I have tried different OSes and found 'root' or 'Administrator' account in every system. Which is usually disabled by default. So what is purpose of this account? Why would we need this account? At what time it is created in any OS? If a 'root' account is necessary then why it is necessary, at what time OS use it?
closed as too broad by Anthon, Archemar, Networker, John WH Smith, jordanm Apr 2 '15 at 13:16
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That you found a
Adminstrator account in every OS you looked at is just coincidence (or maybe a result of being new to this all). You don't need that kind of super-user in an OS and many OS don't have such a user or any concept of user at all. e.g. MSDOS.
If you (as the OS manifacturer) want to prevent all programs from doing everything without restriction, you need some way to require and allow privileges. There are many ways of doing this (flipping a switch on the front panel of a computer, inserting a card, logging in with super-user credentials).
The checks for this should be build into the OS. But the actual activation can be made depending on the circumstances. At install time, at activation at the users site, whatever is convenient, (or what the customer expects).
Not having a super-user (or other means to limit access to potentially destructive operations) can be considered user unfriendly as there is nothing between starting a (downloaded) program and it wiping your whole disk.
You don't need such a super-user, but once the mechanism is there (and correctly installed) you are better of using it. But then in order to elevate the privileges when circumstances require it you need some mechanism to check whether you are allowed to do get this "elevation". Logging in as root does the trick and is software only. If every computer in the world would have a switch on the front of the machine for super-user mode (not so secure if someone has physical access to your computer), or a secure-card slot and corresponding card, that could be used as a generic mechanism as well (but it would be difficult to download such a secure-card together with the installable ISO of your Linux, and thus less convenient).