Thanks to all for the responses. I guess it is a drum sander and not a
belt. These items look like what was in the store...

http://www.homedepotrents.com/diyTools/floor_sander.asp
http://www.homedepotrents.com/diyTools/drum_sander.asp

If I tried the drum sander what grit would be safe for my initial
"education period" with less chance of doing damage? I guess I'd be ok
if I just kept the unit in constant motion? Will the drum sander use
less paper? If I went with the safer orbital what would be appropriate
starting grit for removing one layer of old varnish? Thanks again.