DLT Tapes

[CA1052040]

I've got a DLT70i tape drive that's been working with HP tapes C5141F. Retired the old tapes and bought new of the same part#. New tapes do not work (tried several). Verified firmware, HP diagnostics check out OK. Brought an old tape out of retirement (again, same part#) and it works. Any ideas on why new tapes wouldn't be compatible any more. They work with my DLT80i device but not the 70i's.

[CA1052040]

Looks like it's the tape mfg. The tapes that work are HP # C5141F but mfg by Maxell. The ones that don't are the same part # but made by Fuji. Ink stamping on the back of the actual tape has either a "M" or "F" which designates mfg. I've ordered Maxell brand tapes....

[CA713937]

Don't blame the tape mfg.

Each media vendor tape has slightly different physical characteristics. It is therefore possible that the tape drive head can contour to a specific brand of media, and develop an error rate sensitivity to other vendor's media. This is similar to DDS drives that are used predominantly with one particular tape length, and then have error rate issues on other length (actually thickness) tapes. Note that HP DLT media is sourced from multiple suppliers.

Here's a related posting: http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=54369

Although I'd say it's more likely the tape compliance (e.g. stiffness) that impacts this the most.

[CA1052040]

Checked all tapes that I've ever had to fail (never worked) and they were mfg by Fuji. HP shouldn't market them as C5141F if not fully compatible. I work in the mfg business and all of our parts have to be consistant with past production or we change the part number.

[CA713937]

As I mentioned, HP uses multiple vendors for sourcing DLT media. All of the media vendors we use meet the requirements for the DLT tape specification, but each can vary within that specification. In this case one vendor is probably closer to one end of the spec, and the other vendor is closer to the other. When a drive head wears significantly, it can become selective to one over the other.

The problem here is NOT the media. The drive head is worn to the point where it can no longer read/write tapes that meet the spec. You can squeeze some extra mileage out of the drive by selecting media it still works with.

If the drive is still in warranty, HP will replace the drive if it doesn't work with our branded media.

[Rothery Harris]

The new tapes could be within specification but have less 'margin' than the old Maxell brand. I would like to know if the drive gets through the initial calibration phase. If the tape head was that worn I would expect some problems here. This phase happens after the tape is physically loaded but before the drive is ready.
If these new tapes work on the DLT80 drive then they would seem in good order. A worn read/write head could well be the suspect here.

[CA1052040]

Warranty went out 3 months ago....just my luck. I had a TV get me like that one time....What's my best option- stick with DLT technology or move "up"?

[CA713937]

Even with a worn head, you can squeeze some more mileage out of the drive by using the brand of media it works best with (Maxell in your case).

You can see how well the drive works with a particular tape brand by using either the device performance test or the DLT acceptance test within HP L&TT. The DLT acceptance test will show the number of soft errors per GB. As the number of soft errors go up, the drive performance will go down. As long as the drive performance still meets your needs, and you are not getting any hard write errors, then I'd say keep using the drive.

[CA1052040]

Now I can't get consistant test results....tried to reapply firmware at the suggestion of HP support and it failed.

[CA1052040]

OK..go get the net !!

Replaced dlt70i drive with a dlt80i drive from another server and the 80i runs where the 70i was failing...not surprised. Just for the heck of it, I installed the 70i on the server that had the 80i and now it works too.

Not sure which side is up right now, but the tapes are working. Think I'll still look at a new external method...this is getting a little too shaky.

Thanks