HEIDENHAIN iTNC 530 (340 49x-01) ISO programming - Manual (Page 564)

564 14 iTNC 530 with Windows 2000 (Option)
14.4 Netw
or
k Set
tings
Controlling access
Administrators have access to the TNC drives D, E and F. Please note
that some of the data in these partitions is binary encoded, and write-
accesses might lead to undefined behavior of the iTNC.
The partitions D, E and F have access rights for the user groups
SYSTEM and Administrators. The group SYSTEM ensures that the
Windows service that starts the control has access. The group
Administrators ensures that the real-time processor of the iTNC
receives a network connection via the iTNC Internal Connection.
You may not restrict access by these groups, nor may you
add groups and prohibit certain accesses by these groups
(in Windows, access restrictions have priority over access
rights).