Mac OS Evolution

1978 Apple introduces Apple DOS 3.1, the first operating system for the Apple computers in June.

1984 Apple introduces System 1.

1985 Apple introduces System 2.

1986 Apple introduces System 3.

1987 Apple introduces System 4.

1988 Apple introduces System 6.

1991 Apple introduces System 7 operating system May 13, 1991.

1995 Apple allows other computer companies to clone its computer by announcing its licensed the Macintosh operating system rights to Radius on January 4.

1997 Apple introduces Mac OS 8. 1997Apple buys NeXT Software Inc. for $400 million and acquires Steve Jobs, Apples cofounder, as a consultant.

1999 Apple introduces Mac OS 9.

2001 Apple introduces Mac OS X 10.0 named Cheetah and becomes available March 24, 2001.

2001 Apple introduces Mac OS X 10.1 named Puma and becomes available on September 25, 2001.

2002 Apple introduces Mac OS X 10.2 named Jaguar and becomes available on August 23, 2002.

2003 Apple introduces Mac OS X 10.3 named Panther October 25, 2003.

2004 Apple introduces Mac OS X 10.4 named Tiger at the WWDC on June 28, 2004.

2007 Apple introduces Mac OS X 10.5 named Leopard October 26, 2007.

2008 Apple introduces Mac OS X 10.6 named Snow Leopard and MobileMe at the WWDC on June 9, 2008.

2011 Apple introduces Mac OS X 10.7 named Lion was released on July 20, 2011.

2012 Apple introduces Mac OS X 10.8 named Mountain Lion will be released  in July 2012.