IBM MPA/A (MCA) SDLC Adapter Not Detected on Dual-Bus Servers

 Last reviewed: March 19, 1998
Article ID: Q161776

The information in this article applies to:

  • Microsoft SNA Server, versions 2.11, 2.11 Service Pack 1 (SP1), 2.11 SP2, 3.0, and 3.0 SP1

SYMPTOMS

When you install the IBM SDLC link service on an IBM PC Server 320 or 350, SNA Server Setup fails to detect the IBM SDLC Multifunction adapter /A (Microchannel) adapter. If you ignore this error, Setup adds the SDLC link service, but the link service remains pending and will not activate.

CAUSE

When detecting the IBM MPA/A adapter, SNA Server Setup only looks for the first hardware bus record in the Windows NT registry. However, these servers have both a PCI and an MCA bus. The first bus is identified as PCI, so this fails to match the expected MCA entry.

RESOLUTION

To resolve this problem, either apply the fix referenced below (see "STATUS") or use the following workaround:

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

  1. Start Registry Editor (Regedt32.exe or Regedit.exe, as appropriate for your version of Windows NT).

  2. Go to the following key in the registry:

    HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter\0

  3. Change the Identifier value from PCI to MCA, as follows: 

          Identifier: REG_SZ: MCA

  4. Quit Registry Editor.

  5. Re-run the SNA Server Setup program. Do NOT restart the computer first; Windows NT dynamically sets this registry value when starting and will change it back to PCI.

Setting the value to MCA allows the Setup program to detect the adapter and configure the correct CardCfg entries for the adapter. The SDLC link service will continue to function even after the computer is restarted.

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 2.11, 2.11 Service Pack 1 (SP1), and 2.11 SP2. A supported fix is now available. Contact Microsoft Technical Support for more information.

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

A fix for this problem is available from Microsoft for both 2.11 and 3.0. With the fix applied, the Sync card detection module (syncdtct.dll) loops through all NetworkCard registry keys.

IBM PC Server 320 and 350 are manufactured by IBM, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability. 

Keywords          : snasdlc kbfix3.00.sp2 kbnetwork
Version           : winnt:2.11,3.0
Platform          : winnt
Issue type        : kbbug
Solution Type     : kbfix

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Last reviewed: March 19, 1998
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