Intro
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This document provides an introduction and overview of the COMP3231/9201/3891/9283 Operating Systems course at UNSW. It discusses the course coordinators, prerequisites, lectures, tutorials, assignments, assessment breakdown, textbooks and references. The course aims to educate students in basic OS concepts, hardware characteristics relevant to OS, and tradeoffs faced by OS in supporting applications efficiently. Topics covered include processes, concurrency, memory management, file systems, I/O, scheduling, and possibly security.
Intro
- 1. Introduction COMP3231/9201/3891/9283 (Extended) Operating Systems Dr. Kevin Elphinstone Dr. Leonid Ryzhyk
- 2. Operating Systems @ UNSW
- 3. John Lions (19 January 1937 – 5 December 1998) • Played a leading role in bringing UNIX to Australia – Founding president of Australia UNIX Users Group • Based his OS course on understanding the UNIX V6 source code – Forward thinking at the time. – Authored a source code commentary to aid understanding “After 20 years, this is still the best exposition of the workings of a "real" operating system” — Ken Thompson, co-author of Unix – Publication was suppressed by AT&T, and the commentary was widely photocopied "underground". – Finally officially published in 1996. • Lions Garden dedicated in 2002 • 2006 Alumni established John Lions Chair of Operating Systems – 2009 Gernot Heiser became the inaugural chair.
- 4. 1990s • 1991 DiSy (Distributed Systems) group started – Gernot Heiser (and others) and two PhD students: Jerry Vochteloo and myself. • 1995 Established collaboration with Jochen Liedtke, original architect of L4 microkernel – Developed L4mips microkernel • Featured fastest interprocess communication at the time • Still fastest on single issue processor U4600 • 1997 COMP9242 Advanced Operating Systems was born. – Designed and built U4600: • 64-bit MIPS computer – Software based on L4mips
- 5. 2000s • 2002 UNSW/ANU wins bin to establish NICTA • Two parallel streams began – Commercialisation of L4 – ERTOS research group and agenda established; Gernot Heiser leader.
- 6. UNSW/NICTA startup OK Labs Timeline > 1994: Begin of microkernel research at UNSW > 1997–2003: multiple open-source releases > 2004: First consulting engagement with Qualcomm > 2006: Open Kernel Labs founded, first L4 phone ships in Japan > Today: Customer base of blue-chip multinationals • Qualcomm, ST-Ericsson, Motorola, … > Total deployment to date 1.1 billion devices! • Present shipping rate: > 20 million per month 6
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- 9. Welcome to OS @ UNSW 9
- 10. Course Outline • Prerequisites – COMPXXXX Data structures and algorithms • Stacks, queues, hash tables, lists, trees, heaps,…. – COMPXXXX Microprocessor and Interfacing • Assembly programming • Mapping of high-level procedural language to assembly language • Interrupts – You are expected to be competent programmers!!!! • We will be using the C programming language – The dominant language for OS implementation. – Need to understand pointers, pointer arithmetic, explicit memory allocation. 10
- 11. Why does this fail? void set(int *x, int *y) { *x = 1; *y = 2; } void thingy() { int *a, *b; set(a,b); printf(“%d %dn”,*a,*b); } 11
- 12. Lectures • Common for all courses (3231/3891/9201/9283) • Tue, 3-5pm, Biomedical Theatre D (K-E27-D) • Thu, 3-4pm, Chemical Sc M18 • (ex Applied Sc (K-F10-M18) Webster Theatre B – Extended OS Thu 4-5pm, Webster 251 (K-G14-251) • starts in week 2 – The lecture notes will be available on the course web site • Available prior to lectures, when possible. • Slide numbers for note taking, when not. – The lecture notes and textbook are NOT a substitute for attending lectures. 12
- 13. Extended OS Comp3891/9283 • A combination of: – Examination of topics in more depth – Looking at research in area (past/present) – OS/161 internals in more depth • Assumes the tutorials are too easy – Effectively replaces the tutorial with extra interactive lecture. 13
- 14. Tutorials • Start in week 2 • A tutorial participation mark will contribute to your final assessment. – Participation means participation, NOT attendance. – Comp3891/9283 students excluded – Comp9201 optional • You will only get participation marks in your enrolled tutorial. 14
- 15. Assignments • Assignments form a substantial component of your assessment. • They are challenging!!!! – Because operating systems are challenging • We will be using OS/161, – an educational operating system – developed by the Systems Group At Harvard – It contains roughly 20,000 lines of code and comments 15
- 16. Assignments • Don’t under estimate the time needed to do the assignments. – 80% is understanding – 20% programming • If you start a couple days before they are due, you will be late. • To encourage you to start early, – Bonus 10% of awarded mark of the assignment for finishing a week early – See course handout for exact details • Read the fine print!!!! 16
