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From: Tejun Heo <htejun@gmail.com>
To: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Soeren Sonnenburg <kernel@nn7.de>, Jeff Garzik <jeff@garzik.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: SATA hotplug from the user side ?
Date: Wed, 24 Jan 2007 11:07:25 +0900	[thread overview]
Message-ID: <45B6BF5D.1070300@gmail.com> (raw)
In-Reply-To: <20070123131040.GB13467@khazad-dum.debian.net>

Henrique de Moraes Holschuh wrote:
> On Tue, 23 Jan 2007, Tejun Heo wrote:
>> Henrique de Moraes Holschuh wrote:
>>> Does SATA electrical conector keying let the disk firmware unload
>>> heads before the user manages to pull it out enough to sever power?
>> I don't think so.
> 
> Heh, thought as much. (Good) SCSI hotswap bays notice you pulled the disk
> release lever and issue an START_STOP_UNIT by themselves to the disk well
> before you have time to start pulling the disk out.  I wonder if the SATA
> ones do (I kind of doubt that, SATA seems to attract the el-cheapo, el-crapo
> crowd of manufacturers).

ahci controller spec has places for such thing but I've never seen it
actually implemented.  I'm thinking about a CLI tool to list & control
libata devices including hotplugging, NCQ and other stuff.  Eventually,
it would be really nice to give the user/admin easy gui/web/whatever
tool to watch and control ATA devices.

>>> If it does not, the drive will do an emergency head unload, which is
>>> not good and will likely reduce the drive's lifetime.
>> Probably.
> 
> So, that means it should be explained in the docs that you are to stop the
> disk first, if you can.

Yeap, agreed.

> Even if hald does this automatically, it would still be a very good idea to
> document the proper sequence, IMO...

Agreed.

-- 
tejun

  reply	other threads:[~2007-01-24  2:08 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-12  7:57 Soeren Sonnenburg
2007-01-12 17:04 ` Jeff Garzik
2007-01-12 22:07   ` Soeren Sonnenburg
2007-01-13  1:55     ` Tejun Heo
2007-01-13  7:22       ` Soeren Sonnenburg
2007-01-15  2:21         ` Tejun Heo
2007-01-22  9:04           ` Soeren Sonnenburg
2007-01-22 21:03             ` Henrique de Moraes Holschuh
2007-01-23  6:23               ` Tejun Heo
2007-01-23 13:10                 ` Henrique de Moraes Holschuh
2007-01-24  2:07                   ` Tejun Heo [this message]
2007-01-24  9:09                     ` Soeren Sonnenburg
2007-01-24 15:37                       ` Henrique de Moraes Holschuh
2007-01-25 12:56                         ` Soeren Sonnenburg
2007-01-25 21:56                           ` Henrique de Moraes Holschuh
2007-01-25 21:21                         ` Eric D. Mudama
2007-02-05 11:56                           ` Tejun Heo
2007-02-05 11:50                         ` Tejun Heo
2007-01-23  6:19             ` Tejun Heo
     [not found] <fa.pn1gmGiSlhDVMiPyzEEm1A66vcY@ifi.uio.no>
     [not found] ` <fa.Od11QHN89ZQ9VkFktF6HvxWuLV0@ifi.uio.no>
     [not found]   ` <fa.vsuV8EVipw4cXaHgzWpaf0q1pAA@ifi.uio.no>
     [not found]     ` <fa.8a1kVu4a2ISeaFZcL3migbjZ5N0@ifi.uio.no>
     [not found]       ` <fa.79JzgEcD2u5B9SYqrw3sr5b+iy8@ifi.uio.no>
     [not found]         ` <fa.DH50RMz6OHKG0AoGA/cChsCW8Ig@ifi.uio.no>
2007-01-25  0:33           ` Robert Hancock

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