NTFS Documentation: $BadClus

Definition

This is a system file that contains all the bad clusters of the volume. This forces the data attribute of this file to be non-resident.

Layout

All the bad clusters of the volume.

Note: Actually, we don't care about the stream of the data attribute, because it is never read or written. Only the runlist of the data attribute matters.

Interest

A cluster is bad if it contains at least one bad sector. Because this system file works as any other file, all the bad clusters are marked as used in the $Bitmap system file, so they can never ever be used by any other file.

NTFS support hot-fixing: no more FAT's "Abort, Retry, Fail?". If a new bad cluster is found while the system is running, it is silently added to this file. If the cluster was on a fault tolerant volume, ftdisk (the fault tolerant volume driver) reconstitutes the data and NTFS stores them in another free cluster.

Regis Duchesne

Last modified: Sun Feb 14 15:05:39 PST 1999