Mac surface scan tool I've had an SDcard lose its partition table, so I want to run a surface scan of the sdcard to make sure it's physically okay. Can you suggest a disk surface scan tool that runs on the Mac? Free, preferably. Thanks.
One of my favorite Mac developers released just the tool for your task.

It's called stressdrive and writes the entire drive with data and reads it back to ensure every bit was readable and matches what was written.