IBM Active Protection System Approach

[Eric Anderson]

Gary Jennejohn wrote:
> Borja Marcos writes:
> 
>>>Søren Schmidt writes:
>>>I think this will need to be tailored to the exact type of "mishap"  
>>>one wants to protect against.
>>
>>     I think that the main purpose of the shock detection system is  
>>to allow data to be recovered from the disk in case the laptop is  
>>broken. By parking the heads asap you can avoid damaging the plates  
>>with the head.
>>
>>     At least that's what I read. The disk won't be necessary usable  
>>after being dropped, but at least the plates should be readable.
>>
>>     In that case, priority number one would be a fast parking of the  
>>head. However, it could lead to a worst-case data loss with  
>>softupdates and the disk cache, isn't it?
>>
> 
> 
> It seems to me that the worst-case scenario, dropping the laptop,
> would result in extremely high G-loading in microsecomds rather than
> milliseconds. Not much can be done to save the disk in such a short
> time.

The idea is for the laptop to recognize when it has begun a fall or 
other sudden change in acceleration, so it parks the heads well before 
impact time.

> A scenario where the user bumps the laptop while in use might be
> helped, though.

Eric



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Eric Anderson        Sr. Systems Administrator        Centaur Technology
Anything that works is better than anything that doesn't.
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