A number of the screen routines specify the screen-position parameter. In this COBOL system, the top left corner of the screen is row 0, column 0. For example, if you want to change attributes beginning in row 5, column 8, you specify row-number as 4 and column-number as 7.
The CBL_GET_SCR routines enable you to make use of generic line drawing to produce the best possible representation of graphics characters available in any supported environment without having to modify your source programs.