16 Jun
2002
16 Jun
'02
2:42 a.m.
I've noticed that my MV3100's SCSI host ID's are set to 6 - I thought
this odd, as host ID's are usually 7. Are all MV3100's set to 6, or is
mine unique? Anyway, I thought since my PC's host ID is 7, I could
connect my SCSI tape drive to both systems. So I ran a cable from one
connector on the back to my PC, and a cable from the other connector to
my MV3100. I figure it's a properly terminated chain, as each host
controller is terminated (I know the PC is, I assume the MV3100 is).
It *seems* to work OK. But can anyone tell me for sure if this is
"legal"? I'm sure I'm looking for trouble if I try to use the same tape
drive from both systems at the same time, but as long as I don't do
that, is this an okay setup? It would sure beat changing cables every
time I want to move the tape drive from one system to the other.
- Bob
16 Jun
16 Jun
8:16 a.m.
On Sun, 16 Jun 2002, Bob Lafleur wrote:
I've noticed that my MV3100's SCSI host
ID's are set to 6 - I thought
this odd, as host ID's are usually 7. Are all MV3100's set to 6, or is
mine unique? Anyway, I thought since my PC's host ID is 7, I could
connect my SCSI tape drive to both systems. So I ran a cable from one
connector on the back to my PC, and a cable from the other connector to
my MV3100. I figure it's a properly terminated chain, as each host
controller is terminated (I know the PC is, I assume the MV3100 is).
It *seems* to work OK. But can anyone tell me for sure if this is
"legal"? I'm sure I'm looking for trouble if I try to use the same
tape
drive from both systems at the same time, but as long as I don't do
that, is this an okay setup? It would sure beat changing cables every
time I want to move the tape drive from one system to the other.
Bob,
A few of the older SCSI "how-to" pages diagrammed just such a setup.
I've never seen it done in real life, but it always looked like a
reasonable idea to me, too.
I just found out, talking to my boss, that both native Solaris and
Veritas Volume manager support that type of configuration.
It's also relevant that you can run IP-over-SCSI between hosts, and
ISTR that the original Beowulf code provided just that for fast
intra-cluster communication.
Doc
9:27 a.m.
Hi Bob,
I've tried to connect a tape drive between a Windows 95? machine
and a FreeBSD machine with limited success. Windows issues a bus
reset whenever it gets confused (translate a lot!) which will
abort any transfer taking place from the MV3100. FreeBSD seemed
to be better about not bothering with the bus except for reboots,
but wasn't reliable WRT transfers.
What you really need is a PC driver that accepts the fact it isn't
the highest priority device, and leaves the bus reset line alone.
Clint
On Sun, 16 Jun 2002, Doc wrote:
On Sun, 16 Jun 2002, Bob Lafleur wrote:
I've noticed that my MV3100's SCSI host
ID's are set to 6 - I thought
this odd, as host ID's are usually 7. Are all MV3100's set to 6, or is
mine unique? Anyway, I thought since my PC's host ID is 7, I could
connect my SCSI tape drive to both systems. So I ran a cable from one
connector on the back to my PC, and a cable from the other connector to
my MV3100. I figure it's a properly terminated chain, as each host
controller is terminated (I know the PC is, I assume the MV3100 is).
It *seems* to work OK. But can anyone tell me for sure if this is
"legal"? I'm sure I'm looking for trouble if I try to use the same
tape
drive from both systems at the same time, but as long as I don't do
that, is this an okay setup? It would sure beat changing cables every
time I want to move the tape drive from one system to the other.
Bob,
A few of the older SCSI "how-to" pages diagrammed just such a setup.
I've never seen it done in real life, but it always looked like a
reasonable idea to me, too.
I just found out, talking to my boss, that both native Solaris and
Veritas Volume manager support that type of configuration.
It's also relevant that you can run IP-over-SCSI between hosts, and
ISTR that the original Beowulf code provided just that for fast
intra-cluster communication.
Doc
11:56 a.m.
"Clint Wolff (VAX collector)" wrote:
Hi Bob,
I've tried to connect a tape drive between a Windows 95? machine
and a FreeBSD machine with limited success. Windows issues a bus
reset whenever it gets confused (translate a lot!) which will
abort any transfer taking place from the MV3100. FreeBSD seemed
to be better about not bothering with the bus except for reboots,
but wasn't reliable WRT transfers.
What you really need is a PC driver that accepts the fact it isn't
the highest priority device, and leaves the bus reset line alone.
