LinuxMacOS_Build.md

Welcome to the Linux / MacOS build instructions

Important

It is always wise to verify script contents before running

# 1. Clone the repo with depth 1 (we dont need the git history here)
$ git clone https://github.com/rfmineguy/2024_barebones_os.git --depth=1

# 2. Retrieve and setup the docker image require to build this project
#  - This step requires docker to be installed
#  - This step also pulls down and generates an image that is around 1GB in size
$ ./scripts/build.sh docker_get 

# 3. Create fat drive to mount in qemu and use as the active drive for the kernel's operations
#  - This step isn't technically mandatory, but the kernel does a lot more if you do this step
$ ./scripts/build.sh create_disk

# 4. Build the iso file
#  - This step uses the previously built docker image and the software installed
#      to it to build the c source files with a i686-elf cross compiler toolchain
$ ./scripts/build.sh build

# 5. Verify that the iso file is multiboot1 compatible (multiboot2 might be in the future) 
#  - If this indicates that its not multiboot compatible, I broke something (oops)
#  - This step uses the previously built docker image and the software installed
#      to it to check if the generated iso image contains valid multiboot headers
$ ./scripts/build.sh checkmboot

# 6. Finally run the kernel in qemu
#  - This step uses qemu-sysstem-i386 to run the kernel iso
#  - The i686 and i386 architectures are mostly compatible with each other
$ ./scripts/build.sh qemu

Bonus

So the filesystem is created on the host machine, which means we can add more files to it during the build phase. To do this you need to edit scripts/debian.Makefile

1. Look for the section titled `create_fat_fs` 
2. Add a new `mcopy` where you replace the `fatfiles/name.txt` with your file and replace `"::name.txt"` with your filename
    a. Note: It's important that this new line is formatted as such
       mcopy -i out/main.img fatfiles/new.txt "::new.txt"