Print Service May Cause Incomplete Printout with LU Type 3

• Microsoft SNA Server, versions 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 3.0 SP4, 4.0, 4.0 SP1, 4.0 SP2

SYMPTOMS

A print output may be incomplete with LU Type 3. You may also see that whole pages are missing.

CAUSE

The data buffer provided by the SNA Print Service is too small when a buffer size is determined dynamically. When this occurs, the buffer can be overwritten and therefore, not all incoming data is flushed to the printer.

RESOLUTION

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

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, 3.0 SP4, 4.0, 4.0 SP1, 4.0 SP2. This problem was first corrected in SNA Server version 4.0 Service Pack 3.

MORE INFORMATION

The problem described can only occur with LU 3 sessions using dynamic buffer sizes.

Buffer sizes (also known as screen sizes) are specified in the BIND Request Unit, Byte 20-24.
In the reported case, the screen size was determined dynamically (that is, by the CarriageReturn and EndOfMedium characters). In this situation, the provided data buffer was too small and wrapped, so that the initial character was overwritten by an EOM (End of Media) character. When the data were flushed to the printer, the entire screen was lost because the EOM character is the 'end delimiter' in a data buffer, so nothing else was sent to the printer.

When Print Service internal traces are enabled, you might see the following trace output:

(session: LU3PRT, job #1) ******* PARSE DATA **********
SNAP-3270 S3PRLCPP <B>More to print</B> 
SNAP-3270 S3PRLCPP LCCOL = 132
next character: 19
SNAP-3270 S3PRLCPP CTLCODE = EM @BUFPOS 0
(session: LU3PRT, job #1) byte: 19 -> end message
SNAP-3270 S3PRLCPP EOS = 1919
(session: LU3PRT, job #1) ******* FLUSH DATA ********** 

Additional query words:

Keywords : sna4sp3fix sna3 sna3sp1 sna3sp2 sna3sp3 sna3sp4 sna4 sna4sp1 sna4sp2
Version : WINDOWS:3.0,3.0 SP1,3.0 SP2,3.0 SP3,3.0 SP4,4.0,4.0 SP1,4.0 SP2
Platform : WINDOWS
Issue type : kbbug