Patent GB-757109-A (GB)
Title: Improvements in or relating to the input of information into a digital differential analyzer
IPC: G06F7/66
Filed: 1953-12-11
Abstract: 757,109. Digital electric calculating-apparatus; electric digital-data-storage apparatus; statistical apparatus. BENDIX AVIATION CORPORATION. Dec. 11, 1963 [Dec. 16, 1952], No. 34589/53. Class 106 (1). In a digital calculator for performing integration and differential analysis, similar to that of Specification 748,267, comprising a set of storage sections and common computer means associated therewith, information is introduced into successive elementary positions of the storage sections from successive positions of a tape having indications such as perforations. The apparatus described includes means (part of which is shown in Figs. 3 and 4) for entering data on the magnetic drum 10 either manually or from a record tape 442, Fig. 7. The logical algebra equations for the entry operations are given in the Specification. The entry circuits consist primarily of bi-stable flip-flop circuits (called " multivibrators ") such as 103, crystal diode gating networks such as 226 and signal-inverting amplifiers such as 123, and are controlled by the clock pulses picked up from channel 24 by head 50, and by outputs from the counters 58 and 84 for marking off pulse times P1-P48 and integrator intervals I1-I22. The method of entry is generally similar to that described in Specification 748,267, a reference pulse being first placed in the Z channel (22 in the present Specification) and being successively shifted to control entry into successive pulse position from P48 I22 to P1 I1 in the Y and R channels (18 and 20). This reference pulse is inserted by closing switch 282 with switch 124 in the right-hand (dataentry) position in which it applies a low potential from battery 128 to amplifier 123. This causes high potentials to be applied from battery 132 and from the amplifier e.g. to diodes 292, 322, Fig. 4, of a coincidence gate also controlled by the counters 58, 84, whereby at the next time P48 I22 a pulse is passed through diode 330 to record head 44 for the channel 22. This pulse is picked up 1055 pulse times later (one pulse time before a complete drum revolution) by head 102 and causes 103 to be triggered. During the following pulse times, flip-flops 104, 105 are successively triggered, the preceding flip-flop being reset. Each flip-flop in its triggered state has a high potential on its left-hand output. Thus, when 282 is re-opened, since positive potentials are applied from amplifier 293 and from the right-hand flipflop 112 (in its normal reset state) to diodes 296, 318, flip-flop 104 causes the reference pulse to be re-recorded without precession via diodes 316,320. Tape input. The tape 442, Fig. 7, has position-defining holes 446 and two series of selectively punched holes 450, 452 corresponding to " 1's " to be recorded in the channels 18 and 20, Fig. 3, respectively. These latter holes are sensed by spring-loaded pawls 454, 456 which operate electric contacts 370, 458. For entry of data from the tape, after a reference pulse has been inserted in channel 22, a switch 203 is moved to the left-hand position and channel filling switches (not shown) are closed (corresponding to depression of buttons described in Specification 748,267. Every time flip-flop 105 is triggered by the reference pulse, a binary counter comprising flip-flops 106, 108, 110 is stepped on (Fig. 9) and every eighth time outputs from this counter cause flip-flop 112 to be triggered 510 (Fig. 9) by the pulse from 102 which is passed through gating network 226, Fig. 3, the flip-flop being reset three pulse time later through gating network 228 controlled by flip-flops 105 and 114. Flip-flop 112 controls diode 308 of a gating network also controlled by 103 so that the reference pulse is re-recorded, through diode 312, one pulse time earlier (P47 I22). Further gating networks (not shown) controlled by flip-flops 104 and 112, the channelselecting switches and contacts 370, 458, Fig. 7, respectively control recording of data in the sensed position on the tape 442 into the correct positions in channels 18, 20, Fig. 3. During the following drum revolution any " 1's " recorded are sensed by the normal reading heads 32, 38, and cause energization through gating networks and one-shot multivibrators (Fig. 6, not shown) of solenoids such as 478 (Fig. 9) for punching a checking tape (Fig. 8, not shown) similar to the control tape 442. The two tapes are stepped on simultaneously by operation of solenoids such as 426, 428, Fig. 7, under control of counter flipflops 108, 110 (512, Fig. 9). Solenoid 426 operates a pawl 434 which coacts with gear 436 on the tap-receiving reel 440, and solenoid 428 operates a dog 448 which coacts with the holes 446. The precessing of the reference pulse and the entry of data recorded in one position of the tape is repeated in the above manner for every eighth revolution of the drum until the whole of the data has been recorded. If, however, there is no data to be recorded in any integrator memory section a hole 450 is provided in the P48 position on the tape corresponding to this section (the P48 position in the Y-channel being normally blank). This hole causes a " 1 " to be recorded in channel 18 which is subsequently read by the head 32, Fig. 3, so as to cause a positive pulse to be applied to diode 252 of a coincidence gating network which is controlled by switch 124 and flip-flop 105 (through cathode follower driver 179), switch 203, counter flip-flops 108, 110 and counters 58, 84 so as to pass such a pulse (except for integrator memory section I1 through clock-pulse-controlled networks 265, 267, 269 and inverting amplifier 277 to reset flip-flop 114 from its normally triggered state. The resultant low potential from the left-hand output of 114 prevents flip-flop 112 being reset through 228 whereby the reference pulse in channel 22 is precessed continually, once per drum revolution. During this time, flip-flop 114 also prevents any new recording being made in channels 18, 20 and any stepping of the control and checking tapes. When the reference pulse has been precessed through all the positions corresponding to the unwanted integrator memory section, gating network 182, controlled by 58, operates to re-trigger 114 through amplifier 240, and flip-flops 106, 108, 110, 112 are reset to their initial states, in preparation for data entry into the next memory section. For the last memory section I1 the reference pulse is always precessed at the slower rate and, after entry has been made in pulse position P1 I1, a gating network comprising diodes 234-260 operates to reset 114, via amplifier 277, and no further data entry occurs, the information on the drum being continually re-circulated until the switch 124 is moved over to the left-hand position to cause a computation to take place on the entered data. Some of the flip-flops, e.g. 104, 105, 110, 112 and 114, in the data-entry circuits may also serve other functions during the computation. Manual input. Data is manually entered on the drum, first in one of the channels 18, 20 and afterwards in the other, as in the apparatus described in Specification 748,267. After the reference pulse has been inserted in channel 22, the switch 203 is moved to the right-hand position, whereby the flip-flops 106, 108, 110, 112, 114 are sequentially operated, in a manner different from that for tape input, under control of " 0 " and " 1 " entry switches 214, 216, Fig. 3. Specification 751,101 also is referred to.