Improvements in and relating to the electrostatic storage of digital information

摘要

705,513. Digital electric calculating-apparatus. NATIONAL RESEARCH DEVELOPMENT CORPORATION. May 23, 1952 [Feb. 26, 1951], No. 4679/51. Class 106 (1). [Also in Group XL(c)] A method of recording digital information and of reading same, using an electrostatic storage device (C.R.T.) of the type in which each digit is recorded within a digit area on an insulating recording surface, the value of the digit being determined by the state of charge of an elemental area produced by a cathode ray beam, consists in directing the beam upon the elemental area in each of a succession of digit areas to read the information thereon, then, after reading each elemental area, directing the beam to an adjacent area of a preceding digit area and, if one kind of digit is to be recorded, switching it on in order to reduce, by release of secondary electrons, the charge on the associated elemental area. In the known art a Williams type CRT storage tube is operated with an X-time base b, Fig. 1, which holds the beam stationary for a period at each data position. The grid voltage a first switches the beam on for a brief period (t0 &c.) and then, during a subsequent period (t2 &c.), while the beam is given a slight Y- deflection, the beam is again switched on to reduce the first charge by release of secondary electrons from an adjacent area, but only when a "dash" (representing binary digit "one") is to be written. The curve c indicates the output of the reading device when "101" is being read. In accordance with the invention, in order to provide more time between the reading out and re-entry of each digit, an X-time base d is provided whereby, e.g. the reading of a digit in position 2 is followed by the writing in of a "dash" (if appropriate) in position 1 ; this is followed by the reading of the digit in position 3, and so on. The time base d can be produced by combining wave-form f and g. The output of the computor is passed to the "write" unit via an auxiliary store or "shuffle circuit", Fig. 3. A diode D1 is biased negatively at its anode, but receives positive-going resetting pulses at times t0, t01, etc.; a diode D3 is similarly biased and receives positive resetting pulses at times t3, t31, &c. Negative pulses from the computer 16, representing digit "one", cause condenser C1 to be charged and the grid of triode V1 to be held negative until a resetting pulse arrives via diode D1, when the resulting drop of the anode potential at V1 causes a lowering of potential at the grid of triode V2 until a resetting pulse arrives via diode D3; a positive output pulse appears at a terminal T3. An output pulse generator for the "read" unit includes a circuit operating on the same principle. The method can also be applied to the division of numbers by powers of two. Specifications 693,424 and 705,474 are referred to.