1. CSC255-702/703 - CTI/DePaul CSC 255 Information Structures and Representation Fall 2002 Instructor: Dr. Ufuk Verun E-Mail: UVerun@cs.depaul.eduUVerun@cs.depaul.edu Office: CTI CS&T 702 Phone ext: 2822

2. CSC255-702/703 - CTI/DePaul2 Course Resources Textbook: Computer Science - An Overview (7 th Edition), J. Glenn Brookshear Addison-Wesley ISBN 0-201-78130-1 www.aw.com/brookshear Instructor Web Site: www.depaul.edu/~uverun Computer Science an overview EDITION 7 J. Glenn Brookshear

3. CSC255-702/703 - CTI/DePaul3 CSC 255 Lecture 1 Origin and Evolution of Computer Science (Chapter 0 - Introduction from Brookshear) Modified by Ufuk Verun from Jim Janossy © 2002 Jim Janossy, DePaul University CTI - Chicago

4. CSC255-702/703 - CTI/DePaul4 Resources This PowerPoint presentation is available for download at www.depaul.edu/~uverun/classes/CSC255/fal l2002/slides/Lecture_01.ppt www.depaul.edu/~uverun/classes/CSC255/fal l2002/slides/Lecture_01.ppt Textbook: Chapter 0 Print slides at 6 slides/page, avoid waste! Exams are based on slide content, homework and assigned readings

5. CSC255-702/703 - CTI/DePaul5 Scope of CSC 255 Before you can add to a science, you need to understand the basics of what has already been developed: Basic information storage in digital form Algorithm evolution and representation Basic data structures

6. CSC255-702/703 - CTI/DePaul6 Computer Science is More than “Point-and-Click” “We cannot become knowledgeable in Computer Science by studying only a few topics as isolated subjects or merely by learning how to use the computing tools of today.“

7. CSC255-702/703 - CTI/DePaul7 “Point-and-Click” = GUI GUI = “Graphical User Interface” Human / computer interface is how people interact with computers Windows is a GUI CTI’s Human/Computer Interface (HCI) major deals heavily with this

8. CSC255-702/703 - CTI/DePaul8 Computer Science Basics… It’s not enough to just learn how to use Windows or browse the web (that’s all fun, but that’s not Computer Science!) Computer Science involves all the work needed to make things happen with a computer: developing algorithms, and how to make machines perform them.

9. CSC255-702/703 - CTI/DePaul9 Definitions A set of steps that defines how a task is performed is an algorithm A machine-compatible representation of an algorithm is called a program Programs are software Machinery is hardware

10. CSC255-702/703 - CTI/DePaul10 Algorithm = Recipe! “Once an algorithm for performing a task has been found, the performance of that task no longer requires an understanding of the principles on which the algorithm is based. Instead, the performance of the task is reduced to merely following directions.”

11. CSC255-702/703 - CTI/DePaul11 Algorithm Representations Programming languages communicate algorithms to a computing machine Languages are based on paradigms (how the universe is viewed) Systems are made of many programs

12. CSC255-702/703 - CTI/DePaul12 Bit = Binary Digit The basic digital resource Only two states (on/off, high/low, 1/0) Electronic / magnetic / optical mediums How is information mapped to bits? What kind of information? Text, quantities, pictures, …

13. CSC255-702/703 - CTI/DePaul13 Basic Kinds of Information Text - characters like “Hello there” Quantities - numbers that can be involved in computations: Integers (whole numbers) like 123 Numbers with fractional parts like 56.78 Images - pictures, still or moving Sounds - digitized audio

14. CSC255-702/703 - CTI/DePaul14 Why Digital Storage? Easier, less expensive to capture Readily stored using magnetic or optical media, and easily transmitted Fast to search, and combine with others Very readily manipulated: updated, added to, modified Digital circuitry is mass produced and inexpensive, more resistant to errors

15. CSC255-702/703 - CTI/DePaul15 Data Storage Bits........ = Bytes Columns (“fields”) Rows (“records”) Tables (“files”)

16. CSC255-702/703 - CTI/DePaul16 Computing Machines of 1600’s Pascal (1623-1662) Gottfrield Wilhelm Leibneiz (1646-1716) Simple adding calculators Gears and mechanical devices “Output” read from wheels with numbers Very slow

17. CSC255-702/703 - CTI/DePaul17 Computing Machines of 1800’s Charles Babbage (1792-1871) Joseph Jacquard (1752-1834) Herman Hollerith (1860-1929) Programs and/or data on cards Mechanical or electrical Still slow

18. CSC255-702/703 - CTI/DePaul18 Computing Machines of 1900’s Atanasoff / Berry, Iowa State, (1938) George Stibitz, Bell Labs, (1940) Howard Aiken, Harvard Mark I (1944) Eckert / Mauchly, ENIAC, 1946, first commercial computer, UNIVAC, 1950 Parts adapted from radio technology Thousands of calculations per second

19. CSC255-702/703 - CTI/DePaul19 Progression of Electronic Technology for Computing 1940-50’s: vacuum tubes 1960’s: individual transistors 1970’s: integrated circuits 1980’s and 90’s: denser and denser integrated circuits 2000+: millions of transistors on a chip, whole CPU on a chip

20. CSC255-702/703 - CTI/DePaul20 Early Days of Computers

21. CSC255-702/703 - CTI/DePaul21 Babbage’s Difference Engine - Circa 1834

22. CSC255-702/703 - CTI/DePaul22 Vacuum Tubes of 1940’s…

23. CSC255-702/703 - CTI/DePaul23 ENIAC - 1946

24. CSC255-702/703 - CTI/DePaul24 ENIAC - 1946

25. CSC255-702/703 - CTI/DePaul25 ENIAC Programming

26. CSC255-702/703 - CTI/DePaul26 ¼ inch ENIAC on a Chip - 1997

27. CSC255-702/703 - CTI/DePaul27 Abstraction See a pattern Eliminate trivial details (generalize) Solution becomes a new component Encapsulate the solution Whole components can interact Construct higher-level solutions as combinations of components

28. CSC255-702/703 - CTI/DePaul28 Ethical Concerns Computers “amplify” the scope and impact of actions Privacy - not just snooping, but amassing of data otherwise not connected Malicious hacking/intrusion via internet Software ownership and copyright