4.4 Mbadblocks

The mbadblocks command is used to mark some clusters on an MS-DOS filesystem bad. It has the following syntax:

mbadblocks [-s sectorlist|-c clusterlist|-w] drive:

If no command line flags are supplied, Mbadblocks scans an MS-DOS filesystem for bad blocks by simply trying to read them and flag them if read fails. All blocks that are unused are scanned, and if detected bad are marked as such in the FAT.

This command is intended to be used right after mformat. It is not intended to salvage data from bad disks.

4.4.1 Command line options

c file

Use a list of bad clusters, rather than scanning for bad clusters itself.

s file

Use a list of bad sectors (counted from beginning of filesystem), rather than trying for bad clusters itself.

w

Write a random pattern to each cluster, then read it back and flag cluster as bad if mismatch. Only free clusters are tested in such a way, so any file data is preserved.

4.4.2 Bugs

Mbadblocks should (but doesn’t yet :-( ) also try to salvage bad blocks which are in use by reading them repeatedly, and then mark them bad.