1. IntroductionCS-4513, D-Term 20071 Distributed Computing Systems Hugh C. Lauer Adjunct Professor (Slides include materials from Operating System Concepts, 7 th ed., by Silbershatz, Galvin, & Gagne and from Modern Operating Systems, 2 nd ed., by Tanenbaum)

2. IntroductionCS-4513, D-Term 20072 Outline for Today Introduction to CS-4513 What is “Distributed Computing” –An example of a distributed computation Networks Assignment of Project #1

3. IntroductionCS-4513, D-Term 20073 Introduction to CS-4513 Continues CS-3013, Operating Systems –File Systems One lecture in C-Term CS-3013 No coverage in A-Term CS-3013 Networks & Communication Computations that run on more than one machine Close together Far apart Internet and World Wide Web

4. IntroductionCS-4513, D-Term 20074 Textbook and Web Textbooks:– You should own or have access to one of the following from CS-3013 –Operating Systems Concepts, 7 th ed, by Silberschatz, Galvin, and Gagne, John Wiley and Sons, 2005 –Modern Operating Systems, 2 nd edition, by Andrew S. Tanenbaum, Prentice Hall, 2001 Supplemental Text:– –Distributed Systems: Principles and Paradigms, Tanenbaum and Van Steen, Prentice-Hall, 2007 Course Information: –http://www.cs.wpi.edu/~cs4513/d07/http://www.cs.wpi.edu/~cs4513/d07/

5. IntroductionCS-4513, D-Term 20075 Prerequisites Prerequisites: –CS-3013, Operating Systems or equivalent –C and C++ programming, esp. low level programming –Data structures –Unix/Linux user experience and access –Computer Organization 1 st reading assignment: any of the following –Silbershatz, §16.1-16.4 –Tanenbaum, §8.3 –Tanenbaum & Van Steen, Chapter 1

6. IntroductionCS-4513, D-Term 20076 Schedule & Logistics Schedule –Goddard Hall 227 –9:00 – 10:50 AM –Tuesdays and Fridays thru May 1 –No class on April 17 –14 classes total Exams –Mid-term on April 3 –Final on May 1 Unannounced Quizzes –May occur at any time –May be at beginning, middle, or end of class Mobile Phones, pagers, laptops, and other devices OFF during class ~4 Programming Projects –Fossil Lab Office Hours –Adjunct Office, Fuller 239 –by appointment, or –Normally ½ hour before and after class Teaching Assistant –Choong-Soo Lee clee01 **at** cs.wpi.edu Contact – @ cs.wpi.edu –Adjunct office phone: (508) 831-6470 (shared, no messages)

7. IntroductionCS-4513, D-Term 20077 Grading –Exams – 35% –Programming Projects (~4) – 35% –Class participation, homework, & quizzes – 30% Unless otherwise noted, assignments are to be completed individually, not groups Late Policy – 10%/day –But contact Professor for extenuating circumstances WPI Academic Honesty policy

8. IntroductionCS-4513, D-Term 20078 Miscellaneous Is this course the capstone for a Minor in CS? Anyone needing a project for BS & MS credit?

9. IntroductionCS-4513, D-Term 20079 Ground Rule There are no “stupid” questions. It is a waste of your time and the class’s time to proceed when you don’t understand the basic terms. If you don’t understand it, someone else probably doesn’t, either.

10. IntroductionCS-4513, D-Term 200710 Introductions Who are you? –Name, year, degree, major –Work experience in computing, etc.? C & C++ experience –Other programming experience Why CS-4513 – Distributed Computing Systems? Anything else relevant?

11. IntroductionCS-4513, D-Term 200711 Instructor — Hugh C. Lauer Adjunct Professor Ph. D. Carnegie-Mellon 1972-73 –Dissertation “Correctness in Operating Systems” Lecturer: University of Newcastle upon Tyne, UK 30+ years in research and development in industry in USA Research and system topics –Operating Systems –Proofs of Correctness –Computer Architecture –Networks and Distributed Computing –Real-time networking –3D Volume Rendering –Surgical Simulation and Navigation –…

12. IntroductionCS-4513, D-Term 200712 Systems Experience University of Newcastle Systems Development Corporation Xerox Corporation (Palo Alto) Software Arts, Inc. Apollo Computer Eastman Kodak Company Mitsubishi Electric Research Labs (MERL) Real-Time Visualization Founded and spun out from MERL Acquired by TeraRecon, Inc. SensAble Technologies, Inc. Currently: CTO, Dimensions Imaging, Inc.

