Microsoft KB Archive/834160

= NTBackup may not detect corrupted backup files during verification =

Article ID: 834160

Article Last Modified on 12/3/2007

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APPLIES TO


 * Microsoft Windows Small Business Server 2003 Premium Edition
 * Microsoft Windows Small Business Server 2003 Standard Edition
 * Microsoft Windows Server 2003, 64-Bit Datacenter Edition
 * Microsoft Windows Server 2003, Enterprise x64 Edition
 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Web Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Datacenter Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Server

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SYMPTOMS
When you use NTBackup to create a backup of your Windows 2000-based computer or server, NTBackup may not detect some forms of corruption or damage in the backup files during the verification pass.



CAUSE
This behavior occurs because the verification pass uses a checksum comparison to determine if there is corruption in the backup files. The checksum algorithm uses a word-wise exclusive OR operation (XOR) comparison of the backup data. If corruption occurs in the data at the same location in a word an even number of times, the checksum algorithm cannot detect this corruption.

NTBackup uses the word-wise XOR algorithm for compatibility with the Microsoft Tape Format (MTF) specification. Section 5.1 of the MTF specifies the use of this algorithm.



STATUS
This behavior is by design.

Additional query words: Win2000 Win2k

Keywords: kbbackup kbnofix kbbug KB834160

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