TN3270E emulator may stop responding when you log off a mainframe application

View products that this article applies to.

Symptoms

A TN3270E emulator may stop responding when you log off a mainframe application. When the problem occurs, the TN3270E emulator may display a message that indicates that the previous command completed or that the logoff is in progress. The exact symptoms vary depending upon the mainframe applications that are used. The TN3270E emulator cannot send or receive any data after this problem occurs.

When the user logs off the mainframe application, the expected behavior is that the TN3270E emulator will display a previous mainframe application menu.

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Cause

The TN3270 service does not reset a stored Request Unit (RU) when the TN3270 service receives a CLEAR command from a mainframe application.

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Resolution

Service pack information

To resolve this problem, obtain the latest service pack for Microsoft Host Integration Server 2000. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

328152� How to obtain the latest service pack for Host Integration Server 2000

Hotfix information

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Time   Version      Size     File name
   ------------------------------------------------------
   23-Apr-2004  18:12  5.0.0.978    258,320  Tn3servr.exe

Note Because of file dependencies, the most recent hotfix that contains these files may also contain additional files.

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Workaround

To work around this problem, make sure that the emulator is configured to connect to the TN3270 server in TN3270 only mode.

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Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

This problem was corrected in Microsoft Host Integration Server 2000 Service Pack 2.

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More information

The following is an example of the data flow that causes the problem that this article describes:

A user issues a command to log off a mainframe application such as Information Management System (IMS).
The mainframe application sends an RU that indicates that the previous command has completed or that the logoff is in progress.
The mainframe application sends a CLEAR command.
The mainframe application sends a Start Data Traffic (SDT) command.
The mainframe application sends a data RU that contains a 3270 Write command and a Write Control Character (WCC).
The mainframe application sends a second CLEAR command.
The mainframe application sends a second SDT command.
The mainframe application sends a second data RU that contains a 3270 Write command and a Write Control Character (WCC).

The TN3270 server stores the first data RU that is made up of the 3270 Write and the WCC, but the TN3270 server does not reset the stored RU when the CLEAR command is received. The result is that the TN3270 server sends the final data RU to the TN3270E in an incorrect format, causing the TN3270E emulator to stop responding to user input.

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