Originally Posted by garak

The internal drive is 300GB. Of that 100GB is reserved for use by the HR20, 200GB is how much space you can use for your recordings.

I'm actually using a 500GB drive inside an esata enclosure. This actually doubles the recording time (100GB reserved, 400GB user space).

You can plug and unplug the external drive as you like (just do it only when the HR20 is unplugged from the power socket).

The external drive is NOT reformatted when plug it in (except the very first time it's plugged in) so you won't lose the recorded programs on the external drive if you unplug it, then plug it back in.

Actually you should do a search of this forum. This topic was discussed to death January of this year