Subject: Re: partition bookkeeping
To: Oleg Polyanski <>
From: Ignatios Souvatzis <>
List: tech-kern
Date: 09/22/1999 22:39:08
On Thu, Sep 23, 1999 at 12:34:57AM +0400, Oleg Polyanski wrote:
> >>>>> "IS" == Ignatios Souvatzis writes:
>  >> >> I'm not sure that it makes our life easier.  Right now we have
>  >> floating >> disk naming scheme - disk detected first will get number `0'
>  >> even if it >> has, for example, SCSI ID 5 so when I add another disk with
>  >> SCSI ID >> number 2 (for example, I would like to add large /opt file
>  >> system) it >> becomes first (i.e.  sd0), not the former `first' disk.
>  >> You cannot mount >> root fs without editing your `/etc/fstab'.  It's
>  >> weird.  Disk naming >> scheme must depend on device physical properties
>  >> (SCSI ID, master/slave >> or something like that).
>  >> 
>  IS> This won't help you to mount root. You have to _know_ at _runtime_ which
>  IS> one it is. As this isn't generally possible (at best, the kernel knows
>  IS> it), install scripts tend to mount kernfs and then mount /kern/rootdev.
>  >>  Sorry, forgot to say `mount root fs for read/write'.
>  IS> Yes, this was evident, and is exactly what I'm referring to.
>  IS> Maybe I should add that for normal booting, root devices tend to not
>  IS> change their name all the time, so having the sysadmin edit fstab once
>  IS> at installation or reconfiguration time is good enough.
> 	Consider my disk has name `sd0' (because it was detected first during
> 	the kernel booting). Later  I will add ZIP  drive and IT will get the
> 	name `sd0' and hard  disk will  become  `sd1'.  Bad  surprise, manual
> 	intervention required.  Something like `/dev/scsi/dsk/c0d0p0' as root
> 	fs unique identifier will help.

If you insist to make your boot drive scsi id 1, and not having any fixed
disk scsi id 0, you can still wire down the sd unit of your root disk in 
your kernel configuration.

Just don't force me to do the same, when I don't need it.