Installing Windows NT on a Large IDE Hard Disk

During the installation of Microsoft Windows NT to an 8 gigabyte (GB) or larger IDE hard drive, the computer may stop responding (hang) during the format portion of setup. If the drive was previously formatted as file allocation table (FAT) and designated to be converted to NTFS file system (NTFS), the computer may hang during the conversion process. Other symptoms include the drive taking an extremely long time to format or Windows NT not recognizing the entire size of the drive.

The Microsoft supplied generic IDE driver (Atapi.sys) may not be fully compatible with drives larger that 8GB. This issue only affects IDE-based drives 8 GB and larger.

Windows NT 4.0 Service Pack 4 (SP4) has a new Atapi.sys file that allows the drive to be formatted during setup of Windows NT. SP4's Atapi.sys can also access space beyond 8GB on these IDE drives.

The system partition (boot partition) is still limited to 7.8GB whether an updated version of the Atapi.sys file is installed or not.

For more information, please see the following article in the Microsoft Knowledge Base:
NOTE: The system board basic input/output system (BIOS) must support and recognize drives larger than 8GB before Windows NT can access the entire drive. You can verify this ability by entering into the BIOS or contacting your system board manufacturer.

Microsoft has confirmed this to be an issue in the Microsoft products listed at the beginning of this article.

For related issues that this article addresses, please see the following articles in the Microsoft Knowledge Base: