Subject: Re: Dynamic SCSI ids (was: A possible way of handling...)
To: None <joda@pdc.kth.se>
From: Ignatios Souvatzis <ignatios@cs.uni-bonn.de>
List: tech-kern
Date: 03/31/1997 14:41:42
I (repeat, _I_) don't WANT to need to call busses in so complicated
ways. I simply only want to name the first disk on the first bus sd0,
and the first tape on the first bus st0, and the first cd-rom on the
first bus scan0, and the first scanner on the first bus scan0. 

For production uses, I sometimes want to nail down things in specific
ways. If so, I do it along my needs.

_You_ can easily implement the spirit of your proposal (although not
the implementation detail, that is, hardcoding it into the scsi
driver), and are free to do so and put it into some include file which
you include in your configurations.  You are even free to publish it.

You should just consider that it is nearly impossible to uniquely name
the number of different scsibusses we have on our 16 ports in a way
that is not confusing. Remember, alone for NetBSD/AMiga we have a
dozen scsi bus _hardware_ incarnations, half of which can be there in
more than one incarnation on a single machine. So what you do might
not be as useful, or as easy, as you think... whether you do it
in-kernel or in-configfile. 

I, _personally_, prefer that you do it in your config file, and don't
force _me_ to learn _your_ numbering scheme.

I, as a portmaster helper, and somebody who sometimes prepares
distribution-style snapshots, prefer that you do it in your config
file, and don't force me to learn your numbering scheme... in fact,
don't force me to write 4 kbytes of sh script just to find out which
disks are there, and whereupon to install the OS. It's much easier to
tell the user "Hey, there are 2 disks, sd0 seems to be Quintum 1234MB,
sd1 seems to be Controtec 4321 GB, where do you want your root disk on?" 

...While the sun3/sun4 portmaster might prefer to name sd0 ... sd3
conforming to what the SUN ROM does, that is to hard-code sd0 at
target 3 lun 0, and sd3 at target 0 lun 0, on whatever bus that
machine has (and nearly all SUNs of that class only _have_ one bus,
whatever that might be).

Regards,
	Ignatios Souvatzis