RUI_READ Stops When Processing Buffers Larger Than 3 KB (162626)
The information in this article applies to:
- Microsoft SNA Server 2.0
- Microsoft SNA Server 2.1
- Microsoft SNA Server 2.11
- Microsoft SNA Server 2.11 SP1
- Microsoft SNA Server 3.0
This article was previously published under Q162626 SYMPTOMS
An RUI_READ (immediate) will stop when an RU size is greater than 3 KB. No
errors are generated; however, the application does not respond.
CAUSE
When an application has issued an RUI_BID verb, the WINRUI32 library will
post the verb as soon as 12 or more bytes of RU data are available to
return to the application. Normally, due to the nature of the message-
passing mechanism between SNA Server and the RUI library, this means
that the complete RU has been received by the RUI library, and when the
application issues a subsequent RUI_READ(immediate), the RUI_READ will
complete successfully.
However, when the RU size on the session exceeds a certain size (just over
3 KB), SNA Server will split the messages it sends to the RUI library
into smaller blocks. The RUI library, however, continues to complete the
RUI_BID when it receives the first block of a new RU. If the application
issues an RUI_READ(immediate) before the remainder of the RU arrives, the
RUI_READ will complete with a return code of UNSUCCESSFUL. This will
confuse any application that (rightly) expects all the data to be available
when the RUI_BID is posted.
RESOLUTION
A fix to the RUI library has been created to prevent it from posting an
RUI_BID until all the blocks of a large RU have been received.
Updated files:
Windows NT: <Snaroot>\System\Winrui32.dll
Windows 95: <Winroot>\System\Winrui32.dll
Windows 3.x: <Winroot>\System\Winrui.dll
OS/2: <Snaroot>\System\Rui.dll
MS-DOS: <Snaroot>\Dosacs.lib (application must be relinked)
STATUS
Microsoft has confirmed this to be a problem in SNA Server versions 2.0,
2.1, 2.11, 2.11 Service Pack 1, and 3.0. This problem was corrected in the latest SNA Server for Windows NT, 2.11 and 3.0 U.S. Service Packs. For information on obtaining these service packs, query on the following word in the Microsoft Knowledge Base (without the spaces):
| Modification Type: | Major | Last Reviewed: | 11/26/2003 |
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| Keywords: | kbnetwork KB162626 |
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