Abstract: A method for reducing the redundancy of binary character sequences which are utilized in matrix printing assigns coordinates to each image point in a character matrix and determines and stores data corresponding to the difference between image point coordinates which are necessary to print a particular character. The differences are stored in terms of magnitude and direction of movement within the character matrix in order to control operation of a printing head for printing the character. The code words for each image point contain an operation byte which may direct a "step" or a "skip" coordinate change. A further reduction is achieved by additional information in the form of a multiplication byte which effects multiplication of specified coordinate steps and by an end byte which signifies the end of a particular character. The method may also effect a constant image point displacement by means of a change-over byte so that the printing can be undertaken in cursive script or shadow script.

Abstract: A method and apparatus for effecting the display of symbols, in tabulated form, on the screen of a data-video device, utilizing a data source, an image repetition store and a symbol generator, in which data is fed by the data source identifying the area of the screen in which a tabulator mark is to be depicted, with the symbol generator releasing signals operative to effect the desired display of the tabulator mark. Control may be effected by means of control words from the data source for "tabulator set", "tabulator cancel", and "tabulator advance", as well as for cancellation of tabulator marks of a line, or cancellation of all symbols with the exception of tabulator marks. A writing mark may be employed in connection with the designation and display of a tabulator mark, and the tabulator marks may be disposed in areas with or without the display of symbols therewith. The invention is particularly adapted to applications involving the so-called "rolling-page method" of display.