I may have made an incorrect assumption - what exactly is "-current"?

I had thought it was fixes to the 1.6.2 chain, but unreleased.  Is
"-current" actually the same as the 2.0 release?

I ask because I downloaded both the -current and 2.0 "daily" compiles
yesterday, and tried to install them.

2.0 hard-locks on mounting a CF card, and when it boots, shows "2.0G".

When I try to install -current, it also boots showing "2.0G", and while
it doesn't lock up mounting a CF card, it "runs out of space on /", and
drops into the debugger.

So - what is -current in relationship to 1.6.2 and 2.0?