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Clening DLT8000

Jorgen_2
Occasional Contributor

Clening DLT8000

Hi
Im intrested to know exactly where and how the cleaning procedur works, from where, and how it initiates...some webpages....

 

 

P.S. This thread has been moved from Automated Backup to Tape Libraries and Drives - HP Forums Moderator

Jorgen Krantz
3 REPLIES
CA713937
Honored Contributor

Re: Clening DLT8000


I'm not aware of any good web pages that answer all of your questions. You can find bits and pieces answered in FAQs and other forum postings. Here's a (very basic) starter: http://www.hp.com/products1/storage/media/tapebackup_media/tape_dlt/faqs_print.html

Now here's my explanation:

* Clean the drive only when it requests it. Over-cleaning can wear down the head. One pass of the cleaning tape is roughly equivalent to 20 hours of tape motion.

* The DLT cleaning tape is good for 20 uses. After 20 uses, the tape will load, but will not do any cleaning. On libraries, they generally tell you the cleaning tape is expired. On a standalone drive, the cleaning light just stays on.

* A DLT cleaning tape is raw DLT media, which has not been burnished (i.e. polished). It is more abrasive, and is specifically designed to remove staining off the head. It is less effective at removing contamination.

* If a drive has a persistent cleaning light (which will not go away with a single use of a cleaning tape), then use a new cleaning tape, and clean the drive up to three times (or until the cleaning light goes away). It is possible that the drive has some contamination (e.g. smoke, dust, ash, paper fiber, carpet fiber, etc), and the cleaning tape itself may get contaminated.

* The drive doesn't actually sense that the head is dirty. The cleaning light is only an indication that the read/write error rate has dropped, or the drive has encountered a hard read/write error. If cleaning lights reoccur, see if you can isolate it to a particular tape, and then remove that tape from your rotation.

* The DLT drive is designed to be self-cleaning, if used in a clean environment, with quality media, and if the drive is generally streaming. Cleaning lights occur more often if the drive is not streaming (i.e. repositioning frequently).

* Make sure your tapes are stored in a clean environment, and are conditioned to the room for at least 24 hours before use. Ideally the room (and storage area) should be 64-79F, and 40-60%RH. If the drive is operated in a very dry or very humid environment, cleaning lights will occur more often.

* Note that DLT and DLT1 drives use a different cleaning tape, so make sure you buy the right ones.

* Lately, use the latest version of drive firmware, as there have been a number of improvements around cleaning light behavior. For an HP standalone drive, V80 is current, and for an HP library drive, V59 is current (for DLT8000s) as of March 2002.
The journey IS the reward.
Jorgen_2
Occasional Contributor

Re: Clening DLT8000

Thank??s David, that??s a good answer so far!
That i really want to know is, where,what and when the signal that says "turn cleaning lamp on" and so on.....
Jorgen Krantz
CA713937
Honored Contributor

Re: Clening DLT8000


> That i really want to know is, where,what and when the signal that says "turn cleaning lamp on" and so on.....

I think I partially answered that above. I said:

* The drive doesn't actually sense that the head is dirty. The cleaning light is only an indication that the read/write error rate has dropped, or the drive has encountered a hard read/write error.

I'll give you more details. The drive can turn on the cleaning light when:

1) The amount of corrected read/write failures goes beyond a certain threshold.

2) The drive encounters a hard error during the calibration of tape (during loading).

3) The drive encounters an unrecoverable (hard) read/write error.

Note: The drive will turn the cleaning light off after a cleaning operation had been performed, or another tape is loaded which the drive can successfully load and calibrate with an acceptable soft error rate.

To add to the confusion, the drive has three different ways to communicate cleaning light conditions to the host. Two are recovered errors, 'soft error exceeds threshold' and 'cleaning requested', and one is an unrecovered error 'cleaning required'.

The 'cleaning required' condition is also sent to the host using 'TapeAlerts'.

The exact thresholds and algorithms vary somewhat by DLT drive type, and by code version.

I already mentioned how to avoid cleaning lights, but I'll summarize.
1) Use good quality media.
2) Store the media properly.
3) Acclimate the media.
4) Use within the recommended temp/humidity range.
5) Avoid environmental contamination (dust, ash, smoke, paper/carpet fiber, etc).
6) Keep the drive streaming.
The journey IS the reward.