mos

My attempt to write a small operating system (and to try Rust :) ).

mos

mOS boot log

Development

Start QEMU with mOS inside:

make run

Run tests:

make tests

Folders structure

• ./initrd: all files in this directory will be placed into a single archive and mounted as a TarFS to /initrd
• ./src: kernel source code
• ./lib: Contains userspace programs and librust: Rust library to write programs for mOS.

OS Entrypoint: /src/lib.rs.

Requirements

• Cross compiled binutils (actually only ld): docs/binutils.md
• NASM
• Rust nightly (I use nightly-2019-11-04)
• Docker to build iso with GRUB bootloader
• QEMU
• gnu-tar on MacOS (brew install gnu-tar)

librust

You can build userspace programs for mOS. To communicate with OS from Rust code you need to use librust. It is a library which provides interface to use all implemented system calls.

What can it do?

• Load! :-)
• Print to VGA buffer
• Mount ramdisk
• Built-in support for TarFS
• Interrupts
• System clock
• Syscalls ABI
• Processes support, context switching
• Start init process
• Shell for user's commands: msh

ToDo

• Fix paging. It does not work properly, and because of that it's not possible to start separate processes. Now programs are being running as threads inside the OS.
• After paging mmap call in the librust must be completed, so it will be possible to request memory from userspace.
• Higher Half Kernel
• fork syscall ...