what is the field of study called where you use programs/commands to retrieve data off hard drives that is marked gone but still s there, backtrace ips, etc. Sorta like fbi agents do with terrorist/criminal computers. Dunno if you ever saw 24 but sorta like chloe and edgar do when they need get info off other computers and run stuff see their activity and stuff. I'm trying to figure out what to study. I'm looking into purchasing a book to learn.