Premium means that you bought minecraft, not playing it for free. Some servers require premium status to play on.
If you mean to buy minecraft, go to Minecraft.net and click the big orange "Get Minecraft!" button. If you mean on a server, it depends on which server you go to. Most servers have websites.
You can join any server, no matter what type of computer you're using. If you mean do you have to have the same mods as a modded server to join, yes, you do.
To join a game server (if thats what you mean) you have to be a member of xbox live. You must get "Gold". Then you put in a game with an online feature (like Minecraft or Call Of Duty) and join an online server/game.
it means the server has gone down such as minecraft server has crashed or the server owner has lost Internet connection
Well duh I mean like 95% of all minecraft users get on a server some time in their lives if it is not all they play... so YES it is "safe to go on an open server on minecraft."
if you mean minecraft servers well they are hosted by different people any one can host a minecraft server.
It means the server hasnt updated to a newer version of the game.
You don't donate on minecraft, you buy the game, which then regesters your minecraft username to be a account that has bought the game. If you mean how do you donate to a specific minecraft server, then go onto the server website, and they will probbaly have a DONATE button.
either you don't have An internet connection or you have a cracked account on minecraft and it wont let you on. The alternative to this is their minecraft server was having issues.
it means that the server is either turned off, or is encountering problems
It means the server is using an old version, older than the version you are using.
It means someone is screwing with you. Or the server requires you to somehow become a wizard.