APPC DISPLAY Call May Return AP_COMM_SUBSYSTEM_ABENDED.

 Last reviewed: February 9, 1998
Article ID: Q180705
The information in this article applies to:
  • Microsoft SNA Server, versions 3.0, 3.0SP1, 3.0SP2, 4.0

SYMPTOMS

If a Win32 APPC application calls the SNA Server DISPLAY function to retrieve a list of all configured remote APPC LU's (in other words, sets the plu_def_info option), the following symptoms may occur:

  • the DISPLAY call may return with the following error: 

          primary_rc = 0xF003 (AP_COMM_SUBSYSTEM_ABENDED)
  • The following event may appear in the Windows NT application event log: 

          Event ID: 706
      Source:  SNA Server
      Description: 
      Connection to client <client>has been aborted due to too many (100) 
      pending writes.

This problem has been observed when configuring IBM Personal Communications for the AS/400 (version 4.1) while using the SNA Server Windows NT or Windows 95 client software. This problem occurs when the SNA Server is configured with a large number of local APPC LU/remote APPC LU/mode partnerships. In the customer's failure scenario, there were over 2300 local APPC LU's configured, each partnered with up to 4 remote APPC LU's.

CAUSE

The SNA Server was incorrectly reporting information on all the local APPC LU's defined, even though the application was only requesting remote APPC LUs (via the plu_def_info option). When attempting to send this large response to the client's DISPLAY request, the SNA Server exceeded 100 consecutive pending write requests to the client, causing the default "MaxPendingWrites" counter to be exceeded. For more information about Event 706 and MaxPendingWrites, see the following article in the Microsoft Knowledge Base: 

   ARTICLE-ID: Q142037
   TITLE: SNA Server Fails to Release Memory in SNA TCP/IP Interface DLL

STATUS

Microsoft has confirmed this to be a problem in SNA Server version 3.0, 3.0 Service Pack 1 (SP1), 3.0 SP2 and 4.0.

A supported fix is now available for SNA 3.0 and 4.0, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Product Support Services for more information. 

Keywords          : kbbug3.00 kbbug3.00.sp1 prodsna snaappc snaprog snaserverservice kbbug3.00.sp2 kbbug4.00
Version           : WINDOWS:3.0,3.0SP1,3.0SP2,4.0
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbfix

================================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Last reviewed: February 9, 1998
© 1998 Microsoft Corporation. All rights reserved. Terms of Use.