# -Fkeep:

If this option is set to ON, dviout saves locations of often-used fonts to make dviout start quicker (Property Sheets->[Font2]).
This option is especially useful when the -TEXPK: entry contains a <<>><<>> or // construct (for recursive directory search). To erase the record, press [Flush] button.
If one of the following conditions is met, the font information is not recorded.
1. When the font filename matches an -TEXPK: entry with two or more <<>><<>> or // constructs. (-TEXPK: entries as a whole may contain several of such constructs.)
2. When the -TEXROOT: or -TEXPK: parameter is altered after startup.
3. When the font is substituted by the -F: option.
Dviout maintains a score for each fontname-resolution pair. The score is a nonnegative integer not greater than 255. Up to 400 fonts with high scores are recorded. Whether a font is used is examined when dviout quits. If several fonts have the same current score, dviout steps backward in the history of font usage, until the scores becomes inequal.
The score is calculated by the following rules:
1. The score of 64 is given if the font is used for the first time in the record.
2. If the font in the record is not used this time, the new score will be the last score (at the time of previous quit) times 15, divided by 16, plus 16, rounded down to the nearest integer.
3. If the font is in the record but not used this time, the score will be the last value times 15 divided by 16, rounded down to the nearest integer.