6. Computer History - MainFrame
http://en.wikipedia.org/wiki/Image:Honeywell-
Bull_DPS_7_Mainframe_BWW_March_1990.jpg (GFDL)
7. Source Code
• Computer Instructions are coded in binary
format 00101...
• A more human friendly method to program
computer:
/* Hello World program */
#include<stdio.h>
main()
{ printf("Hello World"); }
8. Source Code (Cont.)
• Convert source code into binary instructions by
a computer compiler
• Vertical market – one supplier for all computer
needs
• Source code by itself own had no commercial
value -> freely distributed
11. Changes in Computer Industry
• Personal computers - hardware and software
could be sold separately
• Money could be made by closing up source
code
• Some programmers sold the copyright of the
source code of collaborative projects and stole
of work of others
• AT&T Unix incident
13. Responses to the Theft
• Release source code that could not be used
commercially
• Release source code that must remain freely
available -> Software Freedom
• 1983 GNU project, Unix Clone
• 1985 Free Software Foundation, Free as in
Free Speech, General Public License (GPL)
14. Free/Open Source Software
20+ Years Down the Road
• Linux
IDC's Worldwide Quarterly Server Track
–2008 2Q $13.9 billion total
–Microsoft $5.1 billion 36.5% Growth -1.7%
–Linux $1.9 billion 13.4% Growth 9.4%
(http://practical-tech.com/infrastructure/linux-server-share-
keeps-growing/)
15. Free/Open Source Software
20+ Years Down the Road
• Apache
–Most popular web server
–Always more popular than IIS
(http://www.netcraft.com/)
• Foundation of Web 2.0
–Facebook: Apache PHP
–Twitter: Ruby on Rails