> If we order per partition -- at least by default, with no priorities
> given to partitions -- we have to seek to the middle or near the end
> of the disk to scribble something (time may be negligible to
> non-trivial), and then we have to seek BACK to near the beginning of the
> disk (for which time will NOT be non-trivial).
>
> Actually, that will happen whether or not we assign priorities to
> different partitions, but I'm leaving it in for train-of-thought.

it's exactly what's going in linux. with whole-disk filesystem partition
(or only /+swap) it works fine, with many partitions LOTS of seeks are
made and disk access is suboptimal.

partitions are just logical idea, while physical disk are real device that
can read/write independently from others (at least should)