- 17. Assignments • Assignments are in pairs – except warm-up Asst0 – Info on how to pair up available soon • We usually offer advanced versions of the assignments – Available bonus marks are small compared to amount of effort required. – Student should do it for the challenge, not the marks. – Attempting the advanced component is not a valid excuse for failure to complete the normal component of the assignment • consider it a different optional assignment • Extended OS students (COMP3891/9283) are encouraged to attempt the advanced assignments 17
- 18. Assignments • Three assignments – due roughly week 6, 9, 13 • Also warm up bonus assignment due in week 4 – It’s a warm up to have you familiarize yourself with the environment and easy marks. – Do not use it as a gauge for judging the difficulty of the following assignments. 18
- 19. Assignments • Late penalty – 4% of total assignment value per day • Assignment is worth 20% • You get 18, and are 2 days late • Final mark = 18 – (20*0.04*2) = 16 (16.4) • Assignments are only accepted up to one week late. 8+ days = 0 19
- 20. Assignments • To help you with the assignments – We dedicate a tutorial per-assignment to discuss issues related to the assignment – Prepare for them!!!!! 20
- 21. Plagiarism • We take cheating seriously!!! • We systematically check for plagiarised code – Penalties are generally sufficient to make it difficult to pass 21
- 22. Sample Cheating Statistics Session 1998/S1 1999/S1 2000/S1 2001/S1 2001/S2 2002/S1 2002/S2 2003/S1 2003/S2 enrolment 178 410 320 300 107 298 156 333 133 suspected cheaters 10(6%) 26(6%) 22(7%) 26(9%) 20(19%) 15(5%) ???(?%) 13 (4%) ???(?%) full penalties * * * * 2 6 9 14 10 9 5 2 1 reduced penalties 7 15 7 7 5 4 2 2 9 cheaters failed 4 10 16 16 10 12 5 4 ? cheaters suspended 0 0 1 0 0 1 0 0 0 *Note: Full penalty 0 FL not applied prior to 2001/S1 22
- 23. Exams • There is NO mid-session • The final written exam is 2 hours • Supplementary exams are oral. – Supplementaries are available according to UNSW & school policy, not as a second chance. 23
- 24. Assessment • Exam Mark • Class Mark Component Component – Max mark of 100 – Max mark of 100 • Based solely on the • 10% tutorial final exam participation • 90% Assignments 24
- 25. 3891/9283 • No tutorial participation component • Assignment marks scaled to 100 25
- 26. 9201 • Optional tutorial participation, we’ll award the better mark of – Tutorial participation included as for comp3231 – Class marked based solely on the assignments 26
- 27. Undergrad Assessment • The final assessment is the harmonic mean of the exam and class component. • If E >= 40, 2 EC M= E +C 27
- 28. Postgrads (9201/9283) • Maximum of a 50/50 weighted harmonic mean and a 20/80 harmonic mean – Can weight final mark heavily on exam if you can’t commit the time to the assignments – You are rewarded for seriously attempting the assignments • if E >= 40, 2E C 5E C M = max( E + C ; E + 4C ) 28
- 29. Assessment • If E < 40 2 EC M = min 44, E +C 29
- 30. Final M ark = 50 100 90 80 Exam Mark Required to Pass 70 60 Harm 50/50 50 Harm 20/80 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 Class Mark 30
- 31. Assessment • You need to perform reasonably consistently in both exam and class components. • Harmonic mean only has significant effect with significant variation. • Reserve the right to scale, and scale courses individually if required. – Warning: We have not scaled in the past. 31
- 32. Textbook • Andrew Tanenbaum, Modern Operating Systems, 3rd Edition, Prentice Hall 32
- 33. References • A. Silberschatz and P.B. Galvin, Operating System Concepts, 5th, 6th, or 7th edition, Addison Wesley • William Stallings, Operating Systems: Internals and Design Principles, 4th or 5th edition, Prentice Hall. • A. Tannenbaum, A. Woodhull, Operating Systems--Design and Implementation, 2nd edition Prentice Hall • John O'Gorman, Operating Systems, MacMillan, 2000 • Uresh Vahalla, UNIX Internals: The New Frontiers, Prentice Hall, 1996 • McKusick et al., The Design and Implementation of the 4.4 BSD Operating System, Addison Wesley, 1996 33
- 34. Forum and Wiki • Forum for Q/A about assignments and course – Ask questions there for the benefit of everybody – Look there before asking • Wiki – Look here before asking on the forum – Contains • Tips for setting up – Note: we only support CSE machines, you’re on your own at home – Most students get a workable home environment going • Tips for the assignments – Only as good as feedback or your contributions 34
- 35. Consultations/Questions • Questions should be directed to the forum. • Admin related queries to Aaron Carroll aaronc@cse.unsw.edu.au • Personal queries can be directed to me kevine@cse.unsw.edu.au • We reserve the right to ignore email sent directly to us (including tutors) if it should have been directed to the forum. • Consultation Times – TBA 35
- 36. Course Outline • “the course aims to educate students in the basic concepts and components of operating systems, the relevant characteristics of hardware, and the tradeoffs between conflicting objectives faced by operating systems in efficiently supporting a wide range of applications.” 36
- 37. Course Outline • Processes and threads • Concurrency control • Memory Management • File Systems • I/O and Devices • Scheduling • Security (maybe) 37