Background fsck

[ada at noether.geekgirls.r-us.com]

David Cuthbert wrote:
> A friend of mine back at Seagate was the servo lead for one of the 
> Cheetah X15 products (LP144? anyway, I've tried my best to drown out the 
> acronyms and silly codes from back then).  As I recall, they had it down 
> so that seeks under a certain distance happened much faster than those 
> above this threshold.  Other drives (other Seagate models, various 
> competitor models, etc.) would show a roughly constant seek time.

well... a seek distance to seek phase graph effectively has three regions:

1.  a linear region.  small distances (<10 tracks, iirc).  fast.
2.  a ballistic region.  logarithmic or sqrt or something which looks like
    that.
3.  a "constant" region.  depending on the choice of function for (2), 
    above a certain distance there's just no real difference in it.