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K570 server can't see Quantum tape library

Edmund_2
Advisor

K570 server can't see Quantum tape library

Hi all,

I got a Quantum tape library 'ATL PowerStor L200' and the interface is SCSI SE 68pin. I connect it to the server's 68-pin SCSI DF ( unused channel without any device atached) but the server can't see (ioscan) the changer and the tape. I also try to connect it to the server core IO SCSI port. But the internal hard disks are gone when I reboot. Should I use 50pin-to-68pin SCSI cable to connect the library to the server's 50pin SCSI SE port? Or this model just doesn't work with my server.

Thanks

Edmund
11 REPLIES
Alexander M. Ermes
Honored Contributor

Re: K570 server can't see Quantum tape library

Hi there.
Try the 50 to 68 pin cable.
We have a Quantum DLT4500S here and use the same cable.
Rgds
Alexander M. Ermes
.. and all these memories are going to vanish like tears in the rain! final words from Rutger Hauer in "Blade Runner"
Vincent Farrugia
Honored Contributor

Re: K570 server can't see Quantum tape library

Hello,

When I entered Quantum's site, this seemed very much like the 1/20 Autoloader by HP. Also, you can have LVD or HVD drives with this model. If you are connecting to a K-Class server, make sure that the drive in question is HVD, otherwise it just won't work, unless you put an LVD-to-HVd converter in between.

HTH,
Vince
Tape Drives RULE!!!
Dirk Wiedemann
Respected Contributor

Re: K570 server can't see Quantum tape library

Hi,

you can't connect a single ended (SE) device to a differential SCSI controller. Though they use malicious the same connectors, they are incompatibel. Be careful, in worst case connecting the wrong devices to a controller can damage the device or the controller.
Your only chance is the 50 pin SE-controller with the spoken to cable. Their is a good chance. But notice that SE-cables have to be shorter than differential. If you conectet up to three devices (intern AND extern), the whole cable may max. 3 m long (also intern AND extern), if you connect more than three dev the max length of the whole cable shouldn't be longer than 1,5 m. Don't forget a convenient terminator on both sides of the bus.
Dirk
Edmund_2
Advisor

Re: K570 server can't see Quantum tape library

The tape library labels the port 'SE' so I believe it should be a SE, not HV/LV DF interface.

Some SCSI related web sites mentions that if SE device is connected to a DF SCSI bus with other DF devices, all devices would automatically run as SE without problem. They are compatible. Only HV and LV are not compatible. Is this correct?

Okay. Seems I need to get the cable to see whether it works or not.

Thanks all

Edmund
Dietmar Konermann
Honored Contributor

Re: K570 server can't see Quantum tape library

Hi, Edmund!

Low voltage differential (LVD) interfaces are usually able to switch to single ended (SE) operation. But there is no guarantee an LVD device will be able to do so also.

Your 68pin interfaces in the K-Class should be high voltage differential (HVD)... they are not compatible. Neither with LVD nor with SE.

Regards...
Dietmar.
"Logic is the beginning of wisdom; not the end." -- Spock (Star Trek VI: The Undiscovered Country)
Dirk Wiedemann
Respected Contributor

Re: K570 server can't see Quantum tape library

Hi again,

contrary to SE the differential (HV) use two wire for each signal (D+ and D-). That means, on HV-differential you have a completely different pin assignment.
Hig voltage differential (HVD) is incompatibel to single ended and low voltage differential (LVD).
HVD works with +/- 1,5 volt, LVD (aka Ultra2) with +/- 60 mV. This allows longer cable up to 12 m and a faster transfer up to 80 MB/sec.
LVD is a special case. Like HVD it use two wire for each signal (D+ and D-). By a clever interface it is possible to combine HVD- and SE-devices (look at the attachement). So you are able to connect a SE-device on a LVD bus. But notice: only if you use exclusively LVD-devices you will get the advantages of LVD.

regards
Dirk
Vincent Farrugia
Honored Contributor

Re: K570 server can't see Quantum tape library

Hello,

Could you tell us what is the tape drive in your autoloader?

Vince
Tape Drives RULE!!!
Edmund_2
Advisor

Re: K570 server can't see Quantum tape library

Hi Vince,

When I searched Quantum web site, I found that only DLT7000 model has SE interface. The others support either HVD or LVD. So I assume that it should be a DLT7000.

As I got this tape without manual/guide and I am not familiar with this kind of backup device, I can't tell u firmly.

Thx.

Edmund
Rothery Harris
Trusted Contributor

Re: K570 server can't see Quantum tape library

Dear Edmund,
The HP9000 K-class has only 68 pin fast wide high voltage differential SCSI and 50 pin narrow single-ended SCSI.
DLT7000 drives can be in several flavours depending on the OEM version. You really need to identify the model.
Regards

Rothery
Michael Lampi
Trusted Contributor

Re: K570 server can't see Quantum tape library

Very simple solution. Use the 50 pin to 68 pin SCSI converter cable to connect to the server's 50 pin SCSI SE port.

The SCSI SE 68 pin port of your library is absolutely not electrically compatible with the server's SCSI DF port.

The only way to make the server's DF SCSI port is to use an external SCSI HVD to SE converter. This costs typically in the $400 to $500 range. However, this would be substantially higher performance (up to 20 MB/sec) than the SE 50 pin SCSI port, which is normally at most 5 MB/sec.

As an aside, LVD SCSI devices can be used on SE buses, but in doing so the device changes to operate in SE mode. This means that the highest data transfer rate drops to at most Ultra SCSI (40 MB/sec in wide mode), and the maximum cable length of 3 meters.
A journey of 1000 steps ends in a mile.
D. Jackson_1
Honored Contributor

Re: K570 server can't see Quantum tape library

Could it be that you need to terminate something??

Not sure - Just a thought.

Good Luck