Quote:
Assuming that the fsck program on the player supports it, you can pass the '-c' switch to fsck.ext2, which will cause a read-only block test. If you pass it twice, you get a non-destructive read-then-write test.

Fsck does this by running the "badblocks" program, which you can also run directly. But badblocks looks for individual sectors with hard errors, which is not the problem you have -- or at least, not the main problem. Your experience with the song that wouldn't re-play says that a sector which read right the first time, failed the second time. Running badblocks on AC power won't diagnose whatever it is (heat? vibration? bad solder joint?) that makes the whole drive sporadically cease to exist (from the player's point of view) when in the car.

Peter