Howling:Greetings, Could anyone explain the "Time Lock" in The End Of Time , please?

Hello, I am watching The End Of Time, and i'd love to know more about the "Time Lock" from which the Time Lords Council{?} is operating ... ANY wee piece of information would be appreciated... like: What IS a time lock? Is this the only one we've seen? How and when was it created~ does the Doctor know about it (or did he create it in the time war?)? Who is in This One? Does time pass like ours within the Lock? Etc.Etc.... i could not find an entry on just the lock, so any information or links would be Very Much Appreciated! You guys do a fabulous job at reaching out to fans and particularly at being kind to to those of us just getting on board with both the classic and the new series...it's nice not to feel like an 'idiot outsider'. Thank you...'I Want To Know More'! S from VT