I've been using Linux for for 4 years, but not a core user.

Here's What I've really wanted to know about root permision

I will really appreciate if you tell me what is going on exactly.

As far as I concerned, a normal user is not allowed to perform system tasks such as system shudown, accessing to root permission folders, disk mount, and things like that..

however,

1. I shutdown my computer using Gnome menu. Nontheless, Gnome is logged on with my account(not root) It does shutdown my computer.

2. Once I plugged in my usb drive, it automatically shows up on my desktop. I tried to mount the usb on the command line, but I was required to attain the root permission.

3. Eclipse (running with my account) properly executes Apach tomcat server, As number 2, I couldn't execute apach tomcat server without root permission.

4. The most irregular case. I usually update Eclipse plugin by using update menu in the Eclipse. I strongly believe that should not work since, the Eclipse is working with my account and the task is required to access to /usr/lib/eclise. Amazingly, sometimes it does work! and occasionally it does not work!


Please tell me answer to my questions

I'm not sure about the third and forth question. However the desktop manager is started during init, (the runlevel for GUI depends on the distro. Often runlevel 4/5?) so it is started as root. Atleast kdm wont start as an other user then root.
The mounting of devices in a desktop environment (DE) isn't done by any user. As you may have noticed, the user logged in on a DE has to be member of three groups to be able to use the automatic mounting. hal, dbus and messagebus. So therefor it's a program running as root that does the actual mounting, the user only "agree". That's the way I think it works. I have no in depth knowledge of how this works, but since everyone else quiet, I gave it a shot. Since I've had some filthy water, I might not be aiming to well.

1) It's something that's on by default on most distros, in that if you are doing a local login (thus, actually sitting at the physical computer), you can control the power on/off status. Probably because if you really wanted to, you could just unplug the computer, so why force them to go that far? From command line, it's a restriction as you could be logging in from SSH/telnet, and be any user. Could take several hours, or even days, before somebody could get to the server and turn it back on.

2) This is, again, the fact that you're sitting at the computer. That, and to make Linux more usable to the common person. If my bit of knowing how to enable it on Slackware is common, users are added to a specific group that allows users access to these drives. How they are auto-mounted I'm guessing is a series of daemons monitoring dmesg to find out when there has been a hardware change, and acting on it.

3 & 4) Only ever used the basic Apache HTTPD server, so I don't know about Tomcat, and for plugins, only ever installed CDT, which I did as root. Check out the permissions for Eclipse (ls -l /usr/lib/eclipse). Permissions are displayed like rwx-r-xr-x, (read, write, execute grouped for UUUGGGOOO, user, group, others). If others have write permissions, then that would explain why you can. if not, then I've got nothing.