External SCSI Disc

[MarkSyder]

Hi everybody,

I am trying to attach an external single-ended SCSI disc to an HP-UX 11i system.

I have tried the disc on my own (10.20) workstation and confirmed that it is in good working order, but when I attach it to the server SAM reports that it cannot see any discs, including the ones that are already on the system.

The SCSI port is definitely good: it usually has a tape drive attached to it. The cable is also good: it is the same cable I use to attach the tape drive. The cables I used to attach the disc to my workstation and to the server both say SCSI 2 on them, so I would conclude that the cable is compatible. The same terminator was in the disc when it was attached to my workstation and to the server.

The device numbers of the discs already on the system are 0, 8, and 15 (15 being the root disc). I would not have expected a conflict of device IDs, because I am putting the new disc on a separate SCSI bus. I gave the disc a device id of 5.

Any ideas?

Mark Syder (like the drink but spelt different)

[Jeff Schussele]

Hi Mark,

To what type SCSI HBA are you attaching this disk?
If it's not an LVD/SE, but a HVD, then it won't work & could possibly damage the drive.
Verify your SCSI card type.

Rgds,
Jeff Schussele (Like nothing & spelt funny)

[MarkSyder]

Thanks Jeff.

The wording under the port is "Narrow single-ended SCSI". It's a 50-pin port being attached to a 68-pin port on the disc.

According to HP's forum guidelines, your answer should receive 3 points, but I'm giving you an extra 3 for your emulation of my signature! Everyone else please note - I'm only doing this once!

Mark

[Steven E. Protter]

After connecting the drive to the second system:

ioscan -fnC disk
insf -e

This should be fine.

SEP

[Jeff Schussele]

Alright - let's verify what - if anything is attached to this HBA.
Run the following:

ioscan -fnC ext-bus

verify via the HW address that it's indeed a SE & not an HVD.

Then run

ioscan -fnC ctl

and verify via the HW address again the controllers SCSI ID - should be 7, but could have been set to something else.

Then finally run

ioscan -fnC target | more

And verify that nothing else is on the bus as you imply. The HW path will give you the SCSI ID.

HTH,
Jeff

[doug mielke]

Narrow vs wide?
SCSI3 (wide) seems to be all the rage now, and that could be what's in the 11i server. I don't think there's a way to make narrow run on wide via cable adapters.

I'd try to confirm scsi format compatability between drive and server card.


And remember, the very best thing about standards is......

there are so many to choose from.

[John Dvorchak]

I believe that you answered your own question. You state that it is a "single ended" disk and yet you are plugging it into a wide scsi adapter. That won't work, as you are finding out. I am afraid that in order to use your "external disk" you must have a single ended SCSI adapter in the server.

Sorry,
John

[Bill Hassell]

What server are you using? HP adopted the FWD-HV standard (FastWideDifferential-HighVoltage) many years ago and it was the only SCSI interface that could run on 75 foot cables. However, unlike all previous (and subsequent) standards, the voltage was much higher and completely incompatible. That means that a simple cable cannot translate the signals. There were FWD-HV disks as well as tapes and for servers like the K-series, all internal disks were FWD-HV except the CDROM and internal tape drive. This can be seen from an ioscan:

ioscan -kfH 10/12

On your server, substitute the path to the I/O cards. The 15 address for the internal disk also says "differential" so unless this is a very recent server (like the rp-series) it is likely a FWD-HV interface.

[Jeff Schussele]

Hi John,

Believe it's the other way around. He states it's a narrow SE HBA & that the drive has a 68-pin connector - which implies it's a wide-drive. I *think* that will work as long as he keeps the ID at 7 or less & doesn't conflict with any other ID on the bus.
The only thing I'm not sure of is the whether both ends are LVD equivalent and properly terminated.

Mark - What's the *exact* make & model on that disk?

Rgds,
Jeff

[MarkSyder]

Hi everybody,

Nice to see so many replies waiting for me this morning.

To answer your points in turn:

SEP - I will try that on Friday afternoon (the first chance I will have to stay behind after the users have gone home).

