scan storage media for bad or near failure sectors

 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.