1 / 38

Operating System NachOS Project

Operating System NachOS Project. 教授：周立德 老師. 行動寬頻網路實 驗室 太空遙測研究中心 R3-305 分機： 57968 Email: kkw@networklab.csie.ncu.edu.tw. Outline. What is NachOS How does NachOS work Source Tree System Starting Install NachOS Projects Installation Multiprogramming Scheduling. What is NachOS.

nerita
Download Presentation

Operating System NachOS Project

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Operating System NachOS Project 教授：周立德 老師 行動寬頻網路實驗室 太空遙測研究中心 R3-305 分機：57968 Email: kkw@networklab.csie.ncu.edu.tw

  2. Outline • What is NachOS • How does NachOS work • Source Tree • System Starting • Install NachOS • Projects • Installation • Multiprogramming • Scheduling

  3. What is NachOS • Not Another Completely Heuristic Operating System • Written by Tom Anderson and his students at UC Berkeley in 1992 http://www.cs.washington.edu/homes/tom/nachos/

  4. What is NachOS • An educational OS used to • Teach monolithic kernel design and implementation • Do experiments, you can (and will) modify and extend it • Fact • Real hardware is difficult to handle • May break if handled wrong

  5. What is NachOS • Approach • Use a virtual MIPS machine • Provide some basic OS elements • Includes many facets of a real OS: • Threads • Interrupts • Virtual Memory • I/O driven by interrupts

  6. What is NachOS • NachOS also contains some hardware simulation • MIPS processor • Can handle MIPS code in standard COFF, except for floating point instructions • You can (and will) write code in C/C++, compile it to MIPS and run it on NachOS • Console, Network interface, Timer

  7. How does NachOS work • Run as a single UNIX process • Provide a skeletal OS that supports • Threads • User-level processes • Virtual memory • Interrupt-driven I/O devices

  8. How does NachOS work • Two modes of execution • NachOS kernel • Executes when • NachOS starts up • A user-program causes a software trap (page fault, syustem call, etc.) • MIPS simulator • Initialized and started by NachOS kernel

  9. How does NachOS work

  10. How does NachOS work • Simulates MIPS architecture on host system (UNIX / Linux / Windows / MacOS X) • User programs need a cross-compiler (target MIPS) • NachOS appears as a single threaded process to the host operating system

  11. How does NachOS work

  12. How does NachOS work

  13. How does NachOS work

  14. Source Tree Root directory C++ introduction to teach how to write C++ Root directory of Nachos’s source code The tool to convert user programs from MIPS’s COFF into NachOS’s NOFF (NachOS Object File Format ) format File system Nachos’s library Source code of NachOS kernel and MIPS simulator MIPS machine In/Out message queues NachOS’s sample user programs threads User programs’ interfaces: system calls, address space,noffformat

  15. Start up interrupt handling initialize the ready queue and scheduler initialize MIPS machine Run some system testing System Starting > ./nachosstart code/threads/main.ccmain create kernel object initialize the system Invoke user program No user program Load user program System halt and terminate Run user program

  16. Install NachOS • Platform: Linux or Linux over VMware • RedHat Linux 9.0 • Install steps • Get NachOS-4.0 • wgethttp://140.115.155.199/2012_os/file/nachos-4.0.tar.gz • Get Cross Compiler • wget http://140.115.155.199/2012_os/file/mips-decstation.linux-xgcc.gz • Move Cross Compiler to / (根目錄) • mv ./mips-decstation.linux-xgcc.gz / • Untar Cross Compiler • cd / • tar zxvf /mips-decstation.linux-xgcc.gz

  17. Install NachOS • Untar NachOS-4.0 • tar zxvf ./nachos-4.0.tar.gz • Make NachOS-4.0 • cd ./nachos-4.0/code • make • Test if installation is succeeded • cd ./userprog • ./nachos -e ../test/test1 • ./nachos -e ../test/test2 • You should see the following…

  18. The test1 result Total threads number is 1 Thread ../test/test1 is executing. Print integer:9 Print integer:8 Print integer:7 Print integer:6 return value:0 No threads ready or runnable, and no pending interrupts. Assuming the program completed. Machine halting! Ticks: total 200, idle 66, system 40, user 94 Disk I/O: reads 0, writes 0 Console I/O: reads 0, writes 0 Paging: faults 0 Network I/O: packets received 0, sent 0

  19. The test2 result Total threads number is 1 Thread ../test/test2 is executing. Print integer:20 Print integer:21 Print integer:22 Print integer:23 Print integer:24 Print integer:25 return value:0 No threads ready or runnable, and no pending interrupts. Assuming the program completed. Machine halting! Ticks: total 200, idle 32, system 40, user 128 Disk I/O: reads 0, writes 0

  20. Operate NachOS • NachOS command help • ./nachos -h • Debugging mode • ./nachos -s • Execute files on NachOS • ./nachos -e ../test/test1

