Lecture 1 Advanced Topics in Computer Systems CS262a Prof Brewer Intro Lecture I Administrative Matters Instructors Eric Brewer and Joe Hellerstien Eric Brewer o o o o PhD MIT 1994 Internet Systems Mobile computing Security Parallel computing Founded Inktomi Federal Search Foundation Contact brewer cs berkeley edu Joe Hellerstien o PhD Wisconsin 1995 o Databases declarative networking o Contact hellerstein cs berkeley edu Course prerequisite no entrance exam this year but please review undergrad material Traditional goals of the course o Introduce a variety of current OS research topics o Teach you how to do OS research New goals o Common foundation for OS and database research o Motivation OS and DB communities historically separate despite much overlap in goals and ideas We often use independent vocabulary and have largely separate classic papers that the other community typically hasn t read especially OS people not reading DB papers since a DB is just an application o Part 1 of a year long advanced systems course o 262A satifies software breadth requirement by itself Research analysis synthesis o Analysis understanding others work both what s good AND what s bad o Systems research isn t cut and dried few provably correct answers o Synthesis finding new ways to advance the state of the art 1 Lecture 1 2 parts to course o literature survey o term project Will not cover basic material Analysis literature survey read analyze criticize papers o All research projects fail in some way o Successful projects got some interesting results anyway In class lecture format with discussion Synthesis do a small piece of real research o o o o Suggested projects handed out in 3 4 weeks Teams of 2 3 Poster session and conference paper at the end of the semester Usually best papers make it into a real conference with extra work Class preparation o Reading papers is hard esp at first o Read before class Homework brief summary paper o 1 2 page or less o 2 most important things in paper o 1 major flaw Course topics o o o o o o o much of systems design is about sharing File systems Virtual memory Concurrency scheduling synchronization Communication Multiprocessors Distributed Systems Transactions recovery fault tolerance 2 Lecture 1 o Protection security o OS structure o Revealed truth overall principles Grad class material may be controversial hopefully Lecture format cover 1 2 papers plus announcements Grading 50 project paper 15 project demo 25 midterm 10 paper summaries o can miss 3 summaries without penalty no reason needed or wanted o Summaries 1 2 page at least one criticism summary should be at most half Reading list o o o o No textbook Almost everything is online otherwise I ll distribute copies in class Warm up paper UNIX timesharing Reading for next time System R paper in the Red Book II The UNIX Time Sharing System Warm up paper Material should mostly be a review Classic system and paper described almost entirely in 10 pages Key idea elegant combination of a few concepts that fit together well System features o o o o o time sharing system hierarchical file system device independent I O shell based tty user interface filter based record less processing paradigm Version 3 Unix o o o o ran on PDP 11 s 50 KB 2 man years to write written in C 3 Lecture 1 File System o ordinary files uninterpreted o directories protected ordinary files o special files I O Directories o o o o o o root directory path names rooted tree current working directory back link to parent multiple links to ordinary files Special files o uniform I O model o uniform naming and protection model Removable file systems o tree structured o mount ed on an ordinary file Protection o user world RWX bits o set user id bit o super user is just special user id Uniform I O model o open close read write seek o other system calls o bytes no records File system implementation o table of i nodes o path name scanning 4 Lecture 1 o mount table o buffered data o write behind I node table o short unique name that points at file info o allows simple efficient fsck o can t handle accounting issues Processes and images o o o o o o o text data stack segments process swapping pid fork pipes exec file arg1 argn pid wait exit status The Shell o o o o o cmd arg1 argn stdio I O redirection filters pipes multi tasking from a single shell shell is just a program Traps o hardware interrupts o software signals o trap to system routine 5