>We recently upgraded from ADSM 3.1.2.20 to TSM 4.1.2.0 on AIX 4.3.3 with
>3494 ATL.   Shortly after the upgrade, we started to experience a situation
>where the ATL is "refusing" nearly all mount requests, even though
>sufficient drives are available.  The message is "ANR8447E no drives are
>currently available in library".  Scratch mounts as well as volser mounts
>are failing.  The IBM CE says the service log on the 3494 shows no
>indication of a mount being requested.  Occasionally, a mount is satisfied
>so we're actually able to perform some amount of productive work.  The
>devclass is defined as mountl=drives.  The 3494 is not shared.

Bob - There might be problems with 4.1.2.0; but first do the usual 3494
      type of checking...
In the server, do 'show libr' and see if it thinks all the drives are
available.
In the 3494, do an availability check at its operator station and see
if it shows all drives available.  (They might be marked unavailable
from either the Library Manager there, or from drive front panels.)
In AIX, do 'lsdev -C -c tape -H -t 3590' and see if all drives have
status of Available.
If no dice from the above, try setting an explicit Mountlimit value,
rather than depend upon "Drives" and see if any difference.

  Richard Sims, BU