STOP Message when IBM Warp Client Connects to Windows NT 4.0

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

SYMPTOMS

When IBM OS/2 Warp network clients connect to Windows NT 4.0, the Server service may fail with the following Blue Screen Trap data:

   STOP: 0x0000000A (0x00002EE8, 0x00000002, 0x00000000, 0x8013A804)

CAUSE

The OS/2 network redirector still uses the server message block (SMB) Write Block Multiplexed (SMB MPX) to send larger amounts of data. Windows NT 4.0 does not correctly respond to this SMB and causes the server to fail.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. This problem was corrected in the latest Windows NT 4.0 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

MORE INFORMATION

SMB MPX comes into play when OS/2 is trying to send data from two processes over the same network connection at the same time (multiplexing).

Windows NT does not support this SMB on connection-based traffic. Instead, when the server receives a request with SMB MPX, it responds with a message telling the client to switch back to standard SMB Writes. The client will switch modes and keep on working with no problems.

Network performance studies have shown that SMB Raw Mode Reads and Writes provide better performance than MPX. This is why it is not supported under Windows NT.

There is one exception to this, however. Windows NT does support SMB MPX when using IPX Direct Hosting. Direct hosting is only available with Microsoft clients, so it does not come affect OS/2 interoperability. However, the Windows NT 4.0 failure occurs when the client is told to switch to standard SMB Write. The functions to send the response back to the client do not fully account for IPX and non-IPX clients.