[en] The TEK11 graphics library was written for use on PDP-11 minicomputers running the RT-11 operating system to drive Tektronix 4010 graphics display terminals. Library subroutines are coded in FORTRAN and assembly language. The library includes routines to draw axes, either linear or semilog, to plot data in terms of logical values without first scaling to screen coordinates, to label graphs, and to plot in a maximum of four regions on the screen. Modes of plotting may be point plot with any character at the point, vector plot, or bar plot. Two features, automatic scaling and windowing, permit the researcher to use computer graphics without spending time first to learn about scaling or ''Tek points'' and preparing long parameter lists for subroutines. Regions on the screen are defined by specifying minima and maxima logical coordinates, i.e., ⁰K or milliseconds, and a region number. After definition, a region may be activated for plotting by calling REGN with the region number as an argument