Subject: Re: Dynamic SCSI ids (was: A possible way of handling...)
To: None <tech-kern@NetBSD.ORG>
From: Ignatios Souvatzis <ignatios@cs.uni-bonn.de>
List: tech-kern
Date: 03/29/1997 11:07:38
From: joda@pdc.kth.se (Johan Danielsson)
Date: 29 Mar 1997 04:02:50 +0200
"Chris G. Demetriou" <cgd@cs.cmu.edu> writes:
> It does the "right thing" in most "simple" environments
It does the right thing if you never change your scsi setup. The other
approach (to name devices after scsi-id rather than after the order
they are detected) also works in these simple cases.
No, it doesn't.
On the contrary, the BSD approach is, e.g., useful for installation
setups: it will always find a single disk 0, at whatever target id it
is.
The BSD-approach fails when you move, add or remove units from *any*
chain.
Oh... not really.
At home, I tend to put my root disk at target 0 anyway, to have a
stable singleuser boot with GENERIC kernels.
Would I not do kernel development, I would just wire my normal disks
in the config file, and leave a wildcard entry for changing ones.
If you want to hardwire your disks, you can do it with
sd0 at scsibus? target 0 lun 0
sd1 at scsibus? target 1 lun 0
...
sd7 at scsibus? target 7 lun 0
pretty easily. But what would you do with a disk on a 2nd scsibus?
Btw, what _you_ really would want isn't a mount by physical attributes
like target id (you could change jumpers in between boots as easily as
remove the disk logically in front) but mount by volume name.
Ignatios Souvatzis