CS330 Project: Pintos Overview

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CS330 Project Pintos Overview
??? Computer Architecture Lab. (Division of
Computer Science, KAIST)
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Welcome to Pintos World!

• What is Pintos?
• An instructional operating system
• Developed by Stanford university
• A few of the source files are derived from code
  used in the MIT OS course
• A real OS for 80x86 architecture (c.f. nachos)
• Run on a regular IBM-compatible PC or an x86
  simulator
• The original structure and form was inspired by
  the nachos
• Written in C language
• These projects are hard. Hang on!

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Project Schedule

• Project 0 Warming-up (1 week)
• Project 1 Threads (2 weeks) ??? ??
• Project 2 User Programs (3 weeks) ??? ??
• Project 3 Virtual Memory (5 weeks) ??? ??
• Project 4 File System (3 weeks)

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System Startup (1/5)

• Overview
• BIOS
• Boot Loader
• Kernel Initialization

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System Startup (2/5)

• The BIOS
• The CPU initializes itself and then executes an
  instruction at a fixed location (0xffff ffff0)
• This instruction jumps into the BIOS
• The BIOS finds a boot device and loads its first
  sector into memory
• Starting from physical address 0x0000 7c00
• The first sector contains the Pintos loader
  (threads/loader.S)
• The BIOS transfers control to the loader

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System Startup (3/5)

• The boot loader
• Enables memory accesses beyond first 1 MB
• For historical reasons, this initialization is
  required
• Asks the BIOS for the PCs memory size
• Again for historical reasons, the function we use
  can only detect up to 64MB of RAM (This is the
  limit that Pintos can support)
• The memory size is stored in the loader that the
  kernel can read after it boots
• Creates a basic page table
• This page table maps the 64 MB at the base
  (starting at virtual address 0) directly to
  identical physical address
• It also maps the same physical memory starting at
  virtual address LOADER_PHYS_BASE (0xc000 0000)

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System Startup (4/5)

• The boot loader (contd)
• Turns on protected mode and paging
• Interrupts are still disabled
• Loads the kernel from disk
• Assumptions
• The kernel is stored starting from the second
  sector of the first IDE disk
• The BIOS has already set up the IDE controller
• The loader loads the kernel starting 1 MB into
  physical memory
• Jumps to the start of compiled kernel image
• Using the linker script (thread/kernel.lds.S)

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System Startup (5/5)

• Kernel initialization
• Clearing BSS, and get machines RAM size
• Initializing threads system
• Initializing VGA, serial port, and console
• To print a startup message to the console
• Greeting user and reading kernel command line
• Kernel command line
• Initializing memory system
• Initializing random number generator and
  interrupt system
• Starting thread scheduler and enabling interrupts
• Initializing file system

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Environments

• Bochs
• IA-32 emulator
• We will run Pintos on this emulator
• Bochs makes it easy to develop and debug Pintos
  projects
• Linux Bochs
• If you have an available Linux machine, we
  recommend this environment

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Linux Bochs (1/4)

• Linux
• If you will use cc12-14 nodes, you may skip this.
• Install a proper Linux distribution on your
  machine
• Such as Fedora, Debian, Ubuntu, or whatever you
  like
• You can use a pre-installed Linux machine
• Install X development libraries
• Install development tools
• Including gcc, make, perl, gdb (option) and so
  on

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Linux Bochs (2/4)

• X Window Server to the Windows
• Xmanager recommended
• Xmanager Enterprise 2.1
• Xming
• VNC
• Or similar

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Linux Bochs (3/4)

• Bochs
• If you will use cc12-14 nodes, you may skip this
  installation.
• Get the source (the 2.2.6 version)
• http//bochs.sourceforge.net/getcurrent.html
• Install bochs
• Must use patches in pintos.
• Using script. ( pintos/src/misc/bochs-2.2.6-build.
  sh )
• yjlee_at_cc14 misc ./bochs-2.2.6-build.sh
• usage env SRCDIRltsrcdirgt
  PINTOSDIRltsrcdirgt DSTDIRltdstdirgt sh
  ./bochs-2.2.6-build.sh
• where ltsrcdirgt contains bochs-2.2.6.tar.gz
• and ltpintosdirgt is the root of the pintos
  source tree
• and ltdstdirgt is the installation prefix (e.g.
  /usr/local)
• yjlee_at_cc14 miscenv SRCDIR/home/yjlee/bochs-2.2
  .6/ PINTOSDIR/home/yjlee/pintos
  DSTDIR/usr/local/ sh /home/yjlee/pintos/src/bochs
  -2.2.6-build.sh
• Maybe need the latest version of Binutils Make.

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Linux Bochs (4/4)

• Pintos
• Get the source
• http//www.stanford.edu/class/cs140/pintos/pintos.
  tar.gz
• Extract the source for Pintos into pintos/src
• tar xzf pintos.tar.gz
• Test your installation
• cd pintos/src/threads
• make
• ../utils/pintos run alarm-multiple

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Building Pintos

• Building Pintos
• Use make command in each of project folders
• threads, userprog, vm, and filesys
• Interesting files (in the build directory)
• kernel.o, kernel.bin, loader.bin, and os.dsk

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Running Pintos

• Running Pintos
• Add pintos/src/utils folder to PATH
• Execute pintos option -- argument
• Option
• Configuring the simulator or the virtual hardware
• Argument
• Each argument is passed to Pintos kernel verbatim
• pintos run alarm-multiple instructs the kernel
  to run alarm-multiple
• Pintos script
• Parse command line
• Find disks
• Prepare arguments
• Run VM (bochs)

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Grading

• Testing
• make check (in build directory)
• Design
• Demonstration
• Design document
• Data structure
• Algorithm
• Synchronization
• Rationale
• Source code
• Refer to the pintos document by Ben Pfaff

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Misc.

• Project documentation
• Refer to Appendix D in the pintos document
• Coding standard
• Style
• C99
• Unsafe string functions

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Useful Tools

• Gdb
• The GNU Project debugger, allows you to see what
  going on inside another program while it executes
• Tags
• An index to the functions and global variables
• make tags in pintos/src
• CVS
• A version control system

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Cheating

• What is cheating?
• Any attempt to represent another persons work as
  your own
• What is not cheating?
• Helping others use systems or tools
• Helping others with high-level design issues
• Helping others debug their code
• Sharing useful information for the problem
• Cheating will not be tolerated in this course!
• Anyone who involved in cheating will be penalized

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Project 0 Warming-up (1/2)

• Prepare your environment
• Choose an development environment for Pintos
• Install the required tools and Pintos
• Assignments
• Test your installation and capture it
• The capture(s) should contain
• Your OS (Linux, and so on)
• A result of Pintos execution
• pintos run alarm-multiple (in pintos/src/threads
  folder)

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Project 0 Warming-up (2/2)

• Assignments (contd)
• Write a document about how the above test works
• Add a new test program
• A new test prints hello, world! (refer to
  pintos/src/tests/threads)
• You should submit screen shot(s) of a result of
  the following command
• pintos run hello (in pintos/src/threads folder)
• Due data
• 4/7 (Sat) ??, email to yjlee_AT_camars.kaist.ac.kr