From mboxrd@z Thu Jan  1 00:00:00 1970
From: Antonio Perez <ap23563m@gmx.com>
Subject: Re: About seting up Raid5 on a four disk box.
Date: Wed, 14 Oct 2009 10:53:43 -0400
Message-ID: <hb4olr$6to$1@ger.gmane.org>
References: <hb1udb$6t1$1@ger.gmane.org> <70ed7c3e0910130704l1f1f7f0ar66271d85295c667b@mail.gmail.com> <hb2470$rol$1@ger.gmane.org> <70ed7c3e0910130810r58ab391id2fbfdff6200dcd8@mail.gmail.com> <hb3qpa$6ep$1@ger.gmane.org> <70ed7c3e0910132340q1c4acdfbxa6938261088acca3@mail.gmail.com> <hb4hjp$cg8$1@ger.gmane.org> <70ed7c3e0910140641x74c12a75k6f00df2ed3cbade0@mail.gmail.com>
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Majed B. wrote:

> Your applications can request as much files as they want regardless of
> their location, but the mechanical heads move together, so they can be
> at a single location at a point of time reading a single stream of a
> file (or multiple files if they were next to each other on the
> physical platter).

Yes that's completely correct, and it's the job of the "elevator" (*) on the 
"md" code to decide which sector, and in what order, such sectors will be 
serviced. If the "elevator" is aware of the underlying hardware, it will do 
the right thing if there are several md or just one.

*(I am not an expert on this, is just what I got from Robin)

-- 
Antonio Perez