[828] in linux-scsi channel archive
Re: SCSI over IP / IP over SCSI
daemon@ATHENA.MIT.EDU (Matthias Urlichs)
Mon Oct 21 18:38:40 1996
From: Matthias Urlichs <smurf@smurf.noris.de>
To: eowmob@exp-math.uni-essen.de (Michael Weller)
Date: Mon, 21 Oct 1996 12:35:34 +0200 (MET DST)
Cc: smurf@smurf.noris.de, linux-net@vger.rutgers.edu,
linux-scsi@vger.rutgers.edu
In-Reply-To: <Pine.3.89.9610211142.B102806-0100000@werner.exp-math.uni-essen.de> from "Michael Weller" at Oct 21, 96 11:59:40 am
Hi,
Michael Weller wrote:
>
>> Sharing a drive is not the problem.
>
>Hmm. from my look at the SCSI standard with regards to reservation
>conflicts I tend to disagree, even not thinking on both machines scanning
>the disks and trying to mount/access them. But then, certainly it is only a
>problem of proper scsi-drivers.
>
We're not trying to reserve anything. Both systems will initally boot from
/dev/sda (or whatever) via the BIOS. The SCSI standard does say that you're
not allowed to say "I'm sorry, I'm busy, somebody else is reading right
now, try again later" (or so I remmeber).
The only way to boot Linux in such an environment is to have an initial
disk (right now, this has to be a RAM disk (*)) with a linuxrc script which
figures out your SCSI ID, and sets /proc/sys/kernel/real-root-dev
appropriately.
(*) The very good reason for the RAM disk requirement is, I'm sure, that
nobody has thought of any need to initially boot from a hard disk partition
which is not the one you want to be your "real" root to reside on.
Well, with multiple hosts on a SCSI bus you do need to do this...
>Certainly (a) and (b) are important points. I can't understand the Adaptec
>reference here though. Once upon a time I had a problem with a linux
>driver for an Adaptec card and once I found the FAX no. of our national
>Adaptec office they mailed a detailed hardware manual (for free, of
>course) which also explains in detail how to do (a) and (b) at hardware
>register level.
>
That's nice, but others have apparently had different experiences with
Adaptec. See the linux-scsi list for detaiils.
--
Man will occasionally stumble over the truth, but most of the time
he will pick himself up and continue on.
-- Winston Churchill
--
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