f3 to test hundreds of USB flash memory sticks for errors.
Here's an example output from a faulty drive. First writing test files with
Free space: 3.74 GB Creating file 1.h2w ... OK! Creating file 2.h2w ... OK! Creating file 3.h2w ... OK! Creating file 4.h2w ... OK! Free space: 0.00 Byte Average writing speed: 2.22 MB/s
Then reading back with
SECTORS ok/corrupted/changed/overwritten Validating file 1.h2w ... 2030944/ 0/ 0/ 66208 Validating file 2.h2w ... 2032136/ 0/ 0/ 65016 Validating file 3.h2w ... 2031920/ 0/ 0/ 65232 Validating file 4.h2w ... 1509112/ 0/ 0/ 48376 Data OK: 3.63 GB (7604112 sectors) Data LOST: 119.55 MB (244832 sectors) Corrupted: 0.00 Byte (0 sectors) Slightly changed: 0.00 Byte (0 sectors) Overwritten: 119.55 MB (244832 sectors) Average reading speed: 3.23 MB/s
Typically if a USB drive contains errors, they come up in the corrupted column. Recently I've got drives that report errors in the "overwritten" column. I wonder what is the difference between the three.
I've also noticed that
badblocks utility also reports errors in three columns, I wonder if it's the same scheme? EDIT: not it's not - How to interpret badblocks output