VERIFY ON, COPY /V, XCOPY /V Commands Do Not Compare Data

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Article ID: 126457 - View products that this article applies to.
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SUMMARY

Some versions of the MS-DOS "User's Guide" and online Help indicate that the /V (verify) switch for the COPY and XCOPY commands actually compares the source and destination files to determine whether they are identical. This is not correct. The /V switch verifies that the destination file, once written, can be read. No comparison of the files occurs.

This information also applies to the VERIFY ON command.

MORE INFORMATION

When you use the VERIFY ON command, or the /V switch with the COPY or XCOPY command, the MS-DOS file system uses the block device driver command code function 09H, Write with Verify. This verification process consists of confirming that the data just written can be read (for example, that the data was not written to a bad sector on the disk). No comparison of the source and destination data occurs.

To compare the source and destination files, use the MS-DOS FC (file compare) command after you use the COPY or XCOPY command.

REFERENCES

For more information about the VERIFY, COPY, XCOPY, or FC command, see your MS-DOS "User's Guide," or use the online Help in MS-DOS versions 5.0 and later.

"Advanced MS-DOS Programming," Ray Duncan, Microsoft Press, Chapter 14, pages 267-276

Properties

Article ID: 126457 - Last Review: May 6, 2003 - Revision: 2.0
APPLIES TO
  • Microsoft MS-DOS 3.1
  • Microsoft MS-DOS 3.2 Standard Edition
  • Microsoft MS-DOS 3.21 Standard Edition
  • Microsoft MS-DOS 3.3 Standard Edition
  • Microsoft MS-DOS 3.3a
  • Microsoft MS-DOS 4.0 Standard Edition
  • Microsoft MS-DOS 4.01 Standard Edition
  • Microsoft MS-DOS 5.0 Standard Edition
  • Microsoft MS-DOS 5.0a
  • Microsoft MS-DOS 6.0 Standard Edition
  • Microsoft MS-DOS 6.2 Standard Edition
  • Microsoft MS-DOS 6.21 Standard Edition
  • Microsoft MS-DOS 6.22 Standard Edition
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KB126457
Retired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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