Clint
On Sun, 16 Jun 2002, Doc wrote:
> On Sun, 16 Jun 2002, Bob Lafleur wrote:
>
> > I've noticed that my MV3100's SCSI host ID's are set to 6 - I
thought
> > this odd, as host ID's are usually 7. Are all MV3100's set to 6, or is
> > mine unique? Anyway, I thought since my PC's host ID is 7, I could
> > connect my SCSI tape drive to both systems. So I ran a cable from one
> > connector on the back to my PC, and a cable from the other connector to
> > my MV3100. I figure it's a properly terminated chain, as each host
> > controller is terminated (I know the PC is, I assume the MV3100 is).
> >
> > It *seems* to work OK. But can anyone tell me for sure if this is
> > "legal"? I'm sure I'm looking for trouble if I try to use the
same tape
> > drive from both systems at the same time, but as long as I don't do
> > that, is this an okay setup? It would sure beat changing cables every
> > time I want to move the tape drive from one system to the other.
>
> Bob,
> A few of the older SCSI "how-to" pages diagrammed just such a setup.
> I've never seen it done in real life, but it always looked like a
> reasonable idea to me, too.
> I just found out, talking to my boss, that both native Solaris and
> Veritas Volume manager support that type of configuration.
> It's also relevant that you can run IP-over-SCSI between hosts, and
> ISTR that the original Beowulf code provided just that for fast
> intra-cluster communication.
>
> Doc
>
>
I've seen that done with SCSI HD's and Amigas, but the booting was
iffy. sometimes it worked, sometimes it would hang.
Too bad SCSI is underused; it is already overpriced. But what you can
(or could) do with it . . . .
Gary Hildebrand
St. Joseph, MO
5:33 p.m.
I remember an article or newsgroup post about five years ago that discussed
this. I remember there was a fellow in Germany who was using SCSI ID=4 for
one system's host adapter while he used ID=7 on the other.
I've found that Windows hits my SCSI channels at about 1 Hz, however, so this
procedure is not likely to work if Windows is one of the players. I have a
three-channel controller and it clearly shows activity on each channel at
about that rate. The odd thing is that the CDROM doesn't see a hit, but the
tape drive, which the Win98 backup program doesn't even see, though the device
manager does, gets tagged each time the bus is fiddled with. This makes for a
lot of waiting when the tape drive is doing an eject or a retension operation,
for which it would disconnect if Windows drivers supported that sort of thing.
When I was at Martin, we used a couple of ADAPTEC AHA1540's to try to
communicate between two PC/AT's. It made for quite a bit of raw bandwidth,
but was difficult to wade through the protocol. That was before Windows, BTW,
and success was limited to "making it work" but never was pushed to the point
of actually doing useful work.
Dick
----- Original Message -----
From: "Clint Wolff (VAX collector)" <vaxman(a)earthlink.net>
To: <cctalk(a)classiccmp.org>
Sent: Sunday, June 16, 2002 3:27 PM
Subject: Re: One SCSI tape connected to 2 hosts?
Hi Bob,
I've tried to connect a tape drive between a Windows 95? machine
and a FreeBSD machine with limited success. Windows issues a bus
reset whenever it gets confused (translate a lot!) which will
abort any transfer taking place from the MV3100. FreeBSD seemed
to be better about not bothering with the bus except for reboots,
but wasn't reliable WRT transfers.
What you really need is a PC driver that accepts the fact it isn't
the highest priority device, and leaves the bus reset line alone.
Clint
On Sun, 16 Jun 2002, Doc wrote:
On Sun, 16 Jun 2002, Bob Lafleur wrote:
I've noticed that my MV3100's SCSI host
ID's are set to 6 - I thought
this odd, as host ID's are usually 7. Are all MV3100's set to 6, or is
mine unique? Anyway, I thought since my PC's host ID is 7, I could
connect my SCSI tape drive to both systems. So I ran a cable from one
connector on the back to my PC, and a cable from the other connector to
my MV3100. I figure it's a properly terminated chain, as each host
controller is terminated (I know the PC is, I assume the MV3100 is).
It *seems* to work OK. But can anyone tell me for sure if this is
"legal"? I'm sure I'm looking for trouble if I try to use the same
tape
drive from both systems at the same time, but as long as I don't do
that, is this an okay setup? It would sure beat changing cables every
time I want to move the tape drive from one system to the other.
Bob,
A few of the older SCSI "how-to" pages diagrammed just such a setup.
I've never seen it done in real life, but it always looked like a
reasonable idea to me, too.
I just found out, talking to my boss, that both native Solaris and
Veritas Volume manager support that type of configuration.
It's also relevant that you can run IP-over-SCSI between hosts, and
ISTR that the original Beowulf code provided just that for fast
intra-cluster communication.
