Patent GB-801002-A (GB)
Title: Data storage device
IPC: G11C11/406
Filed: 1954-12-15
Abstract: 801,002. Electric digital-data-storage apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 15, 1954 [Dec. 18, 1953], No. 36285/54. Class 106 (1). In a data storage device, the data is regenerated by charging a condenser through switching means during a first time interval, and discharging it through the switching means during a second time interval in response to a signal developed during the first interval as a result of an initial uncharged state of the condenser. The storage system shown is similar to that employed in the computer described in Specification 800,273, and comprises a matrix of storage elements, Fig. 1a, in which each column stores a digit in a 7-bit biquinary code, the rows corresponding to the bits B5, B0, Q4 . . . Q1, Q0 respectively (only four shown). Storage element. Each element comprises a condenser and two series-connected diodes. A " 0 " is represented by a charge on the corresponding condenser and a " 1 " or " bit " by no charge. Suppose e.g. that condenser 173 is uncharged so that both points B and D are at - 50 v. (Fig. 2, left). A positive-going pulse at A will pass through diode 176 and charge the condenser, thus producing a positive output at D which is fed over line 193 to a regeneration control circuit, Fig. 1b, which then causes a square positive-going pulse, Fig. 2, to be fed back to D after one digit period at the same time as a negative-going pulse is applied to point C. The condenser then discharges through diode 177 and at the end of the pulses both points B and D return to - 50 v. If, however, the condenser is charged, so that B is at 0 v. (Fig. 2, right), the pulse at A produces no appreciable effect at D, and the point B remains at 0 v. when the negative-going pulse is applied at C. The condition of the condenser is thus regenerated in each case. Storage system. Timing pulses obtained from circuit 180, Fig. 1b, controlled by spots on a rotating magnetic drum 190 cause the stored digits to be regenerated sequentially column by column. Thus, the positive-going pulse at A (row B5, digit column D8U), Fig. 1a, is obtained from cathode follower 178 in response to coincidence of the positive portions of waveforms DG7U, NAP, Fig. 3, at diode gate or switch 179; and the negative-going pulse at C is obtained from cathode follower 182 and inverter 181, in response to coincidence of DG8U, NAP, the cathode follower simultaneously supplying the positive-going charging pulse to condensers such as 174 in the next column D9U. A positive output from D (Fig. 2, left) on line 193 is passed via amplifier 194 and cathode follower 195 to a bistable " latch unit," similar to that described in Specification 710,554, [Group XL (c)], comprising a double triode inverter 198 and feedback loop including cathode follower 199. The positive pulse from 195 switches 198 so that the left side is conducting and, when the latch unit is reset by the next pulse AP, Fig. 3, applied via inverter 204, a positive output pulse is sent via cathode follower 201 to switch a further latch unit 202, 203 which is reset by the next pulse AP via inverter 205. The consequential one-digitperiod positive output on line 218 applied to diode switch 215, allows a positive square pulse to be fed back, when regeneration is required, through cathode follower 213, " even digit" switch 212 and cathode follower 208 to the line 193 (Fig. 2, D). Similarly, if the positive-going pulse from 182, Fig. 1a, produces a positive output from condenser 174 at point H on line 184 such output causes sequential operation of the two latch units through amplifier 185 and cathode follower 186. In this case, the regeneration pulse from 213, occurring during the " odd digit " period DG9U, is fed back to the line 184 through switch 211 and cathode follower 206. The other condensers in the odd and even digit columns are similarly connected to lines 184, 193 respectively, and the " odd digit " and " even digit " waveforms, Fig. 3, control, in addition to switches 211, 212, amplifiers 194, 185 through inverters 196, 197. New information may be entered through switch 217 or from source 200 through switch 214. Also, the stored information may be shifted left through switch 216 controlled by the output of latch 198, 199 on line 219. Circuits 210, similar to that shown in detail, are associated with the other rows of the matrix. In a modification (Fig. 4, not shown), the storage condensers are connected to radiofrequency-controlled gaseous switching tubes. Specification 801,001 also is referred to.