  21. Operate NachOS • 各個部分的編譯運行 • Nachos的各個部分都可以獨立編譯運行，也可以同時編譯各個部分。全部編譯可以採用如下命令： • code]# make • 當需要單獨編譯執行緒管理部分時，先進入threads目錄，然後採用如下命令： • threads]# make depend • threads]# make nachos

  22. Recompile Modified NachOS Code • cd nachos-4.0/code • make clean (optional) • make • If you want to fully re-compile the source code, “make clean” is required. Or make will only re-compile the modified and related files. (save time)

  23. Trace NachOS • Read *.h and *.cc to have an overview about the whole system and see how it is implemented • Documentation (A Road Map Through NachOS) • http://www.cs.duke.edu/~narten/110/nachos/main/main.html

  24. Project 1 - Installation • NachOS 介紹 • 安裝 NachOS，環境，過程 • 把安裝過程抓圖作成說明文件 (word 檔) • 利用Print Screen Button(請勿使用Alt+ Print Screen) • 把所有在 linux 下用到的指令解釋清楚其用法，並舉例說明

  25. Project 2 - Multiprogramming • 到 nachos-4.0/code/userprog 目錄下執行 • ./nachos –e ../test/test1 –e ../test/test2 Total threads number is 2 Thread ../test/test1 is executing. Thread ../test/test2 is executing. Print integer:9 Print integer:8 Print integer:7 Print integer:20 Print integer:21 Print integer:22

  26. Race Condition

  27. Project 2 - Multiprogramming • Please trace the following files to see why the output results are wrong • nachos-4.0/code/userprog/addrspace.h • nachos-4.0/code/userprog/addrspace.cc • nachos-4.0/code/userprog/userkernel.cc • nachos-4.0/code/machine/translate.h • Nachos-4.0/code/machine/translate.cc

  28. Project 2 - Multiprogramming • Please modified the Nachos code to run the correct results • You may need to modify the following functions • nachos-4.0/code/userprog/addrspace.cc

  29. Project 3 - Scheduling • Implement system call “Sleep” • Implement Multilevel Queue Scheduling (three Queue) • Non-preemptive Shortest-Job-First Scheduling (1 Queue) • First-Come, First-Served Scheduling (2 Queue) • Round-Robin Scheduling (3 Queue)

  30. System call “Sleep” • 請實作 Sleep(int x) 這個 system call, 把呼叫這個 system call 的 thread block住, 並且在 x 次的 timer interrupts 以後才又回到 READY 的狀態。

  31. System call “Sleep” (cont.) • 修改 exception.cc, syscall.h, start.s • 呼叫 alarm.cc 的 WaitUntil(int x) 來處理 Sleep(int x) 這個 system call

  32. SJF Scheduling • NachOS 內定的 scheduling algorithm 是 Round-Robin，請設計 non-preemptive SJF Scheduling • 請自行設計一組或多組 test case 來證明你的 project 是對的，針對 FCFS、RR 或是 SJF 都要能運作，放到 NachOS 下面去執行的 thread，每個Queue個數至少 3 個

  33. SJF Scheduling (cont.) • 由於是 non-preemptive，所以當 timer interrupts 時不用將 thread yield • 什麼時候有可能換 thread 執行？ • 需要記錄每個 thread 實際 CPU burst 長度 (timer interrupts 數目), 與預測將來 CPU burst 長度 • 在哪裡可以得到這個資訊？ • 何時該進行預測？

  34. Begin Running Invoke Sleep(x) Per timer interrupt: 1.Record actual CPU burst 2.叫醒應該起床的 threads 1.Set next predicted CPU burst 2.Insert this thread to Sleeping thread lists 3.Invoke thread->Sleep SJF Scheduling (cont.)

  35. Demo • 報告內容 • Project1 安裝過程介紹 • Project2 執行結果證明 • Project3 主程式介紹、執行結果證明 • 未完成項目和遭遇困難說明 • 把寫好的source code與報告(word檔)壓縮成 ”學號.tar.gz”，email to: kkw@networklab.csie.ncu.edu.tw

  36. Demo (cont.) • 郵件主旨請定為 • NachOS project #NO.，學號：姓名 • Ex: NachOS project #1，965402001:周立德 • 助教收到 email 後會回信表示收到 • 如果一週內沒收到回信，請再寄一次

  37. Something you need to know • Don’t modify the files under “machine” directory. • Please keep a copy of your code in your own PC. Course machine is for coding and testing. We don’t guarantee the safety of your codes.

  38. References • http://www.cs.washington.edu/homes/tom/nachos/ • http://inst.eecs.berkeley.edu/~cs162/sp08/Nachos/ (JAVA NachOS) • http://www.student.cs.uwaterloo.ca/~cs350/common/install.html Installation: • http://flyingwinnie.blogspot.com/2008/05/nachos.html redhat 9.0 • http://www.youtube.com/watch?v=epT7eFJLxls ubuntu 11.04 • http://www.student.cs.uwaterloo.ca/~cs350/common/install.html ubuntu 10.10 • http://www.youtube.com/watch?v=plGyUq4PcVA ubuntu 10.10

More Related