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Q139785: RUI Problem Handling RUI_SEND After Sense Data Received

Article: Q139785
Product(s): Microsoft SNA Server
Version(s): WINDOWS:2.1,2.11
Operating System(s): 
Keyword(s): 
Last Modified: 13-JUN-2001

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The information in this article applies to:

- Microsoft SNA Server, versions 2.1, 2.11 
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SYMPTOMS
========

If the host application sends sense data to an RUI application while the RUI
application is sending data, the SNA Server RUI library queues the application
data in error and never sends it, causing the RUI application and the host
application to become unsynchronized.

CAUSE
=====

The RUI application gets the sense data indicator (SDI) message and correctly
sends negative response. Because the RUI library is in the middle of a chain (it
has only received Begin Chain - BCI, not End Chain - ECI) it sets a flag telling
it to discard all data messages until it receives one with ECI set.
Unfortunately the server performs the same check. Therefore the RUI library does
not see the ECI flag until it receives the end of the NEXT chain (the retried
one).

RESOLUTION
==========

The RUI application can't work around this problem. The solution is for the RUI
library to detect that a new chain is starting without the purging one ending,
and simply to stop purging at that point.

An update to the SNA Server RUI DLL corrects this problem. Note that with this
update applied, the RUI application will still miss the Middle of Chain (MC) and
EC sequence numbers on the rejected chain. Microsoft has updated the following
files to correct this problem:

  Client Platforms     Updated Files
  -----------------------------------------------------------
  Win32                <snaroot>\system\WINRUI32.DLL
  Windows 3.x          <winroot>\system\WINRUI.DLL
  OS/2                 <snaroot>\ACSRUI.DLL


STATUS
======

Microsoft has confirmed this to be a problem in SNA Server for Windows NT. This
problem was corrected in the latest SNA Server for Windows NT, 2.11 U.S. Service
Pack. For information on obtaining the Service Pack, query on the following word
in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K

Additional query words: prodsna 2.10 2.11

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ211 kbSNAServ210
Version           : WINDOWS:2.1,2.11

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