Before manipulating files in the UNIX file system, SMP/E temporarily switches the user ID that is executing the SMP/E task to superuser authority (UID=0) and restores the user ID to the previous level of authority when the SMP/E updates are complete. This includes any actions performed on SMP/E's behalf by the HFSCOPY and link edit utilities.

This means SMP/E users are not required to have UID=0 (superuser) authority all the time, which reduces the chance of such users accidentally erasing or damaging files in a UNIX file system while performing non-SMP/E work. However, the user ID that executes an SMP/E task must be defined to the BPX.SUPERUSER facility class profile for this process to work properly.