Mailinglist Archive: opensuse (1264 mails)

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Re: [opensuse] Tape Drive Trouble
On 20/06/17 20:58, Wols Lists wrote:
On 20/06/17 20:23, Paul Groves wrote:
On 20/06/17 19:47, John Andersen wrote:
On 06/20/2017 11:43 AM, Paul Groves wrote:
I assume if I remove the pin from the last drive it will act as a
built in terminator?
No, that term power just supplies power for the terminator to use to
sense if the
cable has any devices installed. AFAIR, you only need ONE unit to
supply term power
and it doesn't matter which one, and having more than one unit
supplying term power is
perfectly fine.

Termination via onboard termination resistors is a different thing.

You learn something new every day! Thanks for that.

I am not sure if the terminator is at fault. I only have the one.
If it is the terminator surely it would always be the last drive with
the problem? When I connect my LTO2 drive here it works fine.

NO NO NO.

My memory of SCSI is patchy, but poor termination messes up the entire
cable. Termination is supposed to provide a stable 5V/0V signalling
channel or something like that. If the cable isn't properly terminated
you get crosstalk, floating voltages, interference - the whole gamut of
electrical misbehaviour.

Cheers,
Wolt
OK makes sense to me. I suppose then I should check the voltages on the bus and also take out the cable and check for damage or unusually high resistance on the cores.

Where can anyone even buy SCSI cables and terminators now? Ebay perhaps. It might be a good idea to try a new terminator / cable anyway. I remember SCSI and PATA cables where you crimp your own connectors on. Haven't seen those for a good while now. If it is my cable I might get one of those so I can make the cable as short as possible to avoid unnecessary interference.

Saying all this though the other 3 drives operate fine.

One thing I noticed is that my SCSI controlled is 160MBps (the same as my DAT72 / LTO1 and LTO2 drives) but the LTO 3 and 4 drives (I am having problems with) are 320MBps. Could it be a compatibility issue perhaps? If I am correct though it should work fine but just at the lower speed.

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