The Score Width controls the number of columns used by DrumBurp to display the score:
Each space where a note can go takes up a column, as does each bar line between measures and at the start and end of each staff. The abbreviated drum names at the beginning of each staff take up two columns. DrumBurp builds staffs of measures so that the total number of columns used by a staff is less than the score width. Whenever the score width changes, or the number of columns used by a measure changes, DrumBurp recalculates which measures should be on which staff.
For example, in the picture above, each measure takes up 16 columns for a total of 64 columns. There are 5 bar lines, and 2 columns used by the drum names, for a total of 71 columns. The score width is 80 columns. The next measure is 16 columns wide, so it doesn’t fit in the remaining 9 columns of space that we have available.
The reason that DrumBurp makes you control the number of columns in the score manually is that you might want to format your score differently for different purposes, without changing the content itself. For example, when exporting to ASCII tab it is conventional to limit your text to 80 characters in width. When printing out your score, you want it to use the width of the page nicely, so you can use the Fit To Page option to make sure it does. However, when editing your score, or listening to it playing back, you might want to use as much of your computer screen as possible: you can use the Fit To Screen option to set the score width appropriately. The Fit To Screen and Fit To Page options are highlighted below: