Laptop disk spindown

[George Mitchell]

Smartctl reports that my laptop disk has started and stopped
101,798 times in 2,027 hours of operation, or roughly once a
minute.  I imagine that saves wear and tear on the disk, but
it also makes the laptop seem remarkably sluggish for an A8
based system.  Isn't there some sysctl that will lengthen the
idle time before stopping the disk?  I don't see one in the
ada man page.                                     -- George