Locations of the files on volume are expressed in number of clusters, while the same locations on the physical disk should be expressed in sectors. During normal filesystem operation, number of sector containing file data is computed from the number of cluster by the following simple formula:

 

 

where  CF (Cluster Factor) is number of sectors per cluster and SS (Start Sector) is a sector number for cluster 0.

 

When  volume is damaged, values of CF and SS are usually lost or corrupt, so they are determined statistically based on pattern scan results. Best matching values are listed in the table along with their corresponding relevance values. Additionaly, "Boot Sector" column indicates if a boot sector matching the parameter set was found on the disk.

 

In the above example, first parameter set is obviously good because it is three times more relevant than the second one (72.7% vs. 21.4%) and has a corresponding boot sector ("Good" mark in "Boot sector" column).

In some cases it is impossible is to determine proper volume parameters, and the list would be empty. If you see nothing in the list, check scan area definition and filesystem type. If scan area is properly defined but program is still unable to detect volume paramters, the volume is usually damaged beyound any automatic repair. If you know a parameters set you may try to specify volume parameters manually. To do so, click "Manual", and enter volume start sector and number of sectors per cluster into appropriate fields.