Overlapped I/O to Tape Results In Data Corruption

 Last reviewed: September 7, 1996
Article ID: Q150302
The information in this article applies to:
  • Microsoft Windows NT Workstation version 3.51
  • Microsoft Windows NT Server version 3.51

SYMPTOMS

Data corruption occurs when you write data to the Windows NT 3.51 tape drivers using overlapped I/O. The Windows NT backup program NTBackup.exe does not support overlapped I/O, so this problem only affects developers writing third-party backup software for Windows NT.

CAUSE

The data corruption occurs because the tape drivers do not zero out the QueueSortKey in the SCSI Request Block (SRB) before submitting the SRB to the SCSIPort driver. As a result, random values are placed in the QueueSortKey, causing overlapped writes to be committed to tape out of order.

RESOLUTION

Change the tape drivers to set the QueueSortKey to zero before submitting write requests to the SCSIPort driver.

STATUS

Microsoft has confirmed this to be a problem in <product and version>. This problem was corrected in the latest Windows NT 3.51 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

KBCategory: kbnetwork
KBSubcategory: ntutil NTSrvWkst
Additional reference words: 3.51 prodnt

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Last reviewed: September 7, 1996
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