Test Storage Media with f3write/f3read

This translation was generated automatically.

An old pick from Bits und so #294, but worth repeating.

You should check newly purchased SD cards, USB sticks, and similar storage for their real capacity and reliability before recording irreplaceable data—even if they came from a seemingly reputable source. Scammers keep selling devices whose packaging and configuration claim a false capacity. Your camera may happily write 32 GB to a card that actually holds only 1 GB. Then the data is gone. The card may also simply be defective or unable to sustain its advertised write speed.

For obscure operating systems, there’s h2testw from Heise. On a Mac, use f3write / f3read. The tool fills the drive with a verifiable pattern and then reads it back.

$ ./f3write /Volumes/NO\ NAME/
Free space: 29.49 GB
Creating file 1.fff ... OK!
Creating file 2.fff ... OK!
Creating file 3.fff ... OK!
...
Free space: 0.00 Byte
Average writing speed: 7.78 MB/s

$ ./f3read /Volumes/NO\ NAME/
                 SECTORS      ok/corrupted/changed/overwritten
Validating file 1.fff ... 2097152/0/0/0
Validating file 2.fff ... 2097152/0/0/0
Validating file 3.fff ... 2097152/0/0/0
...
Data OK: 29.49 GB (61835072 sectors)
Data LOST: 0.00 Byte (0 sectors)
Corrupted: 0.00 Byte (0 sectors)
Slightly changed: 0.00 Byte (0 sectors)
Overwritten: 0.00 Byte (0 sectors)
Average reading speed: 17.99 MB/s