Re: Tape Cleaning

      Correct, actually there was a time when the ATL would interrupt
     normal processing, when it called for a drive cleaning, and an adsm
     task would blow up/off 'cause it was looking for a scratch tape (or
     specific volser) and when the cleaning tape was mounted everything
     went sour.


______________________________ Reply Separator _________________________________
Subject: Re: Tape Cleaning
Author:  PrathW1 (PrathW1 AT central.ssd.jhuapl DOT edu) at unix,mime
Date:    8/5/98 9:14 AM


I don't think ADSM is aware of any type of tape cleaning.

Many robotic libraries handle cleaning outboard.
If the drive wants to be cleaned, it sends a signal to the tape robot, which
mounts the cleaning tape AFTER the current tape is dismounted.

If ADSM has a reason to send the robot or drive commands while the drive is
being cleaned, those commands are just delayed a bit until the cleaning tape
is dismounted and the drive is free again.

I know this is the way cleaning works on the IBM3575, and on the STK9710.

The drawback to this scheme, using DLT tape drives, is that you will only get
a "cleaning required" on the tape drive when the drive detects a degradation
in signal strength; but the robot can't mount the cleaning tape until the
current tape is dismounted.   As a result, we frequently see many many bogus
I/O errors when ADSM is trying to read a tape.  "Bogus", in the sense that
there is nothing wrong with the tape, the drive just needs to be cleaned, but
it can't be cleaned until ADSM fails the current tape operation and dismounts
the tape.  Very inconvenient.

For any other robotic tape device, you just have to find out how the vendor
handles it.  It varies a lot from vendor to vendor.

Hope this helps.

===============================================================
Wanda Prather
Johns Hopkins Applied Physics Lab
443-778-8769
wanda_prather AT jhuapl DOT edu

"Intelligence has much less practical application than you'd think."
              - Scott Adams/Dilbert
===============================================================


> ----------
> From:         malkit[SMTP:malkit AT udi.co DOT il]
> Sent:         Wednesday, July 29, 1998 5:00 PM
> To:   ADSM-L AT vm.marist DOT edu
> Subject:      Tape Cleaning
>
> Hello !
>
> Where can I get the information about what libraries support auto
> cleaning with ADSM ?
> How do you all manage to do tape cleaning ? What about IBM DLT- Is there
> a way for auto cleaning ?
>
> Regards
> --
> Malkit Hayun, UDI
> Application Engineer
> Office:  972-3-9233440
> Mobile: 972-52-834575
> Email: malkit AT udi.co DOT il
>