Hallo Jonny,
da gibt es dies aus dem Memo for Users:

3.46 Changed behavior for /QNTC directory

In V5R4, the following changes were made to the /QNTC file system:

* In releases prior to V5R4, the QZLC_SERVERLIST environment variable
was used to improve the performance for displaying the /QNTC
directory.

In V5R4 the default behavior is the same as setting QZLC_SERVERLIST
to 1 in previous releases. If you prefer the previous release default
behavior, you need to set the QZLC_SERVERLIST environment variable to
2. If you had previously set the QZLC_SERVERLIST environment variable
to 1, you do not need to take any action.

* Normal server connections are attempted using the IP name, rather
than the NetBios name. This change is consistent with changes that
were made in Windows 2000. In V5R4, NETSTAT shows the default QNTC
connection as a Remote Port of cifs or 445, rather than netbios or
139.
* You might experience changed behavior in your programs if you attempt
to set system attributes that are not supported by the QNTC file
system.

Attempts to set an unsupported attribute using a system API will
always result in an ENOTSUP(3440) error. Attempts to set an
unsupported attribute using the Change Attributes (CHGATR) command
will always result in the error message CPFA0AD (Function not
supported by file system).

In previous releases message CPFB414 (Attributes changed for 1
object), or a successful return code, would have been received, even
though the system attribute was not changed.

The following system attributes are among the system attributes that
QNTC does not support:

* *CCSID
* *ALWCKPWRT
* *USECOUNT
* *DISKSTGOPT
* *MAINSTGOPT
* *RSTDRNMUNL
* *CRTOBJAUD
* *SYSARCHIVE
* *CRTOBJSCAN
* *SCAN
* *ALWSAV