From owner-freebsd-arch@FreeBSD.ORG  Mon Jun 26 12:55:39 2006
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To: Paul Schenkeveld <fb-arch@psconsult.nl>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Mon, 26 Jun 2006 10:38:28 +0200."
	<20060626083828.GA18912@psconsult.nl> 
Date: Mon, 26 Jun 2006 12:55:00 +0000
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Cc: freebsd-arch@freebsd.org
Subject: Re: Accessing disks via their serial numbers. 
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In message <20060626083828.GA18912@psconsult.nl>, Paul Schenkeveld writes:

>I don't want to change the way the world is and certainly not violate POLA
>but just to add another angle to the discussion, life would be nice if
>we had something like:
>
>  /dev/ad/0
>  /dev/ad/0/whole_disk
>  /dev/ad/0/s1
>  /dev/ad/0/s1a
>  /dev/ad/0/s1c
>
>and
>
>  /dev/ad/<SERIAL> -> 0

This would take a bit of work to implement, currently we do not support
adding DEVFS symlinks in the kernel that point to directory.

Also, from experience, a lot of weird software needs to learn about
all the '/' you insert in disknames.

As far as I know, for ATA the problem is solved with ATA_STATIC_ID,
and IMO it is solved better that way.

This then begs the question if we should instead introduce a generic
DISK_STATIC_ID which all controllers respect ?

For CAM disks I guess this would mean encoding all of (bus,id,lun)
in the device name:

	/dev/da0:0:1

or some such.



-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.