diskscan - 0.21-1+b1 main

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.
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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.
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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.