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

[Jon Escombe <lists@dresco.co.uk>]

>>>>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.


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