PS3 HD formatting

I'm looking to format my HD, but have a few questions...

1) Currently, I have 5 bought games. If I backup my HD and then format it will the backup "backup" my bought games too?

2) Does it back up gamesaves?

3) Does it back up firmware?

The reason I want to format is because I set aside about 15 gigs for Linux and I don't use it anymore so it is just using up my HD...