32-Bit File Access Can Cause ScanDisk to Report Harmless Error (107651)
The information in this article applies to:
• Microsoft Windows for Workgroups 3.11
• Microsoft MS-DOS operating system 6.2
• Microsoft MS-DOS operating system 6.22
This article was previously published under Q107651
3.11 | 6.20 6.22
WINDOWS | MS-DOS
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After you run Windows for Workgroups version 3.11 on an MS-DOS 6.2
DoubleSpace-compressed drive or an MS-DOS 6.22 DriveSpace-compressed drive
with 32-bit file access enabled, the MS-DOS ScanDisk utility may report the
following error when run at the MS-DOS command prompt
where <nnnn> equals the number of bytes of lost files or directories,
and <x> equals the logical drive ScanDisk was scanning.
NOTE: ScanDisk should not be run from the MS-DOS command prompt within
Microsoft Windows or Windows for Workgroups. It should be run directly from
MS-DOS. If you must run ScanDisk from within Windows, use the /CHECKONLY
switch. This switch prevents ScanDisk from attempting to repair any damage
while Windows is running.
This error message is caused by a problem in Windows for Workgroups 3.11.
32-bit file access writes buffers in the order they are used, meaning the
first information into the buffer is the first information out. 32-bit file
access also tries to improve access speed by finding contiguous used
buffers and writing them together. If these two optimization schemes both
try to clean the buffer simultaneously, an erroneous extra entry in the
DoubleSpace or DriveSpace file allocation table (MDFAT) can occur.
This problem can also occur when 32-bit file access flushes the entire
volume. Buffers are written sequentially according to their physical
location. This optimization has no effect on a compressed volume (since
there is no physical-to-logical relationship) and can result in erroneous
entries in the MDFAT.
No saved data is lost. However, data in memory only at the time of the
error message may be lost. If you choose to correct the problem, ScanDisk
repairs the volume and creates the standard CHKDSK files (FILEnnnn.CHK),
which can be deleted. ScanDisk may also report that there are sections of
the DoubleSpace or DriveSpace volume not being used by any files but
marked as unusable; it can repair these as well.
Microsoft has confirmed this to be a problem in Microsoft Windows for
Workgroups version 3.11. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.
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