Diskscan is intended to find sectors of a storage medium (hard disk, flash drive or pendrive, etc.) which are bad or in the process of going bad.

The operation is entirely read-only and does not cause damage to the data on filesystems. As the program reads block device sectors, it will work whether there is a filesystem or not.

diskscan reads the entire block device and notes the time it took to read a block. When there is an error it is immediately noted and also when there is a higher latency to read a block. A histogram of the block latency times is also given to assess the health of the medium.

diskscan can also be used to test the speed and quality of the medium. All sectors of a perfect medium could be read at the same speed.