18 Jun
2002
18 Jun
'02
1:57 p.m.
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
18 Jun
18 Jun
4:23 p.m.
In the Amiga market, I believe C Ltd. once offered
such a SCSI disk sharing arrangement with their specific
SCSI adapters and software. I never quite believed that
it worked, but maybe it did.
- John
19 Jun
19 Jun
8:43 a.m.
New subject: C Ltd (was Re: One SCSI tape connected to 2 hosts?)
--- John Foust <jfoust(a)threedee.com> wrote:
In the Amiga market, I believe C Ltd. once offered
such a SCSI disk sharing arrangement with their specific
SCSI adapters and software.
They did. I have one C Ltd controller and all the docs.
I never quite believed that it worked, but maybe it
did.
I think that it did work, but not as well as anyone would
expect to use it in a high-demand environment.
C Ltd was an early casualty in the Amiga marketplace.
-ethan
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10:02 a.m.
New subject: C Ltd (was Re: One SCSI tape connected to 2 hosts?)
Ethan Dicks wrote:
--- John Foust <jfoust(a)threedee.com> wrote:
I had one too. I came with an Amiga 1000. I got it working a couple of
times. I sold it last spring with the A1000
In the Amiga market, I believe C Ltd. once
offered
such a SCSI disk sharing arrangement with their specific
SCSI adapters and software.
They did. I have one C Ltd controller and all the docs.
I never quite believed that it worked, but maybe
it did.
I think that it did work, but not as well as anyone would
expect to use it in a high-demand environment.
C Ltd was an early casualty in the Amiga marketplace.
-ethan
__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com
10:44 a.m.
New subject: C Ltd (was Re: One SCSI tape connected to 2 hosts?)
--- "James L. Rice" <jrice(a)texoma.net> wrote:
Ethan Dicks wrote:
Fortunately, I got it used, for free. The original owner, Ohio State,
paid $1,000 for it with a 20MB drive. They threw it out in disgust,
as I recall, after losing another ST506 mech (not ST225, some other
brand) that wasn't even the original - _it_ was a replacement from
what shipped from C Ltd.
I remember being "happy" that at the same time, I used an XT controller
(Everex WX-clone) with a Canadian 8-bit ISA adapter that only cost me
$500 end-to-end for 20MB. When I got a UUCP feed (kumiss.UUCP), I had
to add another ST225 to hold my mail spool.
The "WEDGE" and WX-1 were eventually replaced by a Starboard/Stardrive.
Still have them. Would use them again if I wanted to fire up my
(Rejuvinated) A1000.
-ethan
__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com
C Ltd was an early casualty in the Amiga
marketplace.
-ethan
I had one too. I came with an Amiga 1000. I got it working a couple of
times. I sold it last spring with the A1000 
11:19 a.m.
New subject: C Ltd (was Re: One SCSI tape connected to 2 hosts?)
The "WEDGE" and WX-1 were eventually replaced
by a Starboard/Stardrive.
Still have them. Would use them again if I wanted to fire up my
(Rejuvinated) A1000.
I've got a Tecmar T-disk setup (20MB) on my A1000 and
actually found a spare drive assembly for it a few months ago. It'd
be cool to come up with some of the other matching items Tecmar made
to go with it, such as the modem.
Jeff
--
Home of the TRS-80 Model 2000 FAQ File
http://www.cchaven.com
http://www.geocities.com/siliconvalley/lakes/6757
12:29 p.m.
New subject: Amiga 1000 hard drives (was Re: C Ltd (was Re: One SCSI tape connected to 2 hosts?))
--- Jeff Hellige <jhellige(a)earthlink.net> wrote:
I've seen pictures. I _have_ a T-disk but no controller and no PSU. I
do not recall where I got it, but I'm sure it was 10+ years ago and I'm
sure it was free. My Amiga disk evolution was WEDGE/ST225 -> StarDrive/
Maxtor LXT213S* -> A3000/DEC RZ26.
The T-disk has a DC37 connector for SCSI, and a SCSI<->ST506 bridge inside,
right?
I have the ads trumpeting it from day one. Shame it took a very long
time to hit the market. They could have been at the tippy-top of a
teenie-tiny market. :-)
-ethan
* The LXT213S was $375 for 200MB, semi-new (still under warranty which was
good when the magic smoke got out). I remember being very happy with that
drive. Still have it; it still has AmigaDOS on it. For power, I mounted
it on top of a C= 1571 power supply that I disassembled and ran screws up
through the perforations to keep them attached. There was barely enough
room on the back to use the perforations to screw down a blue-ribbon
connector on 5cm of cable to the drive on top of the PSU (people used to
love to see me bring my Amiga to meetings - they never knew what would be
hanging off the side next; at one point, the dual ST225s were in a
recycled Burroughs dual-full-height floppy cage just like the one I got
a mate to at Dayton this year for $5).
__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com
The
"WEDGE" and WX-1 were eventually replaced by a Starboard/Stardrive.
Still have them. Would use them again if I wanted to fire up my
(Rejuvinated) A1000.
I've got a Tecmar T-disk setup (20MB) on my A1000 and
actually found a spare drive assembly for it a few months ago. It'd
be cool to come up with some of the other matching items Tecmar made
to go with it, such as the modem.
12:49 p.m.
New subject: Amiga 1000 hard drives (was Re: C Ltd (was Re: One SCSI tape connected to 2 hosts?))
I've seen pictures. I _have_ a T-disk but no
controller and no PSU. I
do not recall where I got it, but I'm sure it was 10+ years ago and I'm
sure it was free. My Amiga disk evolution was WEDGE/ST225 -> StarDrive/
Maxtor LXT213S* -> A3000/DEC RZ26.
The PSU is odd in that a single one had leads going to both
the sidecar/controller and to the drive itself. I went from the
T-disk to a GVP HD8+ on an A500 and then to my A3000 after a number
of PC's.
The T-disk has a DC37 connector for SCSI, and a
SCSI<->ST506 bridge inside,
right?
I've never disassembled either the sidecar or the drive
enclosure so I'm not sure what the actual interface is. I started to
take the drive enclosure apart once but it was doing it's best to
stay together and not reveal what was inside!
I have the ads trumpeting it from day one. Shame it
took a very long
time to hit the market. They could have been at the tippy-top of a
teenie-tiny market. :-)
If you ever get any of the ads scanned, I'd be interested in
seeing them.
Jeff
--
Home of the TRS-80 Model 2000 FAQ File
http://www.cchaven.com
http://www.geocities.com/siliconvalley/lakes/6757
5:33 a.m.
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(a)dunnington.u-net.com>
To: <cctalk(a)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
7:01 a.m.
On Wed, 19 Jun 2002, Richard Erlacher wrote:
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.
OK, what exactly makes you say this? I don't have a lot of experience
myself in dealing with low-level SCSI other than connecting devices and
using user-mode software to talk to them, so I don't know. However, I do
know that there are IP over SCSI and probably other things for Linux that
support, if not demand, multiple adaptors/systems being attached to the
SCSI chain. With Linux's 'generic' scsi driver, you should be able to do
just about anything with the adaptor that 1) the driver/hardware supports
and 2) you can think of writing an application for.
-- Pat
7:28 a.m.
Pat Finnegan wrote
With Linux's 'generic' scsi driver, you
should be able to do just
about anything with the adaptor that 1) the driver/hardware
supports and 2) you can think of writing an application for.
I wonder if anyone has done a SCSI HDD (and/or Tape) emulator yet?
I quite fancy the idea of my PC box behaving as a HDD for my MicroVAX3100...
:)
greg
2:46 p.m.
Well, for starters, multiple hosts on a SCSI is a feature that the LINUX
drivers didn't support back in '95 or so when I exhausted my own interest in
such things. Secondly, the SCSI doesn't attempt to effect commands that are
only found on SCSI-II devices in the context of SCSI-I targets, but rather
"just gives up" and complains when it encounters a SCSI-I perfectly capable of
doing what the SCSI-II command wants, though with a couple of commands. Some
drivers for some systems do this, but not the ones in Windows, and not the
ones in LINUX that I saw. Their behavior, in fact, when confronted with some
devices, e.g NODEMs, or tape libraries, or, for that matter, SCSI bus
expanders was quite primitive. From what I recall, they didn't support
command queueing, didn't support disconnect, didn't support chaining, and
wouldn't do a number of operations without being "babysat" by the host.
The drivers did, apparently, work very well for handling disk drives. I don't
know how well they handled CD writers, as that was another issue of the time.
I've only seen a couple of SCSI printers, but they didn't deal at all well
with non-mass-storage devices. One local company developed a CDR/label
printer combo that completely fell apart under the LINUX SCSI. Of course, it
didn't fare well under Windows, either.
Perhaps that's changed, but I would be surprised.
The main annoyance was that if the software attempted to use a SCSI-II
command, and the device was a SCSI-I device, it just went "tilt" and didn't
attempt to recover by using the necessary two commands. Further, when it was
formatting a tape, which took some time, it couldn't do much else on the SCSI.
Dick
----- Original Message -----
From: "Pat Finnegan" <pat(a)purdueriots.com>
To: <cctalk(a)classiccmp.org>
Sent: Wednesday, June 19, 2002 10:01 AM
Subject: Re: One SCSI tape connected to 2 hosts?
On Wed, 19 Jun 2002, Richard Erlacher wrote:
> 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.
OK, what exactly makes you say this? I don't have a lot of experience
myself in dealing with low-level SCSI other than connecting devices and
using user-mode software to talk to them, so I don't know. However, I do
know that there are IP over SCSI and probably other things for Linux that
support, if not demand, multiple adaptors/systems being attached to the
SCSI chain. With Linux's 'generic' scsi driver, you should be able to do
just about anything with the adaptor that 1) the driver/hardware supports
and 2) you can think of writing an application for.
-- Pat
8070
days inactive
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11 comments
8 participants
participants (8)
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ClassicComputers＠bouncy-castle.demon.co.uk -
edick＠idcomm.com -
erd_6502＠yahoo.com -
jfoust＠threedee.com -
jhellige＠earthlink.net -
jrice＠texoma.net -
pat＠purdueriots.com -
pete＠dunnington.u-net.com