Hello Richard:

The names of the directories are stored in the ADSM data base.  For
most directories there is no storage pool space associated with them.
There are some operating systems that support constructs such as ACLs
(access control lists).  Some of these are not files but extended
information associated with directories.  This would also apply to EA
data in HPFS386.  This additional information needs to be stored by
ADSM in a storage pool.  That is where the DIRMC option comes in.  This
allows you to control the management class that will get associated with
the directory information that needs to get stored in a storage pool.

This option was added because the data would get bound to the management
class that has a copygroup with the longest retention period.  In many
installations that was causing it to go directly to tape resulting in
excessive tape mounts.  The DIRMC option allows you to cause it to be
bound to a management class whose copygroup destination is a disk
storage pool so tape mounts are not needed until there is no space
available in the disk storage pool.

David Bohm, ADSM technical support.