Article ID: 83140 - View products that this article applies to.
This article was previously published under Q83140
When two (or more) files are cross-linked on the same cluster, do the following:
NOTE: If you are running MS-DOS 6.2 or later, run ScanDisk, instead of using the following procedure.
What Are Cross-linked Files?MS-DOS organizes the disk's data area into sections called clusters or allocation units. Each file has its own directory entry, which includes the file name, size, attribute information, date, time, and the cluster where the start of the file is stored.
The file allocation table (FAT) includes an entry for each cluster. Each cluster's entry includes either a code specifying that it is the last cluster in the file, or the number of the next cluster used by the file. Clusters can also be marked unusable, which CHKDSK reports as bad sectors.
Cross-linked files occur when two or more files are both marked as "owning" the same cluster. Usually, the last file updated is correct; the other is correct except for the cluster's worth that is part of the other file.
For example, suppose you have two files, each 512 bytes in size. Each file requires one cluster. If both files are marked as being located in cluster 5, then cluster 5 probably contains the file with the later date. You can confirm this by looking at it (if it's a data file) or running it (if it's a program).
How Are Cross-linked Files Fixed?The only way to fix the FAT in this case is to delete BOTH files. When you delete the file, each cluster assigned to that file is marked "free to be used." If only one file is deleted, the cluster on which the cross-link occurred is marked unused, but the file system still shows that cluster as belonging to the "good" file. This causes another error (for example, CHKDSK may report a file allocation error, size adjusted or file allocation error, or file truncated). You also lose access to the file from the part that was stored in the beginning of the cross-linked cluster to the end of the file.
MS-DOS should be able to make a copy of both files (although one will probably be corrupt). If you don't want to delete both files, copy them to a floppy disk or another subdirectory before deleting them.
Article ID: 83140 - Last Review: May 10, 2003 - Revision: 2.0
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