Host Print Service Stops Responding After Invalid SCS Code (166625)

SYMPTOMS

A 3270 print session gets stuck in a spooling state when an invalid SCS control code is sent to the host print service. SNA Server Manager is slow to respond to requests when this problem occurs.

The Windows NT Application Event Log logs an Event 21, similar to the following:

   Event ID: 21
   Source: SNA Server
   Description: (1124) Negative Response Sent on Connection <connection
   name>
                        (SENSE = 1005)

When you stop the SNA Server host print service, the system returns to its normal responsiveness.

CAUSE

The SNA Server host print service does not correctly reset an error field after an invalid SCS control code is received from the host. This causes the print service to get into a loop that prevents print jobs from completing and may cause the system's responsiveness to slow, especially in SNA Server Manager.

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 3.0 and 3.0 Service Pack 1 (SP1). This problem was corrected in the latest SNA Server version 3.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

MORE INFORMATION

Print service internal traces that are captured when this problem occurs may include data similar to the following:

   INTRN SNAP-3270   S3PR1DAT            HPBYTE                  43
   INTRN SNAP-3270   S3PR1DAT            START OF SHF/SVF/SLD
   INTRN SNAP-3270   S3PR1DAT            CONTINUE
   INTRN SNAP-3270   S3PR1DAT            HPORDER                 2
   INTRN SNAP-3270   S3PR1DAT            PRTDSTRT                2872
   INTRN SNAP-3270   S3PR1DAT            HPBYTE                  131
   INTRN SNAP-3270   S3PR1DAT            SHF/SVF/SLD 2ND BYTE    83
   INTRN SNAP-3270   S3PR1DAT            EXIT
   INTRN SNAP-3270   S3PRDSCS           SCS DATASTREAM ERROR
   INTRN SNAP-3270   S3PRDSCS           EXIT
   INTRN SNAP-3270   S3PRRSCS           ENTRY

With the fix applied, the SNA Server host print service correctly handles invalid SCS control codes; the print service does not get into the loop that causes it to stop responding. The updated print service prints everything contained in the print job up to the invalid SCS control code. After the invalid SCS control code, the print service notifies the printer that the print job is finished.