I have an on-going problem with the tape mount exits on my VM server.
If the exit logs off too soon after the tape is attached to DSMSERV,
ADSM decides there is something wrong and issues this message:

ANR5241E Exit Machine DSMTAP1 not logged on, mount for A15689 cancelled.

It issues this message and cancels the mount even though the tape has
already been attached to it.

On the other hand, if the exit doesn't log off quickly enough after the
tape is attached to DSMSERV, DSMSERV tries to use the exit machine again,
finds that it is logged on, decides there is something wrong with it,
and stops using it.  Ultimately all of the exits are disabled.

And the timing here is very close.  I've been experimenting with
whether my exit should wait either 7 or 8 seconds after the tape
drive has been attached to DSMSERV before it logs off.  I seem to have
optimised the exit now in the sense that I get about equal numbers of the
two failures, but this is getting to be a pain.  I don't see the point of
ANR5241E.  Why should ADSM care whether the exit machine has logged off
by the time it notices that the tape has been attached?  (Or is it perhaps
checking the state of the exit before it notices the ATTACH?  I am quite
certain that the ATTACH has completed before my exit logs off.)  Is there
any way around this problem?  (I am running VM/ESA 1.0 with level 14 of
the server.)

Melinda Varian,
Princeton University