This question already has an answer here:
Let's say I had a 60GB Playstation 3, and I bought a new 500GB hard drive to replace the old one. I take the 60GB hard drive out of the machine, put the 500GB one in, format it, and get started and..
"Oops! I forgot to back something up from the old hard drive!"
Can I take the 500GB hard drive back out and put the 60GB drive back in (remember, this is the same console; not a new one), and will it still recognize the old drive properly so I can perform a backup?