If the new drives support the multiple densities you can define the
     device class as format=drive and adsm should write at the highest
     density available on the drive.  IF YOU LEAVE A MIXTURE OF DRIVES DO
     NOT SPECIFY DRIVE (see the "Attention" in the adsm admin reference
     under define devclass)
     The drives should read (if the drive hardware allows) the tapes at the
     density at which they were written.
     To eliminate potential problems you might want to mark any filling
     volumes as readonly and let it just pickup with fresh scratch volumes
     for the higher density writes.  Normal expiration and reclamation
     should catch all volumes with a "full" status but the "filling"
     volumes that you mark "readonly" you would have to perform a "move
     data" against in order to clear them.

     hope this helps,
                     later,
                           Dwight


______________________________ Reply Separator _________________________________
Subject: Upgrading to DLT 7000s Tape Drives from DLT 4000s
Author:  Guy.LaCreta (Guy_LaCreta AT mckinsey DOT com) at unix,mime
Date:    7/20/98 3:08 PM


Hi ADSMers,

We are thinking about upgrading to DLT 7000  (7K) Tape Drives from DLT
4000s (4K).

We are using ADSM ver. 3.1 and ACSLS ver 5.2 on a RS/6000 running AIX
4.2.1.

The tape silo we have is a Storage Tek 9710.

Q1. Does anyone have an experience upgrading 4K tape drives to 7Ks with
ADSM?

Q2. Can you continue operating without making any additional changes to the
software other then device drivers, etc.?

Q3. Are the tapes created using the 4Ks  read/write reliable with the 7Ks?
(Supposed to be; experience?)

Q4. Do the tapes created by 4Ks remain in 4K format or do they migrate to
7K format?

Q5. Can the 4K created tapes be migrated to 7K format?

Q6. Is there any problem having both 4K created tapes and 7K created tapes
in the same library?

Q7. When you are reading or writting to a 4K created tape  on 7K drives is
there any performance degradation
        as opposed to reading or writting a 4K created tape on a 4K drive?

Thanks for your help.

Guy