courthouse security

[keith in RI]

i wanted to start this because i remember during the browns supporters trials last year there was a big bru-ha over the marshals at the federal courthouse in concord suddenly asking for drivers licenses from anyone before they would be allowed to enter.  i remember when i entered the court there in concord they looked at my license and then wrote down all the info on it (which raises a question of what do they do with that info, how long its kept etc?) into a little notebook on the desk. well when i went to federal court here in providence rhode island on friday for another friends trial the courthouse security here was drastically upgraded from a little notebook. before i went there i checked the website for the r.i. federal courthouse and it said they participate in the 100% total security program at courthouses and that everyone needed identification to enter the building. when i arrived  i noticed they didnt just check your id and write it down, the desk had an entire computer on it with all kinds of scanning equipment. they scanned both the front and back of all drivers licenses into their computers (even if the back is blank) and then appeared to save a copy of the image onto the hard drive. my question is what do they do with this information?? why do they need to know WHO entered the courts?