1. Intelligent Data Systems Laboratory Foundations of Computing Special Lecture for 컴퓨터개념및실습 2016. 5. 9.

2. IDS Lab. 2016 2016 AlphaGo vs Lee Sedol

3. IDS Lab. !! Tipping Points 1.Digitizing Information 2.Stored-Program Computers 3.Transistor / IC / Communication Tech 4.PC 5.Internet 6.World Wide Web 7.Layered SW Dev. Majority of material taken from L. Snyder, Fluency with Information Technology, 6 th Ed., Pearson, 2015.

4. IDS Lab. 1. Digitizing Information  Data represented as numbers Getting a machine to read digital information Census data digitized (1890) Herman Hollerith invented a punch card reader in 1890 Punch cards digitized the process (not a computer, a card reader) In 1880 it took 8 years to process the data by hand in US Census Bureau The punch card reader shortened the process in 1 year

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6. 2. Stored-Program Computers (1946)  Von Neumann Computer Architecture Programs (instructions) stored in memory Programs can be changed quickly, more complex, and autonomous  Central processing unit (CPU) processes the instructions  ENIAC: started in 1943 finished in 1946 University of Pennsylvania 30 tons, 17,000 vacuum tubes

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8. 3. Transistors / ICs / Communications  Transistors (1956) by 3 bell labs scientists John Bardeen, Walter Brattain, William Shockley Overcome the problems of vacuum tubes Low power, less heat Extremely reliable Small in size and weight The problem: lots of assembly required

9. IDS Lab. 3. Transistors / ICs / Communications  Integrated Circuits (IC) (1958) Transistors and connective parts (e.g., wires) are fabricated together in a multistep process, called integration Photolithography makes it all possible by “printing” the wires onto the circuits IC 집적회로 : 1958 Micro processor (VLSI): 1971

10. IDS Lab. 3. Transistors / ICs / Communications  Communications

11. IDS Lab. 4. Personal Computers (PC) (1973) 1973: first personal machine Xerox’s Alto, $40,000 in 1973  Famous CEO said “There is no reason for any individual to have a computer in their home.” How many computers do you have with you today?

12. IDS Lab. 5. Internet The Internet (1969) – A network of networks – ARPANet sent its first packet in 1969 (used for email and file transfer) A B C ?

13. IDS Lab. TCP/IP TCP/IP Postcard Analogy – The Internet is like sending a novel to your publisher using postcards – The novel is broken into small units that fit on a numbered postcard – As each postcard is completed, it is mailed – Sooner or later, your publisher received the postcards, but not necessarily in sequential order, nor do they take the same route – The numbered postcards are finally arranged in order – These “postcards” are really IP packets IP Packets hold: one unit of information, the destination IP, and their sequence number (which packet they are)

14. IDS Lab. Computer Addresses IP Address – a unique address given to each computer connected to the Internet –a series of four numbers (one byte each) separated by dots Domain Name arts.snu.ac.kr www.snu.ac.kr mail.mycompany.com Domain Name Server (DNS) Domain Name  IP Address

15. IDS Lab. 6. WWW World Wide Web (1993) – HTTP: universal protocol for requesting and sending info – HTML: a standard formatting convention for web documents – Mosaic: first widely used Web browser

16. IDS Lab. Requesting a Web Page Client and server setting Web browsers and Web servers both “speak” HTTP The file can be identified by its URL (Universal Resource Locator) http://www.cs.snu.ac.edu/homes/snyder/index.html The URL has 3 main parts: Protocol, Server computer’s name, Page’s pathname

17. IDS Lab. Requesting a Web Page ① Type in URL ② … ③ Establish a TCP conection with the server

18. IDS Lab. Describing a Web Page Servers do not store Web pages in the form seen on our screens The pages are stored as a description of how they should appear on the screen (in HTML form) The browser receives the description/source file in HTML form and creates the Web page image that is described There are 2 advantages to storing and sending the source rather than the image itself: – A description file usually requires less information – The browser can adapt the source image to your computer more easily

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20. 7. Layered Software Development Until 1980, programs had little structure, and were hard to understand – Programs at one level apply code for lower levels, and provide more advanced facilities for higher levels – Concept of Module – Concept of Information Hiding  API – Concept of Reuse – Concept of Object-Oriented Programming: C++, Java

21. Basic Computer Architecture

22. IDS Lab. Anatomy of a Computer All computers, regardless of their implementing technology, have five basic parts or subsystems: – Memory – Control unit – Arithmetic/logic unit (ALU) – Input unit – Output unit

23. IDS Lab. Instruction Execution Engine The Fetch/Execute Cycle  Get the next instruction  Figure out what to do  Gathering the data needed to do it  Do it  Save the result These operations are repeated in a never-ending sequence (billions / sec)!

24. IDS Lab. Instruction Fetch (IF)

25. IDS Lab. Instruction Decode (ID)

26. IDS Lab. Data Fetch (DF)

27. IDS Lab. Instruction Execution (EX)

28. IDS Lab. Return Result (RR) Step