I listened to this recording this weekend and am convinced that I've never heard this particular piece before. That's kind of shocking since the Partitas are some of the most important pieces in the Bach keyboard pieces. I realized that I'd never owned a recording of the complete Partitas, I don't know why, just never got around to buying one. I do have the score but I never studied this particular one. I'm sure I'd have remembered some of the more unusual features of the writing, the Burlesca and Scherzo movements (very unusual for Bach). How someone could get as old as I am and still not have heard or played all of Bach isn't that hard to understand, the guy wrote a huge amount of music, just about every piece a major masterpiece. There are Cantatas I've never heard. Still, for someone in my position it's kind of shameful.
Update: Looking around for information this weekend I came across this really interesting paper, Johann Sebastian Bach's Clavichord Technique Described by Griepenkerl by Miklos Spanyi. It has some really useful and eye-opening information, including the fact that Griepenkerl was sort of a direct musical descendant of J. S. Bach through his son Wilhelm Friedmann and Johann Nikolaus Forkel, one of W.F.'s students who was also J. S. Bach's first biographer. It makes me want to read Forkel's biography, something that wasn't considered to be one of the most important sources when I was in school. If he studied with the musician for whom some of the greatest didactic pieces in history were written, he must have learned somethings that would reveal a more authentic performance practice. Forkel would certainly have tried, hard to accurately pass on J. S. Bach's preferences as passed on to him by Bach's son and one of his most famous pupils.