So what exactly is 1/256 of a character width?

[D. Alvarado]

I noticed these are the units by which HSSFSheet measures its columns.  I was 
wondering if this is 
the same as advance width (the arcane metric used by the FontMetrics package), if 
there is an 
acceptable conversion, or if 1/256 char width referes to something entirely different 
(like points).

Thanks, Dave