It depends what you want to save. The data is in various folders, I would not recommend a total backup to transfer to a second audya as it will render any post 2010 copy protected material useless (eg styles). Same happens if you illegally download a disk image.

Most are located in obvious places (registrations in the registrations/singles folder for example)

programs are a little more tricky. When you 'save to disk' it saves in the 'user data' folder and from there you can load it into a slot in your program section. If you want to save the entire program bank its in the system/init/ folder and is programs40a.prg (or something similar)

If you list the things you want to back up i'll tell you the locations next week. (having a weekend off!)