Versioning

• ext3cow. http://www.ext3cow.com/ - "enhanced version of ext3 that allows one to take a snapshot of one's file system, with one second granularity, freezing the way the file system looked at given point-in-time"
• InfoMonitor - Cooper, Brian F., and Hector Garcia-Molina. "InfoMonitor: Unobtrusively Archiving a World Wide Web Server." International Journal on Digital Libraries 5, no. 2 (2005): 106-19.
  http://www.brianfrankcooper.net/pubs/fmpaper.pdf
• Revision Control System (RCS)- "automates the storing, retrieval, logging, identification, and merging of revisions. RCS is useful for text that is revised frequently, including source code, programs, documentation, graphics, papers, and form letters"
  http://www.gnu.org/software/rcs/rcs.html or http://www.cs.purdue.edu/homes/trinkle/RCS/