Print Jobs May Not Finish Printing if Host Sends SHUTD

ID: Q216123

The information in this article applies to:

Microsoft SNA Server, versions 3.0, 3.0SP1, 3.0SP2, 3.0SP3, 4.0, 4.0SP1, 4.0SP2

SYMPTOMS

Host print jobs printed through SNA Server's Host Print service may not print in their entirety if the host issues a SHUTD (Shutdown) command after the print data has been sent to the print server. For example, a print job that contains three pages of data may result in two pages of actual output when this problem occurs.

CAUSE

SNA Server's Host Print service immediately issues a SHUTC (Shutdown Complete) command when it receives a SHUTD command from the host instead of waiting until the print job is complete. After the host receives the SHUTC command from an application (that is, the print server), any further Request Units (RUs) that are queued for that particular session are not sent. This problem occurs when there are additional RUs waiting to be sent to the print server when the SHUTC is received by the host. The missing print output is contained in these RUs.

RESOLUTION

SNA Server 4.0

To resolve this problem, obtain the latest service pack for SNA Server version 4.0. For additional information, please see the following article in the Microsoft Knowledge Base:

Q215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack

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:

Q184307 How to Obtain the Latest SNA Server Version 3.0 Service Pack

STATUS

Microsoft has confirmed this to be a problem in Microsoft SNA Server versions 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 4.0, 4.0 SP1, 4.0 SP2. This problem was first corrected in SNA Server version 3.0 Service Pack 4 and SNA Server version 4.0 Service Pack 3.

MORE INFORMATION

SNA messages can be sent with two different priorities: normal and expedited. Expedited messages take precedence over other messages waiting to be sent on the same session. SHUTD and SHUTC commands are sent as expedited messages. Because SHUTD commands are sent as expedited messages, it is possible for these to be sent prior to normal messages already queued for the same session. The problem described in this article occurs when a SHUTD message is sent to SNA Server's Host Print service before some of the preceding normal messages are sent. The following is an example of how the host print data was intended to be sent and processed:


Host                           SNA Server                 Print Server
----                           ----------                 ------------
Data (Begin Bracket)  ->
                               Data (Begin Bracket)  ->
                                                     <-   Acknowledgement
                      <-       +RSP
Data                  ->
                               Data                  ->
                                                     <-   Acknowledgement
                      <-       +RSP
Data                  ->
                               Data                  ->
                                                     <-   Acknowledgement
                      <-       +RSP
Data (End Bracket)    ->
                               Data (End Bracket)    ->
                                                     <-   Acknowledgement
                      <-       +RSP
SHUTD                 ->
                               SHUTD                 ->
                      <-       SHUTD +RSP
                                                     <-   SHUTC
                      <-       SHUTC
SHUTC +RSP            ->
UNBIND                ->

In this case, the SHUTC is sent after the last print data as noted by the End Bracket (EB) indicator. Therefore, the entire print job completes.

The following is a sample sequence that results in only part of the print data actually being printed:


Host                           SNA Server                 Print Server
----                           ----------                 ------------
Data (Begin Bracket)  ->
                               Data (Begin Bracket)  ->
                                                     <-   Acknowledgement
                      <-       +RSP
Data                  ->
                               Data                  ->
                                                     <-   Acknowledgement
                      <-       +RSP
SHUTD                 ->
                               SHUTD                 ->
                      <-       SHUTD +RSP
                                                     <-   SHUTC
                      <-       SHUTC
SHUTC +RSP            ->
UNBIND                ->

In this case, the last two data messages shown in the first example above are not shown as they never reach the SNA Server. The data messages are not shown because the SHUTD/SHUTC sequence occurred before these normal data messages could be sent.

If the device (that is, IBM 3745 or Cisco Routers) that is responsible for sending the actual host messages to the SNA Server has some normal and expedited messages for the same host session, it is possible that the expedited messages will be sent prior to normal flow messages.

After applying the update, SNA Server's Host Print service can be configured so that it will not issue a SHUTC command in response to a SHUTD command until an RU with an End Bracket indicator is received. This prevents the print server from issuing the SHUTC command immediately on the receipt of the SHUTD command, which caused the problem described here.

The following Registry entry has to be configured to allow the print server to delay the SHUTC command processing.

Start Registry Editor (Regedt32.exe).

Locate the following key in the registry:
```
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SnaPrint\Parameters
   
```
NOTE: The above registry key is one path; it has been wrapped for readability.

On the Edit menu, click Add Value, and then add the following registry value:


      Value Name: SHUTCafterEB
      Data Type:  REG_SZ
      Value:      YES

Quit Registry Editor.

Additional query words:

Keywords : sna3sp4fix sna4sp3fix
Version : WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,4.0,4.0SP1,4.0SP2
Platform : WINDOWS
Issue type : kbbug