wonderful, thanks!

I'm certainly getting the impression that this is a rather different beast than the linux I am used to.

so one last question: can you please review these definitions/assertions, and tell me if I am wrong somewhere?

1) flashing: the process of replacing the rom (os) of the device. does not affect userspace storage.

2) unlocking: the process of reconfiguring mount attrib for the system partition to RW mode.

3) rooting: the installation of tools to control access to systemspace resources (files on /)

4) custom recovery: utilies for backing up the rom to the device or remote storage, and for restoring from the backups at boot time.

5) unlocking bootloader: needed to change to new flavor of rom, but not needed to run rooted stock version. once unlocked, may not be able to be relocked effectively, because of hardware switch.

6) fastboot: a bios like startup menu from which you could access custom recovery utils.

7) factory reset does not live on the device, so an initial stock backup is required if you ever want to go back to stock.

that sound about right? I'm suprised at how much there is to learn on this topic, and I'll feel much better once I have the knowledge and confort to always be able to bring my device back to stock, no matter how I abuse it.

Thanks again

ok, that answers many questions. I had assumed 'su' was a reference to the *nix Switch User command (which is sometimes incorrectly called 'superuser', because its most commonly used to switch to the root user's shell). this SuperUser app sounds more like sudo or UAC.
 
so, does SuperUser ask the user for permissions when a restricted action is requested, or do you have to instruct the app to run as root?