Some DEC TLZ06 4MM DAT Tape Drives Not Recognized by Windows NT

• Microsoft Windows NT Workstation versions 3.5 and 3.51
• Microsoft Windows NT Server versions 3.5 and 3.51

SYMPTOMS

After you install the 4 millimeter DAT device driver, if you are using a Digital Equipment TLZ06 4MM DAT tape drive, you may receive the following error in the event log:

   Event ID: 7026
   Source: Service Control Manager
   Description: The following boot-start or system-start driver(s) failed
   to load:
             4mmdat.sys

CAUSE

The identifier string embedded in the tape drive's firmware was changed to read DEC TLZ6, but the 4mmdat.sys device driver is looking for a string of DEC TLZ06--this difference in identifier strings prevents the driver from recognizing the tape drive.

To verify that this is the problem, use Registry Editor to look at the firmware's identifier string as follows:

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.

1. Run Registry Editor (REGEDT32.EXE)

2. From the HKEY_LOCAL_MACHINE window, go to the following key:

         \Hardware\Devicemap\SCSI\SCSIport(x)\ScsiBus(Y)\Target(z)
   

   where x= the scsiport number that the tape drive is attached where y= the scsibus number that the tape drive is attached where z= the scsi I.D. number that the tape drive is configured for.

3. Look at the identifier value found under the tape drive's target(z) number. If the identifier string does not read:

         DEC TLZ06
   

   but instead reads DEC TLZ6, this is the cause of the device driver failure.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.5.x We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

The TLZ06 4MM DAT tape drive is manufactured by Digital Equipment Corp., a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product’s performance or reliability.