SUMMARY: Control of DLT changer

From: Graham Allan <ALLAN_at_mnhep1.hep.umn.edu>
Date: Fri, 11 Dec 1998 17:16:43 -0600

Sorry for the delay in summary; despite the helpful replies, it still
took a little while to get things working.

My original question was:

I want to control a DLT changer from Digital UNIX 4.0D.

  The unit in question is an Overland Data LoaderXpress LXL4110, which I
  am assured by the vendor is controllable by Digital UNIX. My question is
  simply: how? I would imagine one has to install the SCSI CAM layered
  product and use the Medium Changer software. Can anyone give hints on
  how to configure this software appropriately, since in its raw state it
  seems to only understand Digital tape drives plus a few other models? I
  will be using this drive only with standard vdump and similar commands -
  I will not be using Legato or Networker or other such packages.

Indeed, the CLC MEdia Changer does control the loader just fine. At
first, it didn't, but it turned out that the loader had been switched to
sequential mode, rather than random access. This caused the changer
commands to return an unhelpful i/o error, so unfortunately it took me
some time to realise what the problem was.

Thanks for the following replies:

From: alan_at_nabeth.cxo.dec.com

        The CLC Media Changer driver is a licensed part of the
        system that you shouldn't be using if you don't have
        a license for it. You can't buy the license directly
        and have to buy one of the products that uses it. The
        least expensive of these is the Media Robot Utility
        which is also easier to setup and run than mcutil of
        the CLC kit.

        Unfortunately, MRU has never qualified a native Overland
        loader so we can't make any guarantee that it will work.
        We do support the TL891 which is a repackaged version of
        their 10 slot DLT library and the TKZ62 and TKZ64 which
        are 10 and 60 slot versions of the 3480 compatible loaders.

We do have these licenses via ESL/CSLG. I may look at MRU in future; I
simply couldn't see it on the CDs available to me so chose the CSC
product instead.

From: Jason Orendorf <orendorf_at_alf.dec.com>

  Hi Graham. To use the changer you'll need several things:
  1. Install SCSI CAM Layered Components version 3.1C (313) to
     get the drives for media changer devices.
  2. Install Media Robot Utility (MRU) to control the changer
     mechanism.
  3. Since this is a third party device, you'll likely need to obtain
     a DDR entry from the vendor (roughly equivalent to a cam_data.c
     entry used in Digital UNIX 3.X).

  Note that it will be difficult to use the changer seamlessly
  without software such as NSR. MRU allows you to change tapes
  and such but must be done explicitly. Tools like vdump, tar, etc.
  won't be able to perform unattended backups which span tapes (when
  these tools reach End-Of-Tape they stop and wait for the operator
  to tell the utility to continue) so you'll have to manually
  divide your backups into what will fit on one tape - or physically
  be present to change the tape. NSR deals with tape spanning
  itself so you don't have to.

  You could work around this problem with a scripting language like
  expect but this would require knowledge of that language.
Received on Fri Dec 11 1998 - 23:18:42 NZDT

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