Re: [Hdaps-devel] Re: HDAPS, Need to park the head for real

From: Jon Escombe
Date: Fri Aug 19 2005 - 05:07:33 EST



Please make it "echo 1 > frozen", then userspace can do "echo 0 > frozen"
after five seconds.


What if the code to do "echo 0 > frozen" is swapped out to disk? ;)


Emergency head parker needs to be pagelocked for other reasons. You do
not want to page it from disk while your notebook is in free fall.



It's still a very bad idea imho, what if the head parker daemon is
killed for other reasons? The automatic timeout thawing the drive is
much saner.


For hard disk protection, I prefer the idea of the userspace code thawing the drive based on current accelerometer data, rather than simply waking up after x seconds (maybe you're running for a bus rather than falling off a table)...

To get the best of both worlds, could we maybe take a watchdog timer approach, and have the timeout reset by the userspace component periodically re-requesting freeze?

Regards,
Jon.


______________________________________________________________
Email via Mailtraq4Free from Enstar (www.mailtraqdirect.co.uk)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/