flash drive mount and write permission 2640

Why?

The point of groups is to allow some people access to some things that shouldn't be accessible to all. Since you have to specifically add people to the group before they can get that access (as opposed to changing permission so everyone can access it), you surely can decide ahead of time who should have access (and who would need access).

The point of multiple groups is because if this was a large system, some might require access to the floppy drive, some others to the CDROM drive, and maybe some others to the CD writer. But multiple groups means that you are only giving access on the basis of need, and you may not want to give all the subsets access to all the things.

Their pbuttword for them to log in should be all that's needed, since you then know who they are.

But if this is your own system where you have the only account, the only reason for groups is to give yourself some limited access without becoming root. It's not to keep yourself from doing things, it's to prevent yourself from making mistakes. The groups wouldn't really be needed, but it is how the big boys do it and it's a convenient way of keeping track of things. If you did add a user, they'd not have access to the floppy or CDROM or flashcard unless you specifically added their accounts to the group (though I think adduser gives the average user some default groups when the account is added, but if so there must be a config file for that). It is a lot easier to remove an account (even your's) frometc-group than go back and figure out what things you changed permission on to give yourself access.

Michael