Marc -

A 'dsmc Incremental <Fspec>' type backup where the Fspec identifies a
directory or file within a file system constitutes a partial
incremental backup.  It is still an Incremental, where the TSM server
(or JBB database) is referred to for the list of Active files within
the involved area.  An Incremental is supposed to observe ACLs.  A
partial incremental will not update the TSM filespace's last backup
time, whose intent is to signify when the file system was last fully
protected.

An Incrbydate backup is an intentionally more limited type of backup
whose reduced overhead is achieved by inspecting the file
modification timestamp relative to the last backup time.  By design,
that avoids a comparative files list and so cannot detect deleted
files or files which were imported to the file system (as via 'tar -
xvf') rather than normally written within the file system.

Employ a test directory to verify that the partial incremental is
achieving all that you desire.

  Richard Sims