TN3270E Print Job Hangs in Print Manager

• Microsoft SNA Server, versions 2.0, 2.1, 2.11
  on the following platforms: NT

SYMPTOMS

A TN3270E printer session hangs if the Host sends a BIND RU that specifies an Inbound Maximum RU size of 0 (indicating that no maximum RU size applies on the session to the Host). This causes the print job to remain in 'Spooling..." state in the Windows NT Print Manager until the Printer Session is disconnected.

This symptom occurs sporadically.

CAUSE

There are two causes to this problem:

1. The TN3270 Server incorrectly interprets 0 as the maximum RU size which prevents it from sending any data to the host. When the host establishes a session and specifies the maximum inbound RU size as "no maximum", the TN3270E Server treats this as an RU size of zero bytes. This has the effect that it ignores all the data it receives from a TN3270 or TN3270E client, apart from the 5-byte header in the case of TN3270E.



2. A TN3270E client may also misinterpret this byte and would then be unable to send any response to the TN3270 Server. The WRQ emulator is one such emulator.

RESOLUTION

There is a fix for cause number one and two:

1. The fix for cause number 1 ensures that the TN3270 sends inbound data. The data is sent in Request Units (RUs) up to the "Default Inbound RU Size" specified in the "Options" dialog of TN3270 Admin.



2. To work around the second cause, the client problem, the TN3270 Server has a registry entry that allows a 0 RU size in the BIND image transmitted to the client to be overwritten by the "Default Inbound RU Size" specified in the "Options" dialog of TN3270 Admin. You can find the registry entry under the subtree HKEY_LOCAL_MACHINE under the subkey:

   
   CurrentControlSet\Services\TN3270\Parameters 

   The registry value is as follows:

   Value Name: ReplaceRUSize
   Data Type: REG_EXPAND_SZ

   If this entry is set to "ON" then the value for the inbound RU size in the BIND Image sent to the TN3270E client is set to the default inbound RU size as configured for the TN3270E Server, if the host has specified no maximum.
   
   Set this registry entry only if you experience this problem.

• <TN3270Root>\TN3SERVR.EXE



• <TN3270Root>\TN3SERVR.DBG

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 2.00 2.10 2.11 3.50 3.51

Keywords : ntnetserv
Version : WINDOWS:2.0,2.1,2.11
Platform : WINDOWS
Issue type :