f3read

Validate a device by checking the files in a given directory

$ f3read [path/to/mount_point]

f3read [options]

    The directory where the files created by f3write are located.

--time-ops
    Measure and print the time of read operations.

f3read is a command-line utility designed to verify the integrity of flash memory cards (such as SD cards and USB drives). It's part of the F3 (Fight Flash Fraud) suite. It reads data files written by the f3write command and checks if the data read back matches what was originally written. This helps detect fake or faulty flash memory cards that report a larger capacity than they actually have. If the flash drive is defective and corrupting data, f3read will report errors, detailing which files and sectors are affected. By writing known data patterns with f3write and then reading them back with f3read, you can identify the true usable capacity and reliability of a storage device. It's crucial for avoiding data loss and ensuring the advertised capacity of flash storage is genuine. This is useful for consumers buying flash memory cards and want to check for quality.

f3read relies on the files created by f3write. If those files are corrupted outside of the F3 tools, f3read may produce misleading results. Always run f3write first. Also, f3 tools may take a considerable amount of time to finish due to large data that must be read and written.

f3read returns 0 on success (all data verified correctly). It returns a non-zero value if any errors were detected during the read verification process. This allows for scripting and automated testing of flash storage devices.

F3 (Fight Flash Fraud) was developed to address the issue of counterfeit or mislabeled flash memory devices, particularly SD cards and USB drives. The initial development was driven by the need to verify the true storage capacity and reliability of these devices. The f3read command is a core component of this suite, providing the read verification functionality that complements the write operation of f3write. It's been used extensively by consumers and system administrators to validate storage devices, particularly in situations where data integrity is critical. Development continues to improve accuracy and efficiency.

f3write(1), f3probe(1)