CRT Unit
                            CheckSnow Variable

  DECLARATION:  VAR CheckSnow : Boolean;

      PURPOSE:  Enables/Disables snow checking when storing characters
                directly into video memory.

      DEFAULT:  TRUE (when a color text mode is selected)

      REMARKS:  Unlike EGA or monochrome display, interference will result
                on most CGAs if characters are directly stored in video
                memory outside the horizontal retrace intervals.

                When a color text mode is selected, CheckSnow is set to
                TRUE and direct video memory writes will only occur during
                horizontal retrace intervals.

                NOTE: Has no effect when DirectVideo is set to FALSE