Jeff - ioscan -fnC ext-bus returns the root prompt without any output. SAM shows the card as 0/0/2/0 c720 SCSI C87x Fast Wide Single-Ended and the initiator as
0/0/2/0.7.0 - this is definitely the correct card as the tape shows up on this bus.

ioscan -fnC ctl
Class I H/W Path Driver S/W State H/W Type Description
=====================================================================
ctl 0 0/0/1/0.7.0 sctl CLAIMED DEVICE Initiator
/dev/rscsi/c0t7d0
ctl 4 0/0/1/0.14.0 sctl CLAIMED DEVICE HP A5272A
/dev/rscsi/c0t14d0
ctl 1 0/0/1/1.7.0 sctl CLAIMED DEVICE Initiator
/dev/rscsi/c1t7d0
ctl 2 0/0/2/0.7.0 sctl CLAIMED DEVICE Initiator
/dev/rscsi/c2t7d0
ctl 3 0/0/2/1.7.0 sctl CLAIMED DEVICE Initiator
/dev/rscsi/c3t7d0

ioscan -fnC target|pg
Class I H/W Path Driver S/W State H/W Type Description
===================================================================
target 0 0/0/1/0.0 tgt CLAIMED DEVICE
target 1 0/0/1/0.7 tgt CLAIMED DEVICE
target 2 0/0/1/0.8 tgt CLAIMED DEVICE
target 3 0/0/1/0.14 tgt CLAIMED DEVICE
target 4 0/0/1/1.7 tgt CLAIMED DEVICE
target 5 0/0/1/1.15 tgt CLAIMED DEVICE
target 6 0/0/2/0.3 tgt CLAIMED DEVICE
target 7 0/0/2/0.7 tgt CLAIMED DEVICE
target 8 0/0/2/1.7 tgt CLAIMED DEVICE

I think I'll leave it there before this post becomes too large and unwieldy. I'll send a separate post answering everyone else.

Mark

[MarkSyder]

As promised, a separate posting replying to everyone else.

Doug and John - the port on the server is narrow, the port on the disc is wide. I have a cable which is narrow at one end and wide at the other. The disc works on my workstation using this cable.

Bill - the bus with the internal discs shows as ultra-wide LVD.

Jeff - The disc is a Seagate. I will check the exact model if I am able to shut down my workstation some time today and attach it.

Thanks to everyone for their replies.

Mark

[Craig Smith_13]

I believe Seagate drives sense the bus type (narrow vs wide), so that shouldn't be a problem, however try taking the external terminator off, it may have internal termination already (power off the drive, remove terminator, power back on, try ioscan again).

[MarkSyder]

Thanks Craig.

I'm pretty certain we aren't using an internal terminator, as the tape drive always has an external terminator in place.

No chance to shut my workstation down today to check the model of drive - it's been a busy day!

Mark

[MarkSyder]

Craig - I've just realized you were talking about the disc drive having internal termination, not the SCSI bus!

If I decide your posting should have got more than the 3 points I've just given you, I'll ask you to post another entry so I can add to them.

Mark

[MarkSyder]

Jeff,

The disc is a Seagate ST336607LW.

Mark

[Jeff Schussele]

OK - looking at the specs page on this

http://www.seagate.com/support/disc/specs/scsi/st336607lw.html

I see that it's a Ultra320 SCSI wide LVD drive.
And I also find this note:

Note: LW and LC drives do not have internal terminators or
any other way of adding internal terminators to the
drive; use external active termination if required.
Use active (ANSI SCSI-2 Alternative 2) terminators
when terminating the bus. Use active negation
terminators when terminating a SCSI Ultra2 bus
operating in Low Voltage Differential (LVD) mode.

So it appears you'll have to terminate the bus externally and note the termination types requirements for the diff bus types.

Also on the config page:

http://www.seagate.com/support/disc/scsi/st336607lw.html

I see on the Option select jumpers that it has a jumper for "Force single-ended bus mode". And "Term. power to SCSI bus".

So it appears that if you satisfy these requirements, you should be able to get this thing running, although on the type bus your hanging it, you won't get the best performance out of this drive. For that you'd need a newer Ultra320 HBA.

HTH,
Jeff