Knowledge Base

Large Ntbootdd.sys File May Cause Problems

Article ID: 198524

Article Last Modified on 10/31/2006

Microsoft Windows NT Server 4.0 Standard Edition
Microsoft Windows NT Workstation 4.0 Developer Edition

This article was previously published under Q198524

SYMPTOMS

When you use the SCSI() syntax in the Boot.ini file to boot a computer using a SCSI adapter that does not have INT 13h BIOS support, the computer may stop responding (hang). In Windows NT 4.0, you may receive a "Trap E" message.

Some SCSI adapters have partial INT 13h BIOS support, in that the BIOS supports only two disk drives. The problem can occur when you try to boot from a drive not supported by the BIOS.

CAUSE

The SCSI() syntax requires the Ntbootdd.sys file. If the size of the Ntbootdd.sys file exceeds approximately 64 kilobytes (KB), the problem may occur.

RESOLUTION

To work around this issue, try any of the following methods:

Verify that the size of the Ntbootdd.sys file is less than 64 KB.
Use a SCSI adapter with full INT 13h BIOS support.
Boot using a disk supported by the BIOS.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

The Ntbootdd.sys file is not required if the SCSI adapter has INT 13h BIOS support. The Ntbootdd.sys file is a renamed copy of the SCSI device driver located in the root folder. This file is also used with Windows NT Startup floppy disks.

Keywords: kbenv kbpending kbprb KB198524