attempting to overfill neuros "hangs" synchronization

I told positron to sync a directory with (links to) about 200M worth of mp3's
into the 128M neuros.

It got about 120 megs in and crashed with an uncaught exception - no space left
on device.

I had to remove the neuros from the backpack - it wouldn't unmount, it wouldn't
respond to the controls - it was dead.

Positron should deal with this more gracefully.