Subject: Re: [PATCH] 64 bit scsi read/write
To: andrewm@uow.edu.au (Andrew Morton)
Date: Sat, 14 Jul 2001 09:45:44 +0100 (BST)
Cc: alan@lxorguk.ukuu.org.uk (Alan Cox),
        adilger@turbolinux.com (Andreas Dilger),
        acahalan@cs.uml.edu (Albert D. Cahalan), bcrl@redhat.com (Ben LaHaise),
        kernel@ragnark.vestdata.no (Ragnar Kjxrstad),
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        mike@bigstorage.com, kevin@bigstorage.com, linux-lvm@sistina.com
In-Reply-To: <3B4FBB36.1F692780@uow.edu.au> from "Andrew Morton" at Jul 14, 2001 01:23:34 PM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Sender: linux-kernel-owner@vger.kernel.org

> If, after a power outage, the IDE disk can keep going for long enough
> to write its write cache out to the reserved vendor area (which will
> only take 20-30 milliseconds) then the data may be considered *safe*
> as soon as it hits writecache.

Hohohoho.

> In which case it is perfectly legitimate and sensible for the drive
> to ignore flush commands, and to ack data as soon as it hits cache.

Since the flushing commands are 'optional' it can legitimately ignore them

> If I'm right then the only open question is: which disks do and
> do not do the right thing when the lights go out.

As far as I can tell none of them at least in the IDE world

Alan

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