Adding More Than Two IDE or ESDI Drives in Windows NT

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1
• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

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.

If a computer has more than two IDE or ESDI hard disk drives and needs an MS-DOS-based device driver to use the extra drives, Windows NT may not be able to use the extra drives by default.

To configure more than two IDE or ESDI hard disk drives with Windows NT, the Windows NT Registry must be modified to add the information about the additional drives. You need technical information about your drives, which should be included in the documentation included with them.

NOTE: To make the changes in the Registry, you must be logged on as an Administrator.

MORE INFORMATION

This procedure should only be necessary if you are adding a third or higher IDE or ESDI hard disk drive or if your secondary IDE or ESDI drive is at a non-standard address. If the drive is at a non-standard address, use the following procedure to add the correct address in the Windows NT registry. The registry key name in this case would be either 1 or 2.

NOTE: The information in this article applies only to Intel x86 architecture computers.

To add support for three or more IDE or ESDI hard disk drives in Windows NT, follow these steps:

1. Open the Registry Editor (REGEDT32.EXE).

2. Locate the following registry key:

         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Atdisk
   

3. On the Edit menu, click Add Key to create the following key:

         Key Name: PARAMETERS
         Class: <blank>
   

4. Open the PARAMETERS key that you created in Step 3.

5. On the Edit menu, click Add Key to create the following key:

         Key Name: <number>
         Class: <blank>
   

   where <number> is the number of the additional drive, such as 2 for the third drive. For each additional drive, increment the Key Name by 1. In general, you must specify the starting parameter as 2 or higher. This prevents a conflict with the primary or secondary controller that most BIOS's support.

6. Open the key that you created in step 5.

7. On the Edit menu, click Add value to add the following values:

         BaseAddress
         -----------
         This is the physical address of the Data register for the
         controller.
   

         DriveControl
         ------------
         This is the physical address of the drive control register of
         the controller. Often this is 0x206 off of the BaseAddress
         register.
   

         Interrupt
         ---------
         This is the interrupt that the controller will use.
   

   Set the Data Type of all three entries to REG_DWORD.

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Atdisk
   \Parameters\2

       BaseAddress = REG_DWORD 0x320
       DriveControl = REG_DWORD 0x32e
       Interrupt = REG_DWORD 0xa