Lead-up

• pre-1972: cp
• 1972: SCCS
• 1982: RCS
• 1991: Aegis
• 1992: CVS
• c. 1995-1999: ClearCase (non-free)
• BitKeeper (non-free)
• Perforce (non-free)
• 2002: Subversion
• 2003:
• arch
• ArX
• Darcs
• So6
• 2004:
• Bazaar
• Codeville
• 2005:
• git & cogito
• Mercurial
• monotone
• Bazaar-NG

• So many! Why? Can't we all just work together?