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“Free software”

• Remember...• In the beginning, all software was free

- Just a means to sell hardware

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Public Domain• Something that is not copyrighted

- Anyone can use or modify it without restrictions

• Most early software was in this category

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Public Domain• Very popular in minicomputer /

microcomputer era- BASIC

• Examples

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Potential Problem

• Public domain software can be- modified- resold as commercial software

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Potential Problem

• Public domain software can be- modified- resold as commercial software

• Example:- UNIX

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Potential Problem

• Public domain software can be- modified- resold as commercial software

• Example:- UNIX- BASIC

(depends on your point of view)

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Richard Stallman

• Programmer at MIT’s AI lab (1970s)• Disillusioned by increasing commercialism

in software

http://vududevil.wordpress.com/2007/11/06/richard-stallman-llena-teatro-en-tijuana-bc/

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Richard Stallman

• Founds GNU project (1983)- “Gnu’s Not Unix”

• Goal:- Create a “free” implementation of Unix

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Free?

• As in “free pizza”?- No.

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Free?

• As in “free pizza”?- No.

• As in “freedom”?- It depends on who you ask.

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Free?

• As in “whatever Richard Stallman’s definition of freedom is?”

- Yes!

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GPL

• GNU General Public License• In a nutshell:

- You must have access to source code- You can modify the software at will- If you distribute it, you must

provide access to source code grant same rights to modify & distribute

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Gradual success...

• Text editor: Emacs• Compiler: GCC• Parser generator: Bison• Other utilities slowly coalesce

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Gradual success...

• Almost a completely functioning OS (1990)• Missing one piece...

- The “kernel”

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Meanwhile....

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Linus Torvalds

• 1991• 22-year-old student at University of

Helsinki (Finland)• Wrote a terminal emulator for MINIX

http://www.linuxtoday.com/special/lwce2/big_linus_keynote.jpg

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Linux

• Terminal emulator project evolves into an operating system

- Version 0.01- 17 September 1991

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Linux

• Original name: “Freax”• A friend suggested “Linux” instead

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Copyright

• Original copyright said Linux could not be sold

- Problematic• So, Linus switched to GPL for version 0.12

- Why?

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And now...

• Suddenly- GNU project had a kernel!- A complete Unix-compatible system without

Unix.

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And now...

• Suddenly- GNU project had a kernel!- A complete Unix-compatible system without

Unix.- (well, almost.)

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Progress

• Version 0.12 supports X Window System (1992)

• Next version: 0.95 (1992)• Version 1.0 (1994)

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Idealogy clashes

• Linus Torvalds vs Andrew Tanenbaum

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Idealogy clashes

• Linus Torvalds vs Andrew Tanenbaum• Richard Stallman vs the world

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Idealogy clashes

• Linus Torvalds vs Andrew Tanenbaum• Richard Stallman vs everybody• “Open source” vs “Free software”

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Reminder

• Presentation sign-ups

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“Test Question”

• On a scrap of paper, write a question that encapsulates one of the points from today's class, and turn it in.

• (Put your name on it!)