13. IntroductionCS-4513, D-Term 200713 Accomplishments 21 US Patents Two seminal contributions to CS –Duality Hypothesis of Operating System Structures (with Roger Needham) –First realization of opaque types in type-safe programming languages (with Ed Satterthwaite) VolumePro™ –World’s first 2D, 3D, and 4D volume rendering system at interactive speeds for medical, seismic, and scientific visualization

14. IntroductionCS-4513, D-Term 200714 VolumePro™ Interactive volume rendering of 3D data such as MRI scans CT scans Seismic scans Two generations of ASICs, boards, software VolumePro 500 – 1999 VolumePro 1000 – 2001 CTO, Chief Architect of VolumePro 1000 7.5-million gate, high-performance ASIC 10 9 Phong-illuminated samples per second

15. IntroductionCS-4513, D-Term 200715 Sample images from VolumePro

16. IntroductionCS-4513, D-Term 200716 Class Discussion What is Distributed Computing?

17. IntroductionCS-4513, D-Term 200717 Distributed System Collection of computers that are connected together and (sometimes) interact Many independent problems at same time Similar Different Or … –One very big problem (or a small number) Computations that are physically separated Client-server Inherently dispersed computations

18. IntroductionCS-4513, D-Term 200718 Distributed Computing Spectrum Many independent problems at same time Similar — e.g., banking & credit card; airline reservations Different — e.g., university computer center; your own PC Or … –One very big problem (or a few) Computations that are physically separated Client-server Inherently dispersed computations

19. IntroductionCS-4513, D-Term 200719 Multiprocessing  Distributed Computing (a spectrum) Many independent problems at same time Similar — e.g., banking & credit card; airline reservations Different — e.g., university computer center; your own PC Or … –One very big problem (too big for one computer) Weather modeling, finite element analysis; drug discovery; gene modeling; weapons simulation; etc. Computations that are physically separated Client-server Inherently dispersed computations

20. IntroductionCS-4513, D-Term 200720 Multiprocessing  Distributed Computing (a spectrum) Many independent problems at same time Similar — e.g., banking & credit card; airline reservations Different — e.g., university computer center; your own PC Or… –One very big problem (too big for one computer) Weather modeling, Finite element analysis; Drug discovery; Gene modeling; Weapons simulation; etc. Computations that are physically separated Client-server Dispersed – routing tables for internet; electric power distribution.

21. IntroductionCS-4513, D-Term 200721 Observation Same spectrum applies to multiprocessor systems –Much more tightly coupled that traditional “distributed systems” Some differences –“Multiprocessor systems” Usually under same management Very fast communication –“Distributed systems” Sometimes not under same management Slower communication

22. IntroductionCS-4513, D-Term 200722 Another Observation (attributed to R. Hamming) When you change the operating point of a system by an order of magnitude … … you introduce qualitative changes in how to approach problems

23. IntroductionCS-4513, D-Term 200723 Let’s look at an example An inherently distributed computation –I.e., parts of the computation must occur at physically separate locations –Under separate administrations Internet routing tables

24. IntroductionCS-4513, D-Term 200724 The Internet A vast collection of independent computers –~ 600  10 6 All connected together Any computer can send a message to any other Messages broken up into little packets Question: how do packets find their way to destinations?

25. IntroductionCS-4513, D-Term 200725 Internet

26. IntroductionCS-4513, D-Term 200726 Distributed routing algorithm (simplified example) Each node “knows” which networks are directly connected to it. Each node maintains table of distant networks [network #, 1 st hop, distance] Adjacent nodes periodically exchange tables Update algorithm (for each network in table) If (my distance to network > neighbor’s distance to network + my distance to neighbor), then … … update my table entry for that network so that neighbor is first hop.

27. IntroductionCS-4513, D-Term 200727 Distributed routing algorithm (result) All nodes in Internet maintain reasonably up-to-date routing tables Rapid responses to changes in network topology, congestion, failures, etc. Very reliable with no central management!

28. IntroductionCS-4513, D-Term 200728 Characteristic The routing algorithm is inherently distributed Different parts execute in physically separated locations Only nearby nodes “know” whether –Neighbors are up or down –Networks are congested or not

29. IntroductionCS-4513, D-Term 200729 Big networks Network management systems Monitoring health of network (e.g., routing tables) Identifying actual or incipient problems Data and statistics for planning purposes

30. IntroductionCS-4513, D-Term 200730 Next Topic Programming Project Questions?