How to Manually Add Support for a Second Processor

This article describes how to change Windows NT from single processor support to multiprocessor support or from multiprocessor support to single processor support.

Before you start, make sure that you have a complete, working backup of the system files and the registry, and that you have a current Emergency Repair Disk (ERD). To create an updated ERD, run Rdisk.exe from a command prompt, and then select Update Repair Info.

To add support in Windows NT for an additional processor, follow these steps:

NOTE: Some Compaq computers require a different HAL -- Halsp.dll. Refer to the latest Compaq Software Support Disk SSD for details.

1. Install Windows NT to a separate folder on your hard disk, and then restart your computer to the new installation of Windows NT.
2. In the %SystemRoot%\system32 folder of your original Windows NT installation, rename the following files to alternate names:
   Ntoskrnl.exe
   Hal.dll
   Kernel32.dll
   Ntdll.dll
   Winsrv.dll
   Win32k.sys (additional file in Windows NT 4.0 only)
3. Determine which multiprocessor HAL your computer requires using the following list:

         Halast.dll    = "AST Manhattan SMP"
         Halsp.dll     = "Compaq SystemPro Multiprocessor or 100% Compatible"
         Halcbus.dll   = "Corollary C-bus Architecture"
         Halmca.dll    = "IBM PS/2 or other Micro Channel-based PC"
         halmpsm.dll   = "Micro Channel Multi Processor PC"
         Halapic.dll   = "MPS Uniprocessor PC"
         Halmps.dll    = "MPS Multiprocessor PC"
         Halncr.dll    = "NCR System 3000 Model 3360/3450/3550"
         Haloli.dll    = "Olivetti LSX5030/40"
         Hal.dll       = "Standard PC"  (single processor HAL)
         Hal486c.dll   = "Standard PC with C-Step i486"
         Halwyse7.dll  = "Wyse Series 7000i Model 740MP/760MP"
   					

4. NOTE: The Ntkrnlmp.exe and appropriate HAL file need to be the same version as that of the NT installation. Failure to get files from the appropriate service pack will result in system instability and error message on blue screens. This also applies for files that require manual expansion with the Expand.exe tool that need to be obtained from the service pack cd or directory location.
   
   Copy the Ntkrnlmp.exe file and the appropriate HAL file from the Windows NT CD-ROM to the %SystemRoot%\system32 folder of your original Windows NT installation. If a service pack has been installed to the system, copy the files from the current service pack version cd or install location to the %SystemRoot%\system32 folder of your original Windows NT installation. Once the files are in place, rename them to Ntoskrnl.exe and Hal.dll, respectively.
5. Copy the Ntdll.dll file from the original Windows NT CD-ROM %SystemRoot%\system32 folder of your original Windows NT installation. If a service pack has been installed to the system, copy the files from the current service pack version cd or install location to the %SystemRoot%\system32 folder of your original Windows NT installation.
6. From a command prompt, expand the Kernel32.dll and Winsrv.dll files from the Windows NT CD-ROM or installed service pack to the %SystemRoot%\system32 folder of your original Windows NT installation. For example, type the following commands:
   expand kernel32.dl_ %systemroot%\system32\kernel32.dll
   expand winsrv.dl_ %systemroot%\system32\winsrv.dll
   NOTE: To properly expand files from the Windows NT CD-ROM, you must use the Expand.exe utility included with Windows NT. The Windows NT Expand.exe utility can only be run from a command prompt in a 32-bit environment such as Microsoft Windows 95 or Windows NT.
   
   NOTE: In Windows NT 4.0, the Win32k.sys file is also required. Expand it from the original Windows NT CD-ROM or the installed service pack.
   
   
7. Restart your computer.
8. When the Windows NT kernel loads, ensure that it displays "Multiprocessor kernel" during startup.

Support for the second processor is now installed and is ready for use. To return to single processor support, restore the old files to the original names in the %System Root%\System32 folder, and then restart the computer.

NOTE: The files located on the Window NT CD-ROM and in the service packs are multiprocessor-aware. To return to a single processor, you must install Windows NT on a single-processor computer, install any applicable service packs, and then copy the associated files from that computer to the computer you want to return to a single processor. You should also update the Setup.log file in the $SystemRoot%\Repair folder to reflect the correct state of your computer in order for future service packs and the repair process to function properly. To update the Setup.log file you must manually enter the correct file and checksum value. For a listing of the correct values, see the following article in the Microsoft Knowledge Base: For additional information, see the following articles in the Microsoft Knowledge Base: NOTE: When you change to or from single or multiple processors, if you are using Proxy 2.0 server on the same computer, you also need to replace the Ipfltdrv.sys driver as well (%SystemRoot%\system32\drivers). The single- processor version is 36 KB in size and is located on the Proxy 2.0 CD-ROM in the Msproxy\I386\Routing\Up folder. The multiple-processor version is 34 KB in size and is located on the Proxy 2.0 CD-ROM in the Msproxy\I386\Routing folder.