1. Operating Systems Vivek Pai Lecture 1 Sep 12, 2002

2. COS 318 - Operating Systems, Vivek Pai2 Introduction Who I am  Vivek Pai  PhD 99/00, Rice  Research: OS, networking, high- performance apps Why I do this  Fun  Interesting  Design opportunities  “Profitable”

3. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai3 About this course… Principles  OS design  Some theory  Rationale  Practice Not trade school Goals  Understand OS decisions  Basis for future learning  Get hands dirty Not “elite hacker”

4. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai4 Expect (Some) Pain Fast pace Lots of projects (programming) Hard material Course changing based on feedback Not the end of the world – course favorably received last year, under much more trying circumstances

5. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai5 What Works & Doesn’t Works  Solid C background  Flexible approach  Grasping Prereqs  Open mind  Einstein  Feedback sheets Doesn’t  Schedule overload  Missing background  Mathematical precision

6. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai6 Why So Many Grades?  Programming projects  Midterm & final exams  Quizzes ( see me about health/school absences ) Intended to reduce pressure/anxiety More data points = less noise Somewhat generous extra credit

7. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai7 Some Relief Grades based on mean/deviation People have done generally well in the past 25 / 38 As 17 / 11 Bs 4 / 7 Cs Honor System  Use common sense  Ask for clarification  Cooperation OK  Work is your own (pairs for labs)

8. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai8 There Is No Magic This Is Engineering  Tradeoffs  Constraints  Optimizations  Imperfection Nothing’s Permanent  High rate of change  Lots of inertia  Cost/benefit analyses  Human error

9. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai9 Mechanics – Info  My home page  Course home page  Newsgroup  Precepts  Design reviews

10. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai10 Mechanics – Grading  Assigned readings  20% quizzes  20% midterm  20% final  40% projects – some extra credit  Late policy: 6 hours: 91% 12 hours: 84% 24 hours: 71% 48 hours: 50%

11. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai11 Mechanics - People  See web site – it’s up to date!  Basically –Me – quizzes, exams –TAs – precepts, labs –Office hours – T, W, Th or by Appt

12. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai12 Mechanics – Readings Modern Operating Systems Tannenbaum Different from last time Available at Ustore Various readings – will be available from my home page (course web site)

13. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai13 Mechanics - Projects  6 projects, 2 themes –Build parts of a mini-OS –Write applications that interact with OS  2 weeks each  Uses Linux, sort of  Partners – be decent to each other Option – one big project – only for the brave

14. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai14 Send Me Your Details  Name  Year  Major  E-mail address  Phone #  Picture via URL  Why you’re taking the class  What you’d like/hope to learn

15. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai15 What Is an OS?

16. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai16 What Is an OS? “Code” that:  Sits between programs & hardware  Sits between different programs  Sits betweens different users But what does it do?

17. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai17 What Is an OS? Resources  Allocation  Protection  Reclamation  Virtualization Services  Abstraction  Simplification  Convenience  Standardization Makes computers simpler

18. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai18 What Is an OS? Resources  Allocation  Protection  Reclamation  Virtualization Finite resources Competing demands Examples:  CPU  Memory  Disk  Network

19. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai19 What Is an OS? Resources  Allocation  Protection  Reclamation  Virtualization You can’t hurt me I can’t hurt you Implies some degree of safety & security

20. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai20 What Is an OS? Resources  Allocation  Protection  Reclamation  Virtualization The OS giveth The OS taketh away Voluntary at run time Implied at termination Involuntary Cooperative

21. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai21 What Is an OS? Resources  Allocation  Protection  Reclamation  Virtualization Illusion of infinite, private resources Memory versus disk Timeshared CPU More extreme cases possible (& exist)

22. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai22 Mechanism & Policy Mechanism – tool to achieve some effect Policy – decisions on how to use tool Examples:  All users treated equally  All program instances treated equally  Preferred users treated better  No deterministic behavior at all

23. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai23 Is There a Perfect OS?

24. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai24 Is Any OS Complete? Portability Security Fairness Robustness Efficiency Interfaces

25. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai25 History Lessons 60’s-70’s - Mainframes  Rise of IBM 70’s - 80’s – Minicomputers  Rise of Digital Equipment 80’s - 90’s – PCs  Rise of Intel, Microsoft Now – Post-PC  Distributed applications

26. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai26 Historical Comparison MainframeMiniMicro System $/ worker 10:1 – 100:1 10:1 – 1:1 1:10-1:100 GoalSystem utilization Overall cost Productivity TargetCapacityFeaturesEase of Use

27. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai27 Constant Employment?  New hardware  New features  New approaches Examples: Palm, Java, WWW

28. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai28 May You Live in Interesting Times…  Processors double in 18 months  Disk doubling every 12 months  Global bandwidth every 6 months  “Sweet spot” constantly decaying Do people ever double?

29. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai29 Send To vivek@cs…  Name  Year  Major  E-mail address  Phone #  Picture via URL  Why you’re taking the class  What you’d like/hope to learn Consider this a grade

30. Sep 12, 2002COS 318 - Operating Systems, Vivek Pai30 And Now For Something Completely Different…