DOCUMENT:Q193813 24-OCT-2001 [sna] TITLE :Multiple NVRunCmd Commands May Cause Unpredictable Results PRODUCT :Microsoft SNA Server PROD/VER::2.11,2.11 SP1,2.11 SP2,3.0,3.0 SP1,3.0 SP2,3.0 SP3,4.0,4.0 SP1 OPER/SYS: KEYWORDS:kbbuglist ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft SNA Server, versions 2.11, 2.11 SP1, 2.11 SP2, 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 4.0, 4.0 SP1 ------------------------------------------------------------------------------- SYMPTOMS ======== An SNA Server may experience unpredictable behavior if it receives multiple NVRunCmd commands from the host over one of its configured host connections. This will only occur if the SNA Server receives NVRunCmd commands while it is currently processing a previous NVRunCmd. The following is a sequence that caused the PU (Physical Unit) defined in VTAM for a SNA Server host connection to hang: Host SNA Server ---- ---------- (1) NMVT (DIR D:\SNA\SYSTEM\*.*) -> (2) NMVT (DIR C:\*.*) -> <- (2) NMVT -RSP (Sense 084B0003) <- (1) Data (1st portion of data) (3) NMVT (DIR C:\*.*) -> <- (1) (Final data for NMVT #1) In this sequence, the host sends three NVRunCmds over the connection defined in SNA Server. The first NVRunCmd command (designated as number 1) is accepted, and eventually completes, returning the contents of the D:\Sna\System directory. The second NVRunCmd command (designated as number 2), is rejected by SNA Server. This request is rejected with an IBM Sense Code of 084B0003, which indicates that the requested resources are not available. SNA Server does not respond to the third NVRunCmd command (designated as number 3) at all. The lack of response is what causes the PU defined for this host connection to hang. It is possible that other symptoms may also occur since SNA Server is not correctly handling multiple concurrent NVRunCmd commands. CAUSE ===== The NVRunCmd service is designed to process only one command at a time. If subsequent commands are received while a previous command is being processed, the subsequent NVRunCmd commands will be rejected by SNA Server. The problem is that the SNA Server service doesn't properly handle the case when multiple NVRunCmd commands are received at the same time. When this occurs, the SNA Server may correctly reject one or more of the commands it receives while processing the initial request. However, it may also attempt to process one of the NVRunCmd commands while the initial request is still processing, and this can lead to unpredictable results such as the PU hanging. RESOLUTION ========== SNA Server 3.0 -------------- To resolve this problem, obtain the latest service pack for SNA Server version 3.0. For additional information, please see the following article in the Microsoft Knowledge Base: Q219049 How to Obtain SNA Server Version 3.0 Service Pack 4 SNA Server 4.0 -------------- Microsoft has confirmed this to be a problem in SNA Server version 4.0 and 4.0 SP1. This problem was corrected in the latest SNA Server version 4.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces): S E R V P A C K STATUS ====== Microsoft has confirmed this to be a problem in SNA Server versions 2.11, 2.11 SP1, 2.11 SP2, 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 4.0, and 4.0 SP1. This problem was first corrected in SNA Server 3.0 Service Pack 4. MORE INFORMATION ================ After applying the hotfix for this problem, SNA Server will reject all subsequent NVRunCmd commands if a NVRunCmd command is being processed. For more information on the NVRunCmd service, please refer to one of the following: - SNA Server Administration Guide - SNA Server Online Help Additional query words: ====================================================================== Keywords : kbbuglist Technology : kbAudDeveloper kbSNAServSearch kbSNAServ300 kbSNAServ211 kbSNAServ400 kbSNAServ211SP1 kbSNAServ211SP2 kbSNAServ300SP3 kbSNAServ300SP1 kbSNAServ400SP1 kbSNAServ300SP2 Version : :2.11,2.11 SP1,2.11 SP2,3.0,3.0 SP1,3.0 SP2,3.0 SP3,4.0,4.0 SP1 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. Copyright Microsoft Corporation 2001.