So I order a lot of stuff online. Sometimes, SD cards and USB drives can be counterfeit or scams. For example, they might change the firmware to report “64GB” but it’s really just a 2GB or smaller. At first use, it seems to work fine, but once you start trying to fill up the device with actual data, it will fail.
So the first thing I do when get a shipment of new devices is test the read and write performance and capacity.
I use a program called f3 – Fight Flash Fraud to do so. You can install it with apt-get on any Debian Linux Distro, and it’s in the Mac Homebrew repository as well.
Here it is in action.
It writes big files to the device, and then verifies that they were properly written, all the while reporting on the performance of the device.