Data Output

in electronic computing machines, the set of procedures and technical devices that ensure transmission, to the output of the computer, of final and many inter-mediate (control) results of data processing in order to record them by storing, writing, or visually displaying them. In electronic computers, machine output quantities are represented as continuously changing voltages or currents, graphic or printed materials, or discrete electrical signals. The first form is typical of analog computers, whereas the second characterizes digital computers. In principle it is possible to make mutual conversions of continuous quantities into discrete ones and vice versa, a step called conversion of the representation of a quantity. Comparatively slow data output devices limit the productivity of the electronic computer, and increasing the speed of data output is one of the main lines of development in calculating machines.

From the analog computer, data output is transmitted to different voltage measures, displays, and oscillographs. For measurement and recording of slow-changing voltages a digital voltmeter with a number printer or punching attachment is used. Electronic recorders are used to write on paper tape one or several variables that change over time and are represented in the form of voltage. A display unit with an electron beam tube ensures visual observation of one or several quantities in a time function or in a function of other variables, the measurement of instantaneous values of the quantities observed, and the marking of these quantities with time tags. The display usually is equipped with a photo attachment. Loop oscillographs convert the signals being investi-gated into a shift of the light beam on light-sensitive paper; the oscillograph ensures recording of about ten parameters. However, the complexity of processing oscillograms and their relatively low precision reduces the efficiency of recording.

Data output is transmitted from the digital computer to the computer memory (an external memory device—tape, drum, discs, and others), to punched tapes and cards, to alpha-numeric printers, to cathode-ray tubes with character display such as the Charactron and Typotron), to graph plotters, and so on. The speed of data output to magnetic tape is tens of thousands of characters per second, whereas onto punched cards and punched tape it goes down to several thousand characters a minute. Printing systems have been developed in which characters are shaped on electrostatic and magnetic surfaces. In such devices, charged and magnetized microparticles of the coating are concentrated at certain points of the surface by the action of an electrical or magnetic field; a precise pattern is obtained in this way. Depending on the method of shaping the characters, the speed of electrostatic printing goes from several thousand to several tens of thousands of characters per second. One of the most graphic methods is data output shown on the Charactron or Typotron; here the speed of output reaches several tens of thousands of characters per second. The image on the screen may be photographed.

Where an analog computer and a digital computer work together, exchange of information moves through an appropriate quantity representation converter.

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