This are some notes for the course OS 161 from ops-class.org (based on the OS 161 course from Harvard).
#Geting started
You will need some tools. A nice Text Editor or a fancy IDE for C, I usually go for gedit, or sometimes vim.
Then you will need to install all the toolchain for the course plus some other tools
yaourt -S mips-harvard-os161-binutils mips-harvard-os161-gcc48 mips-harvard-os161-gdb sys161 bmake git wget
The first three (*-binutils *-gcc48 *-gdb) are the assembler, linker, crosscompiler and the debugger that will help you to develop the OS.
sys161 It's the simulator for the Mips Architecture that will run the OS.
bmake is a bsd version of make, in general you will have GNUMake in your system, but it uses different syntax so you need bmake to build the system.
git is a program for version control, you should know.
wget it's a tool to download things.
#Get the sources
Go to the folder you want to download the sources for the kernel and use git
cd ~/src
git clone https://github.com/ops-class/os161.git
The symbol ~ is a short hand for my home directory /home/user, so that's equivalent to cd /home/user/src
Now this creates the folder os161 inside of /home/user/src
#Configure the OS
Now we need to configure the OS so bmake can build all the things.
Go to the main directory of your sources
cd /home/user/src/os161
So this time we need to call the configure script, as you can see if you use ls there is configure.
It only takes one parameter --ostree this indicates were we want bmake put all the things. In general
you want this in the root subdirectory.
./configure --ostree=$(realpath ./root)
realpath takes an argument and append the whole rute of your current directory in this case /home/user/src/os161/root
After run configure, a new file defs.mk is created.
#Configure the Kernel
We not only need to configure the OS, we need to configure the kernel too. We need to go to the Kernel's configuration subdirectory.
cd kern/conf
And tell the configure script what kind of configuration we want. For the Assignature 0, ASST0 we want DUMBVM
./config DUMBVM
#Making all the things
Now we need to call bmake. We will need three steps. One to make all the dependencies, make the kernel and move all the files to the appropiated location (the osstree we defined before).
We need to go to the compile directory of our kernel.
cd ../compile/DUMBVM
And make make make all the things.
First all the dependencies.
bmake depend
If no error, now we need to make the kernel
bmake
And again if no errors move the things, in this case we need to run bmake install
bmake install
If everything went fine, now we have our vm almost ready to run.
Go to the root directory or the directory you defined as osstree
cd ../../../root
#Run the Simulator
Now there's only one more thing to do, we need a more configuration file, that will set some parameters for our simulator.
Make sure you are in the root subdiretory of the os161 folder and download the configuration file.
wget https://www.ops-class.org/files/sys161.conf
With everything set up, just fire the Simulator
sys161 ./kernel