On Aug 23, 2007, at 5:36 AM, CAYE PIERRE wrote:

BUT when doing recurent task, as backup and so, TSM SEEMS to act as
Richard explain, asking the OS for a drive, so it's the OS which
make the choice, based on it own algorythm.

TSM performs I/O through operating systems services, but that is not
to say that the operating system makes choices.  In the case of Unix,
TSM performs an ioctl() system call with an appropriate "mount"
directive to cause the mount of a specific tape on a specific drive.
This is deterministic, with TSM choosing the drive to use.

   Richard Sims