BeyondOS

A simple, modular operating system for the RISC-V 32-bit architecture. This repository extends from OS in 1000 lines with improved clarity and extendability.

Features

• Process Management: Context switching and cooperative multitasking
• Virtual Memory: Page table for virtual address and physical address translation
• System Calls: User-kernel mode transitions
• File System: Simple file system in .tar with read/write operations via VirtIO disk

Planned Features

• Memory Allocator: The memory allocator in BeyondOS currently support page allocation only, without release functionality. It's planned to design a more generalized allocator with buddy system
• Scheduler: BeyondOS supports cooperative multitasking. It's time for the operating system to support preemptive scheduling

Project Organization

.
├── common.c
├── common.h
├── disk                # example disk
│   ├── hello.txt
│   └── meow.txt
├── kernel
│   ├── file.c          # file system
│   ├── file.h
│   ├── kernel.c        # kernel main
│   ├── kernel.h
│   ├── kernel.ld       # kernel linker script
│   ├── kio.c           # kernel input/output
│   ├── kio.h
│   ├── memory.c        # manage the memory allocate
│   ├── memory.h
│   ├── process.c       # process and context switching
│   ├── process.h
│   ├── syscall.c       # system call implementation
│   ├── syscall.h
│   ├── trap.c          # trap and exception handling
│   ├── trap.h
│   ├── virtio_disk.c   # VirtIO_disk driver
│   ├── virtio_disk.h
│   ├── vm.c            # page table management
│   └── vm.h
├── user
│   ├── shell.c         # simple shell implementation
│   ├── user.c          # user space library functions
│   ├── user.h
│   └── user.ld         # user program linker script
├── Makefile
└── README.md

Getting Started

Installation

1. Clone the repository

git clone https://github.com/ilsao/BeyondOS.git
cd BeyondOS

2. Install dependencies

sudo apt update && sudo apt install -y clang llvm lld qemu-system-riscv32 curl
curl -LO https://github.com/qemu/qemu/raw/v8.0.4/pc-bios/opensbi-riscv32-generