STATUS
Rescanning of nonzero LUNs requires two things:
- Install WinNT 4.0 Service Pack 3 (or later) version of Scsiport.sys.
and
- a LunRescan value added to the Disk key.
After these two things are in place, IOCTL_SCSI_RESCAN_BUS should find
nonzero LUNs. The value under the Disk key is used even if the system has
no disk devices installed.
Note that ScsiPort.sys will only find consecutive LUNs with the LunRescan
registry entry, starting from LUN 0 up to the maximum LUNs supported on
the device. As soon as a LUN does not respond, ScsiPort.sys stops
scanning. For example, on a system with LUN 0, LUN 1, and LUN 5
responding, only LUN 0 and LUN 1 will be recognized. This behavior is
by design.
To add this value to the Disk key, perform the following steps:
WARNING: Using Registry Editor incorrectly can cause serious problems that
may require you to reinstall your operating system. Microsoft cannot
guarantee that problems resulting from the incorrect use of Registry Editor
can be solved. Use Registry Editor at your own risk.
For information about how to edit the registry, view the "Changing Keys And
Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete
Information in the Registry" and "Edit Registry Data" Help topics in
Regedt32.exe. Note that you should back up the registry before you edit it.
- Start Registry Editor (Regedt32.exe), and go to the following subkey:
\\HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Di - Add the following value to the Disk key:
Value name: LunRescan
Data type: REG_MULTI_SZ
The Data for this value can be left NULL and the IOCTL rescan will apply to
all devices. To specify a specific device, the string in the value should
match the device(s) Inquiry string. Only the matched string should be
rescanned when the IOCTL is issued, but the SCSIPORT SP3 implementation
does not limit rescan to only the specified device. However, this might
change in a future release.
After this key is added, a reboot is NOT required. The
IOCTL_SCSI_RESCAN_BUS should now search the nonzero LUNs.
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):