1. University of Utah 1 Grosch’s Law Herb Grosch (IBM, 1950) A large computer that costs 2X more than a small computer is... -2X faster?

2. University of Utah 2 Grosch’s Law Herb Grosch (IBM, 1950) A large computer that costs 2X more than a small computer is... -2X faster? -4X faster!

3. University of Utah 3 Grosch’s Law Why? -Core memory is cheap -Support circuitry is expensive

4. University of Utah 4 Grosch’s Law Why? -Core memory is cheap -Support circuitry is expensive -No good way to connect machines together

5. University of Utah 5 Grosch’s Law Falters Chip-based memory -Faster, less wiring...

6. University of Utah 6 Grosch’s Law “Repealed” Ethernet! -Finally, a way to link cheap machines together effectively

7. University of Utah 7 Ethernet Yet another Xerox PARC invention (1973) Bob Metcalfe and David Boggs Xerox wanted to network its Alto computers together

8. University of Utah 8 Ethernet Inspirations -Data General “star” network no! -ALOHAnet yes!

9. University of Utah 9 Ethernet Basic idea -Shared coaxial cable connecting all computers -Collision detection -Random backoff

10. University of Utah 10 10 Ethernet Standardization (1979) -DEC, Intel, Xerox agree to use Ethernet -...but not IBM...

11. University of Utah 11 11 Ethernet Becomes common standard for workstation LANs (local area networks) But not for PCs (yet)

12. University of Utah 12 12 Internet Descended from ARPANET A network of many smaller networks -Glued together by TCP/IP

13. University of Utah 13 13 Internet Why? -Technical reasons: ARPA adopts BSD and TCP/IP in 1980 Rise of LANs -Social reasons: ARPA (1970s) National Science Foundation (1980s) InterNIC (1992)

14. University of Utah 14 14 Internet What? -NOT the World Wide Web (yet)

15. University of Utah 15 15 Internet What? -NOT the World Wide Web (yet) -Telnet

16. University of Utah 16 16 Internet What? -NOT the World Wide Web (yet) -Telnet -FTP

17. University of Utah 17 17 Internet What? -NOT the World Wide Web (yet) -Telnet -FTP -Email

18. University of Utah 18 18 Internet What? -NOT the World Wide Web (yet) -Telnet -FTP -Email -BBS

19. University of Utah 19 19 Internet What? -NOT the World Wide Web (yet) -Telnet -FTP -Email -BBS -Usenet (newsgroups)

20. University of Utah 20 20 Internet What? -Gopher (1991) -Menu-based information retrieval system

21. University of Utah 21 21 Gopher Demo

22. University of Utah 22 22 World Wide Web Tim Berners-Lee (1990) CERN -particle physics laboratory between Switzerland and France http://en.wikipedia.org/wiki/Image:Tim_Berners-Lee.jpg

23. University of Utah 23 23 World Wide Web First web browser -“WorldWideWeb” First web server -“httpd” -Implemented on a NeXT computer

24. University of Utah 24 24 World Wide Web http://en.wikipedia.org/wiki/Image:First_Web_Server.jpg

25. University of Utah 25 25 First-ever web page! Want to see it?

26. University of Utah 26 26 Break Time

27. University of Utah 27 27 “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!)