1991..

• On 26 August 1991, Linus Torvalds posted to comp.os.minix news group:

      I'm doing a (free) operating system (just a hobby, won't be
      big and professional like gnu) for 386(486) AT clones. This
      has been brewing since April, and is starting to get ready.

      . . .

      It is NOT portable (uses 386 task switching etc), and it
      probably never will support anything other than AT-harddisks,
      as that's all I have :-(.

• After Linus's announcement, many people contributed code to the project
• By September 1991, Linux version 0.01 was released with ~10,000 lines of code
• December 1991 Linux 0.11 was self-hosted - it could be compiled by a computer running Linux 0.11
• First GPL'd version (0.12) in February 1992
• X Window System ported to Linux in March 1992 (Linux 0.95)
• March 1994 -> Linux 1.0.0 (~176,000 lines of code)
• January 1999 -> Linux 2.2.0 (~1,8 million lines of code)
• June 2009 -> Linux 2.6.30 (~11,6 million lines of code)
• While not originally designed to be portable, Linux is now one of the most widely ported operating system kernels
• The cost to redevelop the Linux kernel version 2.6.0 in a traditional proprietary development setting has been estimated to be 467 million euro in 2004 prices using the COCOMO man-month estimation model
• In 2006, a study funded by the European Union put the redevelopment cost of kernel version 2.6.8 higher, at 882 million euro
• As early as on January 1992, it was said that Linux is obsolete