Cannot Get AIT2 LVD To Work

[CHANGE USERNAME TO westes]

Our AIT2 HVD drives have been among the most reliable we have used. We
have used them both with differential SCSI controllers as well as HVD fibre
bridges, both with great success. In our test lab, where we have two
permanent test servers that have Adaptec 39160 LVD host adapters, I cannot
get AIT2 LVD to work at all.

On one of the two servers, the AIT2 LVD drives come up but any operation
against them in Backup Exec 9.1 gives a CRC error. I have tried different
cables, different terminators, and different settings for speed on the
39160, all with no effect. On the second server, I cannot even get the
drive to be *seen* on the LVD chain. We tried AIT2 LVD drives in Scalar
100 libraries, Scalar 1000 libraries, and stand alone AIT2 LVD drives, all
with the same result. Finally, ready to pull my hair out, I even tried to
put them behind an ADIC SNC 5101 fibre bridge, which works fantastically
well with LTO1 and LTO2 LVD tape drives, but the effect was similar. As
soon as you start to work with the drives, they simply disapper from Windows
Device Manager.

At this point I have been threw different cables, terminators, servers, host
adapters, fibre bridges, and of course different AIT2 LVD drives, and I just
cannot find any combination that works reliably. Is there a trick to
using an AIT2 LVD drive, and is there a short list of host adapters that
work well with these?

 

[David Hawkins]

You are mixing High Voltage Differential interface ( HVD) and Low Voltage
Differential interface (LVD) parts this may result in damage to the drive
and or the host adapter.
If the AIT-2 is the SDX-510C then it has a HVD interface and needs a VHD
host adapter and terminators, the Adaptec AHA-2944UW is a HVD host.
The Adaptec 39160 is a LVD host and should be used with the SDX-500C and
LVD terminators.
( Yes both LVD and HVD use the same connectors !)

There is a bit on the Adaptec's pages about this at
http://www.adaptec.com/worldwide/su...language=English+US&prodkey=differential_SCSI

Dave

 

[CHANGE USERNAME TO westes]

You are mixing High Voltage Differential interface ( HVD) and Low Voltage
Differential interface (LVD) parts this may result in damage to the drive
and or the host adapter.

Absolutely not. I am completely aware of the difference, and I would never
cross up the two. Three people have spent 20 hours on this now, and each
of us knows this lesson and cross checks each other on this specific issue.

I made the point about HVD because our early experience with AIT2 was
specific to that interface. But that was only background. We are
*migrating* *from* HVD to LVD, and of course each of these has a different
SCSI host adapter.

 

[David Hawkins]

Ops sorry missed the bit about LVD AIT-2 drives, was around 1am when I
posted !
Is it more than one drive you have ? I have used the AIT-1, AIT-2, AIT-3 and
S-AIT drives and never had that type of problem with them. Have to say never
used then with normal backup programs as use the drives for storing
telemetry data, but the drives can be seen and accessed under windows NT &
2000, also linux with no problems that I have seen.
Have also used a selection of Adaptec & Qlogic host adapters and they all
worked.
If you just have the one Sony AIT-2 it may be you just have a dead one, but
if you have more than one, all being dead would be very un-lucky. I can see
why you are ready to pull my hair out, not even seeing the drives percent on
the bus on one server sounds very odd. The enquiry done to find the target
type and capability is done in 8-bit mode at the slowest speed, so should
always work, only once the targets capability is established does the
initiator change to 16-bit etc.

Dave