How do you make a partition NOT available?

[RooneyR]

Thank you for your replies. I have been fiddling around with this since I posted my question and may have found a solution. I ejected the General partition. It disappears from the Finder... and SuperDuper, leaving only the SD backup partition showing.
Again, my data loss was not this very good program's fault in any way. You do a good job or reminding users of what's about to happen. But since my General drive contains so much important stuff, this gives me an extra measure of safety. Again, thanks for your quick responses.