SCSI-2 Tape unit on U320 adapter

[Craig Harvey_1]

Would there be any problem attaching a SCSI-2 tape drive (compaq 12/24 DAT) to a U320 adapter. It would be the only device and the tape uint has a 50 to 68 pin converter.

[David Ruska]

Your product is likely to be Single-ended SCSI (SE). You should check with your HBA, but most U320 cards (and those from Adaptec) state support for SE devices.

You should not mix LVD with SE devices on the same bus (since the who bus will be running the slower SE speeds).

You will also need an SE or LVD/SE auto-sensing terminator.

[Craig Harvey_1]

The card is an lsi20320-hp. I couldn't find anything that said one way or the other on the HP tech specs. Maybe I just don't know where to look.

If I were to attach a SE device to a adapter that is unable to support it (or use an incorrect termination) would it simply not report that there are devices attached or is there substantial risk that it would damage either the device or adapter?

[David Ruska]

The data sheet for the LSI20320-R (http://www.lsilogic.com/files/docs/marketing_docs/storage_stand_prod/habs/lsi20320pb.pdf) says:
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SCSI Bus: Ultra320, LVD (Low Voltage Differential) and Ultra Wide SE (Single-Ended)

Termination: Universal (LVD/SE) termination, auto cable detection
---

So it does support SE devices.

You need to provide appropriate termination on the device end, and convert from a wide to a narrow cable.

If you don't have the proper termination, usually the devices are not discovered, or you get I/O errors. It should not cause physical damage.

[Craig Harvey_1]

Clearly not the same card but close enough I will assume.

Thanks