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Re: Why is it called strategy?

On Tue, 18 Oct 2011, Emmanuel Dreyfus wrote:

> As I understand, at VFS level, VOP_STRATEGY(9) is used for I/O to block
> devices. Where does that name comes from? 

Block devices use the `strategy()' routines to schedule operations 
because, unlike character devices which typically immediately post the 
write opertion to the hardware, they used to go through disksort() so the 
elevator algorithm could be used to optimize disk access.  Hence the 
strategy() routine did not necessarily start the I/O operation, it would 
usually add it to a work queue.


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