VERIFY ON, COPY /V, XCOPY /V Commands Do Not Compare Data (126457)
The information in this article applies to:
- Microsoft MS-DOS operating system 3.1
- Microsoft MS-DOS operating system 3.2
- Microsoft MS-DOS operating system 3.21
- Microsoft MS-DOS operating system 3.3
- Microsoft MS-DOS operating system 3.3a
- Microsoft MS-DOS operating system 4.0
- Microsoft MS-DOS operating system 4.01
- Microsoft MS-DOS operating system 5.0
- Microsoft MS-DOS operating system 5.0a
- Microsoft MS-DOS operating system 6.0
- Microsoft MS-DOS operating system 6.2
- Microsoft MS-DOS operating system 6.21
- Microsoft MS-DOS operating system 6.22
This article was previously published under Q126457 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
| Modification Type: | Major | Last Reviewed: | 5/6/2003 |
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| Keywords: | KB126457 |
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