See the Adsm Server PTF-12 README for instructions on configuring 3570 (just do
a search on that string).  Also, because of confusion, here are some additional
notes from the Now Available (Yeaaaaah!) PTF-13 readme:

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Additional notes about configuring 3570 with ADSM
********************************************************************
Physical Configuration of 3570 Model B02/B12 (Two drive models):
  These two drive models can be in either base or split mode. Split
  mode divides the library to look like 2 - 1 drive/10 cartridge
  libraries.  Base mode uses the 3570 as 1 - 2 drive/20 cartridge
  library.  For ADSM you don't want to use split mode because ADSM has
  functions that require 2 drives. Use base mode with ADSM.

 (This contradicts an earlier statement in the README which says you
can use split mode.  Split mode would only be used if you must
share the library from two separate hosts.  Base mode is strongly recommended
for use with ADSM because of the requirement that a library have two drives
to do volume reclaiming.)

  For BASE mode to work properly with ADSM, you need to first set the
  3570 box to BASE mode. The hardware cabling configuration for the BASE
  mode should have a single SCSI differential bus from your host to drive
  1. The SCSI Bus Jumper Cable (Part number 49G6456)
  is required and should be installed between the drive 1 and drive 2
  SCSI ports.  At port 2, it has to be terminated.

Physical Configuration of 3570 Model B01/B11 (One drive models):
  These models should be configured in Base mode.

The minimum code levels for ADSM support of 3570 is:
 3570 microcode: level 271 or above
 ADSM Server: PTF-11 or above
 Atape Device driver: 2.6.1.0 level or above

Both the one-drive and two-drive 3570 models must be further configured
to be in random mode or manual mode for the ADSM Server.  Manual mode
means a tape operator loads the tapes in the drives (no automated tape
loading). Random lets the library act like a full blown tape library.
Random mode is strongly recommended with ADSM.

The Magstar MP SCSI interface can be assigned a single SCSI-ID in the
range of 0 to 15, but must be the only device on the bus with that ID.

The Atape device driver level 2.6.1.0 (or later) is a PRE-REQUISITE for
users that have 3590-B11s or any model 3570.  Without this level, users
will see the following error message when bringing up the server:

    ANR9999D MMSSCSI.C (3633) UNSUPPORTED SCSI LIBRARY

To obtain this version of Atape:
  1) anonymous ftp to index.storsys.ibm.com
  2) cd to /devdrvr/AIX.
  3) issue the commands "bin" and "get" to download the latest
     Atape driver in binary.  The current level of Atape at the
     time of this ptf is Atape.3.1.0.7.bin.