> > I'm also still not sure how many ``some'' amounts to.  Is it commonplace,
> > or rare?  Something that only expensive drives do?  (Most drives still
> > have RPM numbers associated with them; if they achieve the differing
> > densities by rotating at different speeds, then a single RPM is at best
 [...]
> I'd say all modern drives have varying numbers of sectors per track... and

So if a modern drive lists a single RPM rating, what (if anything) is one
to make of that?  Average-per-cylinder?  Average-per-sector?  Minimum?  
Maximum?  Or is it some kind of effective RPM (based on some nominal
geometry and the speed at which a single block passes under the drive
head)?

> it's not that the data density really varies; the outside tracks have more
> area, and hence can fit more sectors.

Erm, yeah.  I was thinking roughly backwards.  (^&  (It's easier than
thinking forwards, since you just have to follow the tracks...)


  "I probably don't know what I'm talking about." --rauch@eecs.ukans.edu