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Jamaica module question

Barry Callahan_1
Occasional Visitor

Jamaica module question

I have a Jamaica A3311A disk array fully populated with 2.0GB HVD (DF) disks.

If I hang the array off a HVD controller, everything is hunky-dory.

I pulled out all the disk modules and swapped the drive in one of them with a known good LVD drive and reinserted that one module, changed the terminator I had on the array from HVD to LVD, and attached the array to a known good LVD controller, and no joy. The controller cannot see the drive.

Apparently, there is something about the board which goes between the SCA connector on the drive to the external connector of the module which is quintissentially HVD/DF.

My questions are as follows:
1) Is my above assumption correct?

2) If so, could someone point me to some info on why? I thought all the connector board had to do was simply pass through all the signal and power lines.

3) Does anyone know of a way to get my existing DF drive encloures to be happy with LVD or SE drives? Or could anyone tell me of a reasonably priced source for empty SE disk modules?

Thanks.

Barry
10 REPLIES
harry d brown jr
Honored Contributor

Re: Jamaica module question


Mixing hvd and lvd might/can damage your equipment.

http://www.storagesearch.com/lvdart.html


live free or die
harry
Live Free or Die
Barry Callahan_1
Occasional Visitor

Re: Jamaica module question

RE: HVD and LVD being incompatable

I knew that already. Short-term, the entire bus shuts down. If left on for more than a couple minutes, damage is possible...

But what I'm trying to do is not use HVD drives on an LVD controller, or vice-versa.

Allow me to restate my original query:

I have modules for the Jamaica which originally contained HVD drives.
I opened the modules, and replaced the drives with higher capacity LVD ones, and then attached the array to an LVD controller, and it doesn't work.

Can someone explain why?

All hardware involved has been tested and is known good.
harry d brown jr
Honored Contributor

Re: Jamaica module question

From the previous link:

There is no more direct compatibility between LVD and HVD SCSI than there is between HVD and SE SCSI. It does not exist. Placing an LVD device on an HVD bus will cause the LVD device to shut down. Placing an HVD device on an LVD bus will cause the entire LVD bus to shut down.

For info on the HASS rack:
http://www.hp.com/cposupport/manual_set/lpg28396.pdf
http://www.hp.com/products1/mpeixservers/info_library/config_order/config/5243046c.pdf


live free or die
harry

Live Free or Die
Barry Callahan_1
Occasional Visitor

Re: Jamaica module question

So far, you've pointed out the following facts, which I was already aware of:

1) HVD and LVD don't mix.
I understand that if I attach an HVD device to a SCSI bus, every LVD device on that bus will shut down. From what I've been told elsewhere, SE devices don't know to shut down in the presence of an HVD device, and can be damaged by being on the same bus as the HVD device.

2) HP never shipped any LVD disk modules for the Jamaica. However, they DID ship SE modules. If the array is populated only with SE modules, you should be able to hang the array from an LVD controller - the controller and all other LVD devices on that SCSI bus will switch to SE mode.

Here's the root of my confusion:
If the controller is LVD, the terminator is LVD, and every disk in every module that's installed in the array is LVD, (remember, I replaced all the HVD drives in the modules I have with LVD ones) and the above mentioned terminator, controller, and array are the only things on the bus, where's the HVD device?

If I take an HVD and SE module for the Jamaica, put them side-by-side, open them up, remove the drives and scrape off the labels from the front and bottom of the modules, is there still something different about them?
Mike Still
Occasional Advisor

Re: Jamaica module question

Ok you took apart one of your HVD drives and replaced it with a new LVD drive?

If so, then did the little ribbon connecting from the SCA to the big drive connector have some chips on it? If it did then that's what converts to HVD and you won't be successful. See HP really put SE drives in those canisters and used a converter to get HVD.

If your cable doesn't have any chips in it then you really did have an HVD drive and it was straight through. In that case I don't see why it wouldn't work as long as you put a LVD terminator on the outside.

Technically I could be wrong, but after taking a couple of these apart this is what I figure.
Vincent Farrugia
Honored Contributor

Re: Jamaica module question

Hello,

The internal SCSI controller of your HASS array is HVD, so you cannot give him LVD drives from an LVD HBA and hope it will work. If you give him SE drives, you have a good probability of it working. They used to come either as SE or DIFF drives.

HTH,
Vince
Tape Drives RULE!!!
Stefan Saliba
Trusted Contributor

Re: Jamaica module question

YOU SAID
""
If I take an HVD and SE module for the Jamaica, put them side-by-side, open them up, remove the drives and scrape off the labels from the front and bottom of the modules, is there still something different about them? ""


Indeed there is. The SE and DF modules have a small circuit at the back which is different. I have an SE module for an Autoraid which is similiar to a Jamaica. Internally it has an LVD disk and works fine. I checked the module with DF one and it is different.

You need either get larger HVD drives or get SE modules and put in LVD drives.

PLease note that even though you will hook LVD drives you will still get SE speeds.

Good Luck

Stefan
Joaquin Gil de Vergara
Respected Contributor

Re: Jamaica module question

Barry

In a Jamaica box you can put only DF(HVD) or SE disks (the bus is DF/HVD)

You can mix disk DF and SE but then the entire bus will be SE (be carefull with SCSI IDs SE only supports 8 devices)

You can`t put an LVD disk in the Jamaica, althought you connect to an LVD card
Teach is the best way to learn
guest_1
Occasional Visitor

Re: Jamaica module question

It is possible in my experience to use
SE disks (U160 or U320) in Jamaicas:

For that you open the black disk box
of a 4.3GB DF or greater disk sizes.

Check the printed circuit board and
flexible connector. The flexible connector
should have crossed circuits, not parallel.
The printed board should be green, not
brown, and have 3 chips going across the printed circuit lines, plus small chips
on the sides, including something that
looks like a 20MHz oscillator.

2GB disks have a yellow/brown circuit
with DF printed on it (or SE if single
ended) and won't work.

doing that switch can actually damage
the Jamaica enclosure.

To be on the safe side, check the
model of the hard disk, usually Seagate
like ST39173WC.

N: Narrow
W: SE
WD: HVD
LW: LVD
WC: SE
LC: LVD

NOTE: the Jamaica will still run as a DF
enclosure.
Zygmunt Krawczyk
Honored Contributor

Re: Jamaica module question

Hi,

if you have original 2GB HVD (DF) disk for Jamaica, you have the HVD disk inside and pass-through adapter without chips. I think it is passive adapter. Try to replace disk with LVD drive and set up jumper on drive to force SE mode. Next connect SE HDTS68 terminator (HP C2972A) at the back of Jamaica and connect it to LVD controller. The controller should switch to SE mode.

Regards,
Zygmunt