Installing TN3270 breaks Performance Counters on Windows NT 4.0

• Microsoft SNA Server for Windows NT, versions 3.0 and 3.0 SP1

SYMPTOMS

When installing SNA Server on a Windows NT Server version 4.0 other than English or Japanese, the currently installed counters may be lost.

CAUSE

The problem only happens when installing a TN3270 Server. The TN3270 option is selected by default on the SNA Server 3.0 setup tool. The TN3PERF.INI file included in SNA 3.0 and SNA 3.0 SP1 has an entry for all languages, but has only counters definitions for English and Japanese. When an .INI file, which contains an extra language entry not associated with any specific objects and counters, is passed as a parameter to Windows NT LODCTR.EXE, the values of 'Last Counter' and 'Last Help' are set to zero. This causes the Performance Monitoring tool to only display the TN3270 counters.

This was an NT 3.50 bug in LODCTR.EXE fixed in 3.51, but back in Windows NT 4.0. For more information about this bug, see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q128404
   TITLE: FIX: Corruption of the Perflib Registry Values

RESOLUTION

It is enough to uncheck the TN3270 option at setup time. In the case where the TN3270 Server feature is needed, the TN3PERF.INI has been modified so it now includes full language support.

As this file is used by the setup program, the installation files must be moved from the CD-ROM to a local drive. This will allow the user to replace the current TN3PERF.INI file with the one provided as part of this fix before running the setup program from that local drive.

In the case the user already installed the TN3270 Server feature and that the Counters have been lost, refer to the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q128404
   TITLE: FIX: Corruption of the Perflib Registry Values

STATUS

Microsoft has confirmed this to be a problem in SNA Server version 3.0 Service Pack 1. A fix to this problem is in development, but has not been regression-tested and may be destabilizing in production environments. Microsoft does not recommend implementing this fix at this time. Contact Microsoft Product Support Services for more information on the availability of this fix.