The font used for labelling in XP was originally created by Bill Clegg by 
digitizing the strokes of a lettering tool.

To create the XP-PrimeXP.ttf, I did the following:

1) Made a .plt file in XP with all the characters except the backslash, which 
   I could not get to render.  
2) Converted the .plt to postscript.
3) Split the postscript into 93 separate .svg files, one for each character, 
   using Python.
4) Combined all the 93 .svg files into a single .ttf with a reversed copy of 
   the slash character to act as the backslash. Again, this was done using
   Python.
5) Tweaked the glyph sizes to make the strokes a uniform width and shortened 
   the straight parts of i,j,! to make the gaps more obvious (GlyphrStudio).  