External SCSI tape drive on HP UX question....

[VINCENT SPURGEON]

HP N-Class 4000 running HPUX 11.0.
Differential SCSI (68pin high density) in slot 9; Hardware path is 1/4. SCSI-ID set to "3".

I am connecting an external single ended (centronics style) Seagate 8mm dat drive: STD68000N. (let's not get into the reasons why...)

This tape drive was working on a BSDi system from which it was removed.

I attempted to add the tape drive through SAM. It detected that the tape drivers where NOT installed, so I allowd SAM to regen the kernel then I followed the instructions from SAM and powered off machine, connected tape drive, and powered on machine. No problems.

Went back into SAM and the device did not show up.

When I 'ioscan', no tape drive:
# ioscan -H 1/4
H/W Path Class Description
================================================
1/4 ba Local PCI Bus Adapter (782)
1/4/0/0 ext_bus SCSI C875 Fast Wide Differential
1/4/0/0.7 target
1/4/0/0.7.0 ctl Initiator

Question: would it be possible that I need a differential to single-end cable. I seem to recall in my weak memory that I do. I assumed that the cable was that since it was working on another server, but I can't confirm if that 68pin scsi interface is diff or s/e.

If I do need such a cable, does anyone know the HP part number, or another source?

If no one thinks it's a cable issue... lead me in a different direction.

Thanks for all your help!!!

[Bill Hassell · Accepted solution]

Fast Wide Differential is a unique interaface whicdh is electrically incompatible with all other SCSI devices. It is unfortunately quite confusing as the Fast Wide Differential connector is identical to other SCSI standards which are single ended, low voltage, etc. The single ended connections can indeed be converted with a simple adapter but differential requires different voltages which cannot be passively converted.

[Carlos Fernandez Riera]

Your N server has a utra scsi where is usualy pluged a DDS and/or CDROM.

This channel is single_ended terminated so you can plug your tape in this channel.

[VINCENT SPURGEON]

I forgot all about my external CD rom drive... connected tape drive and ioscan'd... works great!