Re: [PATCH 3/5] libata: Implement disk shock protection support

[Henrique de Moraes Holschuh <hmh@hmh.eng.br>]

On Tue, 05 Aug 2008, Theodore Tso wrote:
> The real right answer though is to buy one of the laptop drives (such
> as the Seagate Momentus 7200.2 or 7200.3) which has the anti-shock
> detection built directly into the hard drive.  That way you don't have
> to have a daemon that sits in the OS waking up the CPU some 20 to 30
> times a second and burning up your battery even when the laptop is
> idle.

Make that 50 times a second for the kernel over a slow LPC bus IO path, plus
whatever userspace needs to process that data and feed it back as an UNLOAD
IMMEDIATE request...

Yes, doing it inside the HD itself is *MUCH* better.  But only very few
disks do it, so far, I only know of those Seagates.  And they are available
only on SATA.  So, many thinkpad owners will want "software-based" HDAPS for
at least five more years, maybe more (thinkpads REALLY have a long useful
life, we still see a good number of T23 in heavy use...).

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh