You'll use two sets of tools in this class: an x86 emulator, QEMU, for running your kernel; and a compiler toolchain, including assembler, linker, C compiler, and debugger, for compiling and testing your kernel. Here's the information you'll need to download and install your own copies. This class assumes familiarity with Unix commands throughout.
A "compiler toolchain" is the set of programs, including C and C++ compilers, assemblers, and linkers, that turn code into executable binaries. You'll need a compiler toolchain that generates code for 32-bit Intel architectures ("x86" architectures) in the ELF binary format. We recommend you configure one of your machines (such as a laptop) with a working toolchain, but if you cannot do this, the School of Engineering's SEASnet and a private class compute server will be made available shortly.
Test Your Compiler Toolchain
Modern Linux and BSD UNIX distributions already provide a toolchain suitable for CS 235. To test your distribution, try the following command:
% objdump -i
If the second line is elf32-i386, you're all set, and don't need to compile your own toolchain.
Using a Virtual Machine
Otherwise, the easiest way to get a compatible toolchain is to install a modern Linux distribution on your computer. With platform virtualization, Linux can cohabitate with your normal computing environment. Installing a Linux virtual machine is a two step process. First, you download the virtualization platform.
VirtualBox is a little slower and less flexible, but free!
Once the virtualization platform is installed, download a boot disk image for the Linux distribution of your choice.
This will download a file named something like ubuntu-10.04.1-desktop-i386.iso. Start up your virtualization platform and create a new (32-bit) virtual machine. Use the downloaded Ubuntu image as a boot disk; the procedure differs among VMs but is pretty simple. Type objdump -i, as above, to verify that your toolchain is now set up. You will do your work inside the VM.
Building Your Own Toolchain
This will take longer to set up, but give slightly better performance than a virtual machine, and lets you work in your own familiar environment. (Mac/Unix Only)
We assume that you are installing the toolchain into /usr/local. You will need a fair amount of disk space to compile the tools (around 1GiB). If you don't have that much space, delete each directory after its make install step.
Download the following packages:
Unpack and build the packages. The green bold
text shows you how to install into
We provide a patched version of the QEMU emulator with improved support for debugging. (Credit to Kohler and Austin Clements and others at MIT 6.828.) We recommend you compile QEMU from this source; if you use the version that came installed on your Linux distribution, you will not be able to complete all the debugging exercises.
First, download the source:
On a Linux machine, you will need to install the SDL graphics library to build QEMU. On Ubuntu or Debian:
sudo aptitude install libsdl1.2-dev
Then unpack, compile, and install QEMU as follows.
tar xjf qemu-0.12.5-aos.tar.bz2 cd qemu-0.12.5-aos On Mac OS X: ./configure --prefix=/usr/local --disable-sdl --enable-cocoa \ --disable-docs --target-list="i386-softmmu x86_64-softmmu" On Linux: ./configure --prefix=/usr/local --target-list="i386-softmmu x86_64-softmmu" make make install # This step may require privilege (sudo make install)
The QEMU monitor is accessible by pressing Ctrl-Alt-2 inside the QEMU window. Return to normal display with Ctrl-Alt-1. QEMU tends to take control of your mouse. If you can't find a mouse pointer, check the QEMU title bar for text like "Press Ctrl-Alt to exit grab" and, if so, press Ctrl-Alt to regain control.
Source Code Control
You will do your work using a source code control system. This will help you maintain two parallel branches—one with your changes, and one with the labs as we release them. We will support two source code control systems: CVS and Git. Git is by far the better system, and strongly preferred by your instructor for his own work, but this is the first time we're trying it in CS 235, so it will be more experimental.
You don't need to compile CVS or Git yourself. The packaged versions that come with your OS will be good enough. You just need to install them.
Using Cygwin on a Windows Machine
If you have a Windows machine, but cannot run a Linux virtual machine or install a dual-boot configuration, the easiest way to work on labs from home will be to use a class compute server or SEASnet coupled with VNC remote display. Let us know as soon as possible if you want this configuration to work.
Nevertheless, it should be possible to execute many of the above steps and get a functional build environment running on Windows using Cygwin. Here's how to install Cygwin on your Windows machine.
You should also be able to compile the class tools and the labs on your Windows machine, once Cygwin has been installed. Let us know if you have success with this.
Using the Class Compute Server
A compute server is available for your use. Request a login from your instructor; your mail should include your preferred username and an SSH public key (use PuTTY on Windows [PuTTY authentication notes]).
VNC is a compressed remote desktop viewing protocol that QEMU understands. Using VNC will be faster; QEMU is very slow over a remote X connection. You will need a VNC viewer on your local computer. Good, free viewers are available for Linux, Mac OS X, and Windows.
When the instructor creates your account, you'll receive a VNC port allocation (something like 5500). Remember this number; we call it VNCPORT below.
Using X windows
This may be simpler if you have trouble finding a VNC viewer. Simply start up an X server and run
ssh -Y seek.cs.ucla.edu
Do your work as usual. The -Y option will forward QEMU's window onto your local display. Try make run-nox if you don't need the QEMU window.