Getting Started

To get started, you'll have to log into a machine that Pintos can be built on. You may use given Linux machines by the intructors or your own Solaris or Linux machines. However, we will test your code on given machines, and the instructions given here assume this environment. We cannot provide support for installing and working on Pintos on your own machine. Belows server environment will be given to each student.

Now you can get the source code for Pintos into a directory name 'pintos', by executing:

git clone

However, the source codes are likely to be changed before the project period, we recommend you to duplicate the repository. When we change the template code, you can easily synchronize your code with the template. Please NOT TO MAKE PUBLIC FORK. We will never change the source code during the project period, except for the critical bug lies on the template code.

FYI. We have tested the pintos code and the solution on the Ubuntu 16.04.6 LTS with gcc (gcc (Ubuntu 7.4.0-1ubuntu1~16.04~ppa1) 7.4.0) and qemu-system-x86_64 (QEMU emulator version 2.5.0 (Debian 1:2.5+dfsg-5ubuntu10.43)), same as the given linux machine.

Once you've retrived source code, you can set up your environment with below command in pintos root directory:

$ source ./activate

It is a good idea to add this line to the '.bashrc' in your home directory. Otherwise, you'll have to type it every time you log in.

Source Tree Overview

Let's take a look at what's inside. Here's the directory structure that you should see in pintos/

  • threads/: Source code for the base kernel, which you will modify starting in project 1.
  • userprog/: Source code for the user program loader, which you will modify starting with project 2.
  • vm/: An almost empty directory. You will implement virtual memory here in project 3.
  • filesys/: Source code for a basic file system. You will use this file system starting with project 2, but you will not modify it until project 4.
  • devices/: Source code for I/O device interfacing: keyboard, timer, disk, etc. You will modify the timer implementation in project 1. Otherwise you should have no need to change this code.
  • lib/: An implementation of a subset of the standard C library. The code in this directory is compiled into both the Pintos kernel and, starting from project 2, user programs that run under it. You should have little need to modify this code.
  • include/lib/kernel/: Parts of the C library that are included only in the Pintos kernel. This also includes implementations of some data types that you are free to use in your kernel code: bitmaps, doubly linked lists, and hash tables. In the kernel, headers in this directory can be included using the #include <...> notation.
  • include/lib/user/: Parts of the C library that are included only in Pintos user programs. In user programs, headers in this directory can be included using the #include <...> notation.
  • tests/: Tests for each project. You can modify this code if it helps you test your submission, but we will replace it with the originals before we run the tests.
  • examples/: Example user programs for use starting with project 2.
  • include/: Source code for the header files (*.h).

Building Pintos

As the next step, build the source code supplied for the first project. First, cd into the threads directory. Then, issue the make command. This will create a build directory under threads, populate it with a Makefile and a few subdirectories, and then build the kernel inside.

Following the build, the following are the interesting files in the build directory:

  • Makefile: A copy of pintos/src/ It describes how to build the kernel.
  • kernel.o: Object file for the entire kernel. This is the result of linking object files compiled from each individual kernel source file into a single object file. It contains debug information, so you can run GDB (see GDB) or backtrace (Backtraces) on it.
  • kernel.bin: Memory image of the kernel, that is, the exact bytes loaded into memory to run the Pintos kernel. This is just kernel.o with debug information stripped out, which saves a lot of space, which in turn keeps the kernel from bumping up against a 512 kB size limit imposed by the kernel loader's design.
  • loader.bin: Memory image for the kernel loader, a small chunk of code written in assembly language that reads the kernel from disk into memory and starts it up. It is exactly 512 bytes long, a size fixed by the PC BIOS. Subdirectories of build contain object files (.o) and dependency files (.d), both produced by the compiler. The dependency files tell make which source files need to be recompiled when other source or header files are changed.

Running Pintos

We've supplied a program for conveniently running Pintos in a simulator, called pintos. In the simplest case, you can invoke pintos as pintos argument.... Each argument is passed to the Pintos kernel for it to act on. Try it out. First cd into the newly created build directory. Then issue the command pintos run alarm-multiple, which passes the arguments run alarm-multiple to the Pintos kernel. In these arguments, run instructs the kernel to run a test and alarm-multiple is the test to run. Pintos boots and runs the alarm-multiple test program, which outputs a few screenfuls of text.

You can log serial output to a file by redirecting at the command line, e.g. pintos -- run alarm-multiple > logfile. The pintos program offers several options for configuring the qemu or the virtual hardware. If you specify any options, they must precede the commands passed to the Pintos kernel and be separated from them by --, so that the whole command looks like pintos option... -- argument.... Invoke pintos without any arguments to see a list of available options. Options includes: how you want VM output to be displayed: use -v to turn off the VGA display, or -s to suppress serial input from stdin and output to stdout. The Pintos kernel has commands and options other than run. These are not very interesting for now, but you can see a list of them using -h, e.g. pintos -h.

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