Re: [Patch] document ext3 requirements (was Re: [RFD] Incremental fsck)

From: Bryan Henderson
Date: Thu Jan 17 2008 - 16:37:29 EST


"Daniel Phillips" <phillips@xxxxxxxxxx> wrote on 01/16/2008 06:02:50 PM:

> On Jan 16, 2008 2:06 PM, Bryan Henderson <hbryan@xxxxxxxxxx> wrote:
> > >The "disk motor as a generator" tale may not be purely folklore. When
> > >an IDE drive is not in writeback mode, something special needs to
done
> > >to ensure the last write to media is not a scribble.
> >
> > No it doesn't. The last write _is_ a scribble.
>
> Have you observed that in the wild? A former engineer of a disk drive
> company suggests to me that the capacitors on the board provide enough
> power to complete the last sector, even to park the head.

No, I haven't. It's hearsay, and from about 3 years ago.

As for parking the head, that's hard to believe, since it's so easy and
more reliable to use a spring and an electromagnet.

--
Bryan Henderson IBM Almaden Research Center
San Jose CA Filesystems

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