*BSD News Article 21108


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From: adam@veda.is (Adam David)
Newsgroups: comp.os.386bsd.bugs
Subject: Re: Problem with Julian's SCSI drivers
Message-ID: <CDEzuF.519@veda.is>
Date: 15 Sep 93 21:32:24 GMT
References: <26reei$e4o@news.ysu.edu> <CD7EyC.4Ax@nas.nasa.gov> <CDErsF.1Cx@cbnewsj.cb.att.com>
Organization: Veda Systems, Iceland
Lines: 33

dwex@mtgzfs3.att.com (David E. Wexelblat) writes:

[about dynamically configured device numbers]
>Which is a horribly bad way to do things.  SVR4 does this, too.  I hate it.
>What happens when you remove a device, or one dies?  If I have disks at
>SCSI IDs 0, 1, and 2, and disk 1 dies, then the system will see disk 2
>as disk 1 at boot time, and all of my filesystems will fail to get mounted
>or get mounted from the wrong disk.

Disks don't die :-)

Besides, if a disk early in fstab fails, the system wouldn't be much use
anyway.

>Who could possibly think that this is a good idea?  What is wrong with
>always having the SCSI ID in the name/minor-number?  It seems the ONLY
>correct way to do things.

It saved me having to dismantle and fiddle with the hardware once when I had a
working kernel configured for 2 disks and /usr on the third disk (by SCSI id).
All I had to do to get a more or less normal base system up again was to
unplug the second disk, then I could recompile a working 3-disk kernel. 

Normally, however I would agree with the original complaint that assigning
device ids in the order that disks are found is often a silly idea. What I
would like to see is a file that maps SCSI ids to device ids and back.
It could either be compiled into the kernel or read from /etc/scsitab.
Editing /etc/scsitab would have fixed my emergency more simply and perfectly,
if that could have somehow be read at boot time for the initial device
configuration.

--
adam@veda.is