Doc
21 Jun
21 Jun
2:12 a.m.
At 03:16 PM 16/06/2002 -0500, Doc wrote:
On Sun, 16 Jun 2002, Bob Lafleur wrote:
Of course Digital (and Compaq) supported systems with shared SCSI storage
under OpenVMS alpha - not surprisingly they were known as SCSI clusters.
You still needed ethernet for SCS traffic but it certainly worked.
Huw Davies | e-mail: Huw.Davies(a)kerberos.davies.net.au
| "If God had wanted soccer played in the
| air, the sky would be painted green"
I've noticed that my MV3100's SCSI host
ID's are set to 6 - I thought
this odd, as host ID's are usually 7. Are all MV3100's set to 6, or is
mine unique? Anyway, I thought since my PC's host ID is 7, I could
connect my SCSI tape drive to both systems. So I ran a cable from one
connector on the back to my PC, and a cable from the other connector to
my MV3100. I figure it's a properly terminated chain, as each host
controller is terminated (I know the PC is, I assume the MV3100 is).
It *seems* to work OK. But can anyone tell me for sure if this is
"legal"? I'm sure I'm looking for trouble if I try to use the same
tape
drive from both systems at the same time, but as long as I don't do
that, is this an okay setup? It would sure beat changing cables every
time I want to move the tape drive from one system to the other.
Bob,
A few of the older SCSI "how-to" pages diagrammed just such a setup.
I've never seen it done in real life, but it always looked like a
reasonable idea to me, too.
I just found out, talking to my boss, that both native Solaris and
Veritas Volume manager support that type of configuration.
It's also relevant that you can run IP-over-SCSI between hosts, and
ISTR that the original Beowulf code provided just that for fast
intra-cluster communication.
2:48 a.m.
I guess I've abandoned the idea of hooking the tape drive to both
systems. It sort of worked, but I found when I had it connected this
way, when backing up under Windows, the drive would suddenly become
unavailable. Sometimes it would run for an hour, and then this would
happen. I don't know if the VMS system was sending it a reset, or what.
I didn't use it enough under VMS to know if Windows was interfering from
that side, but I did a few medium length tests and it seemed to be OK.
I'll just throw the DDS-2 drive into the MicroVAX (I might have to use
some sort of mickey-mouse mounting system if I can't find a mounting
bracket for a BA42B case) and find another drive for the PC.
- Bob
-----Original Message-----
From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]
On Behalf Of Huw Davies
Sent: Friday, June 21, 2002 10:12 AM
To: cctalk(a)classiccmp.org
Subject: Re: One SCSI tape connected to 2 hosts?
At 03:16 PM 16/06/2002 -0500, Doc wrote:
On Sun, 16 Jun 2002, Bob Lafleur wrote:
I've noticed that my MV3100's SCSI host
ID's are set to 6 - I
thought this odd, as host ID's are usually 7. Are all MV3100's set
to 6, or is mine unique? Anyway, I thought since my PC's host ID is
7, I could connect my SCSI tape drive to both systems. So I ran a
cable from one connector on the back to my PC, and a cable from the
other connector to my MV3100. I figure it's a properly terminated
chain, as each host controller is terminated (I know the PC is, I
assume the MV3100 is).
It *seems* to work OK. But can anyone tell me for sure if this is
"legal"? I'm sure I'm looking for trouble if I try to use the same
tape drive from both systems at the same time, but as long as I
don't do that, is this an okay setup? It would sure beat changing
cables every time I want to move the tape drive from one system to
the other.
Bob,
A few of the older SCSI "how-to" pages diagrammed just such a setup. I've never seen it done in real life, but it always
looked like a
reasonable idea to me, too.
I just found out, talking to my boss, that both native Solaris and
Veritas Volume manager support that type of configuration.
It's also relevant that you can run IP-over-SCSI between hosts, and
ISTR that the original Beowulf code provided just that for fast
intra-cluster communication.
Of course Digital (and Compaq) supported systems with shared SCSI
storage
under OpenVMS alpha - not surprisingly they were known as SCSI clusters.
You still needed ethernet for SCS traffic but it certainly worked.
Huw Davies | e-mail: Huw.Davies(a)kerberos.davies.net.au
| "If God had wanted soccer played in the
| air, the sky would be painted green"
11:13 a.m.
I rather hate to tell you this, but, backing up Windows, depending, I guess,
on which software package in use at the time, your tape drive will occasionall
disappear anyway. I've yet to see a backup package, for Windows 9x anyway,
that doesn't lose SCSI tape drives from time to time. In fact it doesn't
manage removabel SCSI disk drives terribly well either.
