If you include RV, UL, BL, RU, or RB in your terminal database file entry, then the HI and LO functions must be included. These two functions set the terminal to normal video/high intensity and normal video/low intensity, respectively. If intensity is not being used, then these should both just set normal video.
On all machines except MS-DOS and Windows, the runtime system ignores the difference between high-intensity spaces and low-intensity spaces when the background color is black. If your terminal is set up to run with black-on-white characters (reverse video) as its default, you should add the entry VB (visible background) to the description of that terminal. This causes spaces to be handled consistently.
If a "magic cookie" style terminal is being used, then HI and LO should not set normal video, but should just set the appropriate intensity. The function NM should be added to set normal video instead. Also, the function sg must be included to tell the Terminal Manager that this is a "magic cookie" type terminal. The sg setting does not take a value, it just has to be present.
A few "magic cookie" terminals ignore HI and LO, so that reverse video fields appear the same regardless of which intensity is used. If you are experiencing this situation, add RA to the terminal's description. This sets the terminal into reverse video using the terminal's alternate intensity (usually low intensity). If RA is used, then RV sets reverse video in the terminal's default intensity.
The function DL should be included in a definition if the default intensity for the terminal is low-intensity. This function is not set to a value, it is just included in the terminal definition.
On some terminals, a clear screen operation uses the currently selected video attribute. For example, if reverse-video were the current attribute, then a clear screen would cause the entire screen to become reverse-video. If the terminal has this property, then AC should be included to indicate this. ACUCOBOL-GT uses this to optimize certain screen displays.