic circuit controlled by the " greater than " and " equal to " circuits for initiating the summation of the factors and a circuit controlled by the "less than" circuits for shifting one of the factors, the relays being energized in combination to respresent the various factors. The calculating apparatus described is of the relay accumulator type in which three sets of code relays are provided, these sets function as augend addend and sum relays where one set is permanently utilized as the addend. means and the other two alternately operate as augend and sum means. The amount set up in the augend and addend are added and entered into the sum relays which is then transferred back to the augend. The factors from a record card, Fig. la, representing the multiplicand and multiplier or the divisor and dividend as the case may be, may be entered into the corresponding one of five accumulating orders or positions of any of the four factor receiving devices namely augend, addend relay storage and capacitor storage, while readout operations may be made only from the augend or relay storage device. The record card is moved past sensing brushes in the usual manner with the conductive roll 17 coupled through cam controlled contacts C16, Fig. 1a, to the line 14 coupled to the 40 volt positive power supply. The factors on the record card are represented in decimal form and are converted to a coding notation 0, 1, 3, 5, through the energization of translating relays, Fig. 1d. There is provided a separate set of translating relays for the augend and addend factor receiving devices while there is a common set of translating relays for the relay storage and capacitor storage receiving devices. The translating relays for the augend are R279, R280, R319 and R320, Fig. 1d, respectively representing the values 0, 1, 3, 5. The translating relays for the addend are R247, R249, R287 and R289, Fig. 1d, and the translating relays for the relay storage and capacitor storage receiving devices are R646, R648, R649, and R651, Fig. 1d. The energization of the translating relays is controlled by the translating cams C45, C47, C48 and C49, Fig. 1d, these four cams are so timed as to cause the energization of the particular translating relays concerned thereby enabling the equivalent values for each index point from 0 to 9 to be registered in code, so that as the respective sensing brushes traverse the index point positions of the record card the translating cams in synchronism with the feeding of the record card then cause the energization of the translating relays representative of the va!ue equivalent to the index point being sensed. For example, when the " 8 " in the factor 83 represented in the card shown in Fig. 1a is sensed and which is to be entered in the second order of the relay storage receiving device, the translating relays R651 and R649, Fig. 1d, representative of the code values 5 and 3 will be in an energized state and the associated contacts R649c and R651c, Fig 1a, in the translating network will be closed, then a complete circuit can be traced from the conductor 14, Fig. 1a, cam controlled contacts C16, brush 16, roll 17, brush 10, entry control relay contacts R669g now closed respective contacts R649c and R651c, corresponding contacts R653k and R653z, respective relays R638, R639 and then to ground thereby causing relays R638 and R639 to be energized. A hold circuit for these relays through the associated " a " contacts will be set up through the alternative making and breaking of the cam controlled contacts C11 and C14, Fig. 1a. A similar arrangement is made for entering a value directly from the record card into the augend direct. After the values have been sensed, converted and entered in the proper factor receiving relays the programme counter, Fig. 1e, becomes effective. Programming.-The programme counter provides ten programme steps for selecting and ordering the operations to be performed, depending on the plug connection to the hubs of the control relays R122, R121, R161, respectively for multiplication, division and addition. The programme counter is rendered effective at the end of a card reading cycle when the cam controlled contacts C37, Fig. 1e, make at 9.4 index time, enabling the programme start relay R621 to be energized. The programme counter is a decimal relay counter which is advanced through the ten programme steps by the count relay R622, Fig. 1e, which is pulsed by the gate relay or the calculator complete relay R203, Fig. 1e, at the end of the operation called for by each programme step. Comparison circuit.-The function of the comparison circuit is to compare the factors registered in the augend and addend for the purpose of controlling multipiication or division operations. The circuit is arranged to compare the true va'ue registered in the addend with the value registered in complementary form in the augend in order to determine if the latter value is equal to, smaller than, or larger than the former value. If the results indicate when the augend is either equal or greater than the addend, then an " ON " pulse will be emitted from the comparison circuit as an adding pulse. If the comparison of the two values indicate that the addend is greater than the augend then the " ON " pulse will be applied in the form of a shift pulse to the column shift readout circuits. The comparison starts with the highest order and continues through the second order to the third order.. In multiplication the multiplier is registered in the augend in form and reduced by repeated subtraction of the digit 1 entered in the first order of the addend. The " ON " pulses are continuously applied to the comparison circuit for the purpose of controlling subsequent multiplication or divisional operations, if the comparison indicates that the angend is either equal to or greater than the addend then the " ON pu'se will be emitted from the comparison circuit as an adding pulse, if the comparison indicates that the augend is less than the addend then the " ON " pulse will be emitted as a shift pulse. The shift pulse is applied over conductor 70 through the augend readout circuit for each order of the augend for the purpose of shifting each respective order to the next high order. The shift pulse will also be applied to the product-quotient counter over conductor 71, Fig. 1j for the purpose of registering each shifting operation. Adding circuit. adding circuit for each order of the augend includes contacts of the augend and addend relays construction and arranged as a biquinary circuit with instantaneous carry, i.e. the values 0 and 5 are registered on a binary circuit while the remaining digits are expressed as a quinary digit having the values 0, 1, 2, 3, 4. The two binary and the two quinary digits are added separately, when the quinary sum is greater than four a plus 5 is carried into the binary circuits, when the binary sum is then a plus I is carried into the quinary circuit of the adjacent higher position. The binary add and carry circuits are separate networks including intercoupled contacts associated with the A5 and B5 code relays. The binary carry network is so arranged as to read out a no-carry signal if the binary sum is zero and a carry signal if the sum is ten. The adding impu!se is applied over conductor 99 to the binary carry circuit, Fig. 1n, the no-carry and the carry signals are applied to the adding circuit of the next higher order over the respective conductors 100, 158. If the binary sum is five, the binary carry circuit will extend the quinary carry or no-carry as a binary carry or no-carry into the adjacent higher position. This is shown in Fig. 1n, for example, where the quinary carry output 157 is coupled to the contacts R113d of the binary carry circuit while the quinary no-carry output 156 is connected to contacts R113f of the binary carry circuit. Tube controlled augend relays.-In each order of the augend there are four relays corresponding to the values 5, 3, 1, 0. Each relay is controlled by a vacuum tube or electron discharge device similar to that described in U.S.A. Specification 2,293,177. A typical example is shown in Fig. 1k in the connection to V.T.4 and its associated relay R36. Each tube comprises a cathode 161, input control grid 162, a screen grid 167, a primary anode 163, a deflector electrode 164, a secondary collector grid 165 and a secondary emitting anode 166. The cathode 161 and deflector 164 are coupled to ground while the anode 163 and cathode 161 are capacitively coupled by a 0.01 microfarad capacitor in order to reduce the inductive kick from the relay. The screen grid 167 is connected through the 240 ohm resistor 168 to the high side of the regulated 75 volt supply. The primary anode 163 which is provided with a small aperture through which electrons emitted by the cathode pass through, is coupled through the 400 ohm. resistor 169 to the relay R36 which in turn is also coupled to the positive side of the 150 volt supply. The electrons which pass through the slot in the anode 163 are directed towards the deflector 164. The deflector 164 causes the electrons that pass out through the aperture to pass through the collector grid 165 and to impinge on the secondary electron emitting anode 166. The collector grid 165 is connected directly to the positive 150 volt supply to keep it more positive than the secondary anode at all times. When a positive' "ON" pu'se is applied to the normally biased control