Windows NT 4.0 May Not Recognize SCSI Devices Using Nonzero LUNs

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

SYMPTOMS

Windows NT 4.0 may not recognize a SCSI device that uses a logical unit number (LUN) other than zero and that comes online after the system is started.

NOTE: Hardware RAID devices commonly use nonzero LUNs.

CAUSE

This problem is caused because the Scsiport.sys driver does not scan for non-zero LUNs if LUN 0 has already been detected.

For example, you have a system with a single SCSI disk drive at ID=0, LUN=0, and start the computer. Next, you turn on an external drive that is configured for ID=0, LUN=1. The Windows NT 4.0 system will not see this new device. Even if you send an IOCTL_SCSI_RESCAN_BUS call by running Disk Manager, the new device will not be found because of the problem with the Scsiport.sys driver.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K