Trying to see a difference between
 

using the Sandbox thing and just making a backup of the Boot drive prior to installing any updates.

Originally I thought that using sandbox meant that I'd always have a copy of my files on each drive. That way if a drive dies I'd never lose anything. But I think it says that the files are only stored on the main drive and accessed by the Sandbox drive. That means that if my main drive goes bad I do not have copies on the Sandbox drive.

It seems like backing up before updating would give me the benifits of Sandbox and also have files on a different drive.

Am I way off here ?

A backup is both more and less than a Sandbox. You can't substitute one for the other.

You'll want a full backup. But, when installing updates, you can try them out on the Sandbox. Even if you run for a while and make changes to your files, you can "uninstall" the update by simply booting back to your original drive. All your user files changes will still be there -- which isn't true with a backup.

Make more sense?

OK, having both a Back-Up & the Sandbox makes sense.

Is it correct that my files are only stored on the Main drive and the Sandbox drive accesses them there?

Thanks

That absolutely right; that's why we say you have to back up the main drive, not the Sandbox.

One final question, (probably not)
 

Why do you call it Sandbox ?

Because it's a "safe place to play".

It's too bad that phrase isn't quoted in the User's Guide section on creating a Sandbox - it kind of helps to understand the concept and its purpose. Also, it's cute. Dale Meyn.

Maybe in a future manual revision... :)