nOS

An attempt to make a CLI operating system

version notation: x.y.z (x=major_release ; y=minor_features ; z=patch)

Steps to making it: (each step should be its own commit, or a tag (if it is more complex and achieves a milestone)) (The Engineering Methodology is Incremental)

1. Make a dockerfile to setup cross-compile build environment
2. PoC bootable loop program with a message
3. Create makefile that builds the PoC into image (tag: 0.0.0)
4. From the Bootloader, load the kernel into memory and jump there
5. Bootloader transitions to protected mode before jumping to kernel
6. Change kernel from assembly to C program
7. IDt

Some Goals

Make All Standard Iterrupt Service Routines

Create "USERLAND"

Make POSIX conforming sytem calls

make a shell with standardized std:in & std:err

Testing

• Build Infrastructure to Run Unit & Integration Tests in intended ISA from Qemu (in a regular OS such as debian)
• Link emulated OS std:in/std:err with hosts std:in/std:err, to streamline testing
• Run Systems Tests from Qemu

GUI

docker build -t nos-buildenv .

docker run --rm -it -v $(pwd):/root/env nos-buildenv or docker run --cpus="15" -m 10g --rm -v $(pwd):/root/env -w /root/env nos-buildenv make

qemu-system-x86_64 -drive format=raw,file=build/nos.img -display curses To exit qemu: ALT-2 then type quit

Instruction for the Makefile

1. build kernel
2. assemble kernel_start.asm
3. compile kernel.cpp
4. link them
5. assemble bootloader
6. concatenate bootloader with kernel and truncate the result