1. Wei University of Connecticut Operating Systems CSE 4300 Lecture 1

2. 2 Information Course web page: Use HuskyCT Link will be on my web page http://www.engr.uconn.edu/~weiwei/ Instructor: Wei Wei weiwei@engr.uconn.edu

3. 3 Today’s Class Course organization & outline Prerequisites & course sign-up Introduction & History of Operating Systems

4. 4 Course Organization Class: junior or senior-level Not for freshman or sophomores Enrollment policy If space becomes an issue, graduating seniors get preference

5. 5 Prerequisites Data Structures & Algorithms Dynamic memory management Lists, Trees Algorithm Analysis Computer Architecture Programming skills: C/C++ Textbook Operating system concepts: Silberschatz, Galvin and Gagne, 7 th Edition

6. 6 Course Grading In-class quizzes: +5% Homework: 20% Programming projects: 30% Exams: exam I 15%, exam II 15%, final 20% Strict late policy – not accepted No incomplete Cheaters will be found and punished Will use sophisticated software to detect plagiarized programs

7. 7 Course Organization Accounts in C27 My office hours and location: Office hours: Tu, Th 3:30pm – 4:30pm Wednesday 1:30pm – 4:30pm Office ITE 331

8. 8 What is a class like? Brief announcements on homework, project, exam Review of previous class lecturing (questions & answers please!) mostly ppt slides (handwriting occasionally) quiz (occasionally) return homework, projects, exam; go over them briefly

9. 9 Introduction to Operating Systems What’s an operating system (OS)? Why learn OS? Historical perspective on operating systems

10. 10 OS: More Traditional View Interface between user and architecture Hides architectural details Implements virtual machine: Easier to program than raw hardware (hopefully) Provides services and coordinates machine activities User-level Applications Operating System Hardware virtual machine interface physical machine interface

11. 11 Operating Systems: Key Features Provides standard services (interface) that hardware implements File system, virtual memory, networking, scheduling, time-sharing… Coordinates multiple applications and users to achieve safety, fairness and efficiency (high throughput) Concurrency, memory protection, networking, security OS design challenges: convenient and efficient Software engineering & systems engineering problems

12. 12 Introduction to Operating Systems What’s an operating system? (OS) Why learn OS? Historical perspective on operating systems

13. 13 Importance of Operating Systems Key component of computer systems Meeting point of software & hardware Understanding how computers work = understanding operating systems OS provides key services required by all application programs Rich topic: OS = most complex software on your PC Windows XP kernel: 40 million lines of code

14. 14 New Developments in OS Design Operating systems: very active field of research Demands on OS’s growing New application spaces (Web, Grid) Rapidly evolving hardware Advent of open-source operating systems – Linux  You can contribute to and develop OS’s!  Excellent research platform

15. 15 Introduction to Operating Systems What’s an operating system? (OS) Why learn OS? Historical perspective on operating systems

16. 16 Generation I (1945-1955) Hardware technology Mechanical relays, then vacuum tubes The Experience No O.S., no library calls Programming in machine language (NOT assembly) Basic I/O E.g. punch cards

17. 17 ENIAC

18. 18 Generation II (1955-1965) Hardware Technology Transistors (smaller, more reliable, affordable) Desktop (really) The Experience Compilers, linkers, loaders are available! Programming done in assembly and FORTRAN I/O: magnetic tape Batch processing

19. 19 Execute multiple “jobs” in batch: Load program Run Print results, dump machine state Repeat Users submit jobs (on cards or tape) Human schedules jobs Operating system loads & runs jobs Batch Processing

20. 20 Examples (Generation II ) IBM 7094: Core memory, disk, subroutine call instruction IBM 701 First machine with an OS

21. 21 Generation III (1965-1980) Hardware technology Integrated Circuits The Experience Multiprogramming Unix is born Examples: IBM 360,370,... DEC PDP-1 to PDP-11, VAX

22. 22 Multiprogramming Allow several programs to run at same time Run one job until I/O Run another job, etc. OS manages interaction between programs: Which jobs to start Protects program’s memory from others Decides which to resume when CPU available

23. 23 The UNIX Era Multics Army of programmers, six years Unix Three (four?) guys, two years Integration of simple tools “Shell”: composable commands Written in C: easily portable

24. 24 Examples (Generation III) PDP-11 IBM 360/30 First general purpose computer

25. 25 Generation IV (1979-1995) MAC (1980’s) Steve Jobs discovers the Graphical User Interface Pioneered at Xerox-PARC Microsoft catches up (1985-1995) GUI on top of MS-DOS. win1.0[85],win2.0[87], win3.x[90], win95, win98 Meanwhile.... MINIX is born (1987) followed by Linux (1992)

26. 26 Examples (Generation IV) The Mac (1984) Windows 3.0 (1990) X-windows

27. 27 Generation V (1990’s-now) Different modalities: Parallel: Multiple processors, one machine Distributed: Multiple networked processors Real-time: Strict or loose deadlines Sensor networks: Many small computers

28. 28 Moral of the Story The only constant: Change In 50 years, almost every computer component now 9 orders of magnitude faster, larger, cheaper Example: 19831999 MIPS0.5500 cost/MIP$100,000$500 memory1 MB1 GB network10 Mbit/s1 GB/s disk1 GB1 Tbyte

29. 29 Moral of the Story, II No counterpart in any other sphere of human existence! Transportation: 200 years to go from horseback (10 mph) to Concorde (1000 mph) = 2 orders of magnitude Communication is closest: 100 years to go from Pony Express (10 mph) to nearly speed of light (600 million mph) = 7 orders of magnitude And operating systems must adapt…

30. 30 Course outline Introduction Process management Multiprogramming, process/thread, CPU scheduling, synchronization, deadlock Memory management segmentation, paging, swapping File system I/O system Advanced topics Protection, Security, etc.