New tape drive showing up as 1m - not 0m

[Dan DeHaan]

Hardware is L2000 with DDS3 tape drive. The original drive died and I've replaced with another. The new drive shows up as /dev/rmt/1m instead of 0m like it used to.

I'm not 100% sure that I replaced the SCSI cables on the same pins as the old drive. They pulled off before I got a good look at them. They are 2 connectors with 3 slots each.

Would wrong placement of the SCSI cables cause this? How should the cables be attached?

[Steven E. Protter]

Shalom,

No, the hardware instance was used and not cleaned up.

You can clean it up:

http://docs.vlas.co.uk/library2//HP//HP-UX_IO_change.pdf

Requires downtime.

SEP

[TTr]

Post the output of "ll /dev/rmt". You may be able to recreate the "0m" devices without downtime.

[Dan DeHaan]

Thands for the replies.

Here is the output:
0x054000 Mar 9 14:05 0m
0x054080 Dec 21 2004 0mb
0x054040 Dec 21 2004 0mn
0x0540c0 Dec 21 2004 0mnb
0x052000 Mar 10 13:04 1m
0x052080 Mar 10 13:04 1mb
0x052040 Mar 10 13:04 1mn
0x0520c0 Mar 10 14:09 1mnb
0x052000 Mar 10 13:04 c5t2d0BEST
0x052080 Mar 10 13:04 c5t2d0BESTb
0x052040 Mar 10 13:04 c5t2d0BESTn
0x0520c0 Mar 10 14:09 c5t2d0BESTnb
0x052001 Mar 10 13:04 c5t2d0DDS
0x052081 Mar 10 13:04 c5t2d0DDSb
0x052041 Mar 10 13:04 c5t2d0DDSn
0x0520c1 Mar 10 13:04 c5t2d0DDSnb
0x054000 Mar 9 14:05 c5t4d0BEST
0x054080 Dec 21 2004 c5t4d0BESTb
0x054040 Dec 21 2004 c5t4d0BESTn
0x0540c0 Dec 21 2004 c5t4d0BESTnb
0x054001 Dec 21 2004 c5t4d0DDS
0x054081 Dec 21 2004 c5t4d0DDSb
0x054041 Dec 21 2004 c5t4d0DDSn
0x0540c1 Dec 21 2004 c5t4d0DDSnb
0xfffffe Dec 21 2004 stape_config

Can I just remove the 0m files and link new ones to the 1m files?

[Steven Schweda]

> Can I just remove the 0m files and link new
> ones to the 1m files?

I know nothing, but I'd expect that to work.
I'd try it. But I'd also try to straighten
this stuff out the right way when I found out
how, and had an opportunity.

[Patrick Wallek · Accepted solution]

It appears to me that the SCSI IDs of the original drive and the replacement drive were different.

The original drive (0m & c5t4d0*) was SCSI ID 4 and the replacement drive (1m & c5t2d0*) is SCSI ID 2.

If you want to use the 0m device files, power off the new tape drive, set the SCSI ID to 4, and power it back on.

Then do an 'ioscan -fnC tape' and you will probably now see the drive using the 0m files (and it should show as CLAIMED).

You will probably also see a drive with the 1m device files showing NO_HW. This is expected since that drive isn't there any more.

That one could be removed with the rmsf command.

[TTr]

Creating links will work but it is not a clean solution. The real devices are the ones that look like cXtYd0BEST such as c5t4d0BEST and c5t2d0BEST. You can do what Patrick suggested but you can also do the following.

Delete all the 0m* and 1m* devices. Then recreate the 0m devices as device files (not soft or hard links) with the same major and minor number as the actual cXtYd0BEST device.

You can find out which device c5t4 or c5t2 is the tape drive by runniong the ioscan command.

Then create the 0m devices by using the mknod command.

cd /dev/rmt
mknod 0m c XX 0x05Y000
mknod 0mn c XX 0x05Y040
mknod 0mb c XX 0x05Y080
mknod 0mnb c XX 0x05Y0c0

where XX is the major number (you left it out in the "ll" listing) and Y is the SCSI ID in your case it is either 2 or 4 based on the ioscan listing. Then the 0m devices will be the same as the actual cXtYd0BEST device for your tape drive.

[Dan DeHaan]

Thank you all. I finally got brave, disconnected the scsi pin cable and set the scsi address with a jumper clip (old school). Works fine now.

[Steven Schweda]

> [...] They are 2 connectors with 3 slots
> each.

> [...] disconnected the scsi pin cable and
> set the scsi address with a jumper clip
> [...]

Ah. SCSI _ID_ cables, not SCSI _data_
cables. If you have the usual 2x3 header
arrangement, with two separate 1x3 cables,
then you have several opportunities for
problems. In my experience, one row (the
bottom?) is usually three ground pins. The
cable for that group often has only one wire,
or three black wires (but not always). The
other row has the usual 1-2-4 switch wires,
which you can get on either right or
backwards. If SCSI ID 1 comes out as 4 (but
2 is right), then flipping over that half
should help.

Wide SCSI, with four wires instead of three,
adds only a little more fun.

An ohmmeter (properly applied) can usually
identify the sets of three ground pins, on
either the device or the switch side.