Corporations have long had a variety of methods for backing up data in real time. Naturally, a lost document after a day's work can be more than you would like to put at risk. IBM is selling a program that can backup files continuously to either a network drive or to a USB flash device. The specs look good and IBM certainly has a good reputation in the data protection/recovery market. Worth taking a look.
IBM Tivoli Continuous Data Protection for Files - Product overview: "Continuously back up crucial corporate data on file servers and transiently connected machines"