First Day
Setting Up
Start by setting up a dev container for Linux, MacOS, Windows. You will need VSCode and Docker to use the provided devcontainer (in the git repo).
Troubleshooting
If there are any issues, check out the troubleshooting guide and ask us questions.
Checkout code
The kernel is hosted on GitHub so if you haven't already downloaded the code, here is how:
git clone https://github.com/UMN-Kernel-Object/ukoos.git
cd ukoos
Compiling
Once we have the code and tools, we can compile the code from the dev container
mkdir build
cd build
../configure
make
Running
Once the kernel is built, we can run the code inside a virtual machine (qemu)
make qemu
Debugging
From the first terminal run qemu, but we need to add options to enable debugging
make qemu-debug
Which will be controlled by GDB once we start it here (from a new shell)
make gdb
The first terminal, running make qemu-debug will look similar to the video below. However, it won't do anything until you run make gdb in the second window.
And the second, running make gdb
The gdb window will be how you will control the OS (with the controls below) but the output will show up in the first. There is a more detailed guide on using gdb, but here are the basics:
| Command | Meaning |
|---|---|
| n | next line |
| s | step (like next line, but enters function calls) |
| c | continue until next breakpoint (or end) |
| b | add breakpoint at current point |
| b symbol | add breakpoint to symbol (symbol is a function name, etc.) |
| p variable | print the value of the C variable |
Fixing a bug
Checking out the first day code
Switch to the tutorial code
git checkout tutorials/first-day
Please note, do not run the ./configure script from the tutorials/first-day branch, it will make the following commands not work.
and rebuild
cd build
make
Once you have the code and are able to run and debug, you'll notice that "Hello, World!" is misspelled! Try using the debugger to step through and find the line that prints this out incorrectly, then go to the file, edit it, and re-run.