OK, beta9 had some problems. Here's some information you might find useful though:

1. Upgrades are applied to a completely different partition. It doesn't matter how much space you have on your music partition.

2. Yes, we do plan to make emplode keep track of disk space. I was hoping to get it into beta9 but it didn't make it :-(

3. The problems you were seeing in beta9 may not have been due to your disk being close to full. The consumer version of beta9 was inherently unstable due to memory overcommitment. I notice you were later running the developer version though.

4. You can use 'rwm' and 'rom' to switch between the disk being mounted readwrite and readonly without unmounting it.

--
Mike Crowe
I may not be speaking on behalf of empeg above :-)