There's little question that this can be made to work. It should work without
the addition of any hardware. SCSI expanders are usedable to add LUN's to a
given SCSI ID. However, those are not supported by all adapters and even
fewer OS'.
However, it's not within the scope of most OS' in that the drivers are
generally written with the assumption, not necessarily a correct one, that the
host adapter is the only one attached to the SCSI. SCSI is an I/O channel,
not just a mass-storage interface, and the scope of the drivers used in most
operating systems is quite a bit less than a complete implementation of the
standard. A SCSI should be capable of all the capabilities in the standard,
including determining the capabilities of every device on its bus, including
the SCSI level (-I, -II, -III) and width (8-bit, 16-bit, 32-bit) of the data
channel, not to mention support for extensibility via LUN, and bridging to
other channel types (e.g. to ethernet, fibre-channel, USB, etc, as offered via
some devices. I know of no implementation that comes any further than about
10% of this distance.
It's true, Windows is not a candidate for this sort of experiment, since it
goes out willy-nilly tagging the resources it thinks it has every second or
so. You'd think LINUX would have a fairly decent SCSI channel interface, but
it seems to be even more limited than the ones in Windows.
Dick
----- Original Message -----
From: "Pete Turnbull" <pete_at_dunnington.u-net.com>
To: <cctalk_at_classiccmp.org>
Sent: Tuesday, June 18, 2002 4:57 PM
Subject: Re: One SCSI tape connected to 2 hosts?
> On Jun 18, 13:40, Geoff Reed wrote:
> > There are SCSI sharing devices out there that will allow one device to be
> > hooked to 2 machines concurrently.
>
> You can do it directly providing the controllers (and their hosts) are
> well-behaved (which lets Windows off the hook). Back in the days when a
> SCSI disk of any size cost nearly as much as the computer you might want to
> attach it to, one enterprising company produced a system for the Acorn
> Archimedes which allowed six Archimedes computers to share one SCSI disk
> (and, I think, to "talk" to each other). I saw it working at an
> exhibition, and I think it was made by Lingenuity. You might be able to
> get more information from their sister comapany, Lindis:
> http://www.lindis.co.uk, or from Jack Lillingston at Castle Technology:
> http://www.castle.uk.co/
> (no that's not a typo, it is uk.co not co.uk)
>
> --
> Pete Peter Turnbull
> Network Manager
> University of York
>
Received on Wed Jun 19 2002 - 09:33:22 BST