Some SNA Print Sessions May Remain Pending when Autostarted (247816)

SYMPTOMS

Print sessions may freeze in a pending state on a print server that is configured to auto-activate a large number of print sessions. Right-clicking a print session in SNA Server Manager and selecting Stop has no effect. "Active" printers, however, can be stopped and started successfully. Windows NT can successfully generate a test page to the same network printer that the "pending" print session shows as the destination printer.

CAUSE

When an SNA print session is started, it is assigned to a thread. There are 32 threads available for SNA print sessions, so multiple print sessions can be assigned to each thread. For additional information on the print server's threading model, click the article number below to view the article in the Microsoft Knowledge Base:

239861 SNA Server Host Print Service Supports 1,024 3270 Print Sessions

After the print sessions are assigned to specific threads, a DeviceCapabilities request is sent to the print driver for each print session. SNA print sessions cannot activate until they receive a response to the GetDeviceCapabilities request. When a large number of print sessions are started simultaneously, certain print drivers may not respond to the request. When that happens, the thread hangs. The result is that all SNA print sessions assigned to that particular thread remain in a "pending" state. Hewlett Packard PCL6 and PCL5e drivers have problems handling multithreaded simultaneous requests. Printers known to have this problem:

HP4000 series
HP8000 series

RESOLUTION

To resolve this problem, obtain the latest service pack for SNA Server 4.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack

Hewlett Packard has posted three new drivers that solve this problem to its Web site. They are for the LJ4050, LJ8000, and LJ8100 models and are PCL6 NT drivers. The version number for these are all 4.2.1.12. To obtain these files, go to the Hewlett Packard Web site http://www.hp.com/go/lj_software and select the printer model. (As of this writing, the Hewlett Packard Website does not show the correct version numbers, but this will reportedly be corrected.)

WORKAROUND

To work around this problem:

Replace the Hewlett Packard PCL6 and PCL5e drivers with the older Hewlett Packard PCL4 drivers. -or-
Configure the SNA print sessions to use a PDT (printer definition table). PDTs provide functions similar to printer drivers. They translate GDI (graphic device interface) calls to control printer-specific codes. This will bypass the DeviceCapabilities call completely. The threads will not hang. A better description of PDTs and their capabilities is listed in the SNA Print Service white paper. The SNA Print Service white paper can be downloaded from http://www.microsoft.com/sna/guide. The white paper was recently revised and now includes a section for Capacity and Recommendations. Microsoft recommends a maximum of 240 GDI print sessions, but this limit is raised to 500 for non-GDI print sessions. Print sessions using a PDT are considered non-GDI print sessions. -or-
Upgrade to SNA Server 4.0 Service Pack 4.

MORE INFORMATION

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.