iPhone Restore and Format

Hello FF - newbie to posting

I have a couple questions regarding the iPhone restore process.

Exactly what happens when the iPhone is restored through iTunes, i have seen many references saying that the System partition is formatted in order to install the new firmware, but i have found that the level of format seems to differ accross the version of iPhone. Some models will do a full format, others will just do a quick format.

Is there any links out there that document the steps taken by iTunes and maybe even the format commands used?

Thanks in advance for any help
Lewis