In short, it's not the tape drive or the SCSI hookup, probably, but is more
than likely the stupid and short-sighted way in which the SCSI subsystem under
Windows is implemented.
What you might find works pretty well, as compromises go, is to put a
terminator at the tape drive, assign it the appropriate address, and simply
attach it to one subsystem or the other as needed.
Dick
----- Original Message -----
From: "Bob Lafleur" <bob_lafleur(a)technologist.com>
To: <cctalk(a)classiccmp.org>
Sent: Friday, June 21, 2002 8:48 AM
Subject: RE: One SCSI tape connected to 2 hosts?
I guess I've abandoned the idea of hooking the
tape drive to both
systems. It sort of worked, but I found when I had it connected this
way, when backing up under Windows, the drive would suddenly become
unavailable. Sometimes it would run for an hour, and then this would
happen. I don't know if the VMS system was sending it a reset, or what.
I didn't use it enough under VMS to know if Windows was interfering from
that side, but I did a few medium length tests and it seemed to be OK.
I'll just throw the DDS-2 drive into the MicroVAX (I might have to use
some sort of mickey-mouse mounting system if I can't find a mounting
bracket for a BA42B case) and find another drive for the PC.
- Bob
-----Original Message-----
From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]
On Behalf Of Huw Davies
Sent: Friday, June 21, 2002 10:12 AM
To: cctalk(a)classiccmp.org
Subject: Re: One SCSI tape connected to 2 hosts?
At 03:16 PM 16/06/2002 -0500, Doc wrote:
On Sun, 16 Jun 2002, Bob Lafleur wrote:
I've noticed that my MV3100's SCSI host
ID's are set to 6 - I
thought this odd, as host ID's are usually 7. Are all MV3100's set
to 6, or is mine unique? Anyway, I thought since my PC's host ID is
7, I could connect my SCSI tape drive to both systems. So I ran a
cable from one connector on the back to my PC, and a cable from the
other connector to my MV3100. I figure it's a properly terminated
chain, as each host controller is terminated (I know the PC is, I
assume the MV3100 is).
It *seems* to work OK. But can anyone tell me for sure if this is
"legal"? I'm sure I'm looking for trouble if I try to use the same
tape drive from both systems at the same time, but as long as I
don't do that, is this an okay setup? It would sure beat changing
cables every time I want to move the tape drive from one system to
the other.
Bob,
A few of the older SCSI "how-to" pages diagrammed just such a setup. I've never seen it done in real life, but it
always looked like a
reasonable idea to me, too.
I just found out, talking to my boss, that both native Solaris and
Veritas Volume manager support that type of configuration.
It's also relevant that you can run IP-over-SCSI between hosts, and
ISTR that the original Beowulf code provided just that for fast
intra-cluster communication.
Of course Digital (and Compaq) supported systems with shared SCSI
storage
under OpenVMS alpha - not surprisingly they were known as SCSI clusters.
You still needed ethernet for SCS traffic but it certainly worked.
Huw Davies | e-mail: Huw.Davies(a)kerberos.davies.net.au
| "If God had wanted soccer played in the
| air, the sky would be painted green"
16 Jun
16 Jun
2:52 p.m.
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 1165 bytes
Desc: not available
Url :
http://www.classiccmp.org/pipermail/cctalk/attachments/20020616/b5655025/at…
17 Jun
17 Jun
1:22 p.m.
At 10:52 PM 6/16/2002 -0400, you wrote:
>>>>
>Anyway, I thought since my PC's host ID is 7, I could connect my SCSI
>tape drive to both systems. So I ran a cable from one connector on the
>back to my PC, and a cable from the other connector to my MV3100. I
>figure it's a properly terminated chain, as each host controller is
>terminated (I know the PC is, I assume the MV3100 is).
>
>It *seems* to work OK. But can anyone tell me for sure if this is
>"legal"? I'm sure I'm looking for trouble if I try to use the same
tape
>drive from both systems at the same time
We used to share a SCSI 9-track tape between our two MicroVAXen,
it worked fine for the most part. It was differential SCSI, I expect that
was because the cables were pretty long.
GZ
7995
days inactive
8000
days old
9 comments
8 participants
participants (8)
-
bob_lafleur＠technologist.com -
carlos_murillo＠epm.net.co -
doc＠mdrconsult.com -
edick＠idcomm.com -
ghldbrd＠ccp.com -
Huw.Davies＠kerberos.davies.net.au -
vaxman＠earthlink.net -
zaft＠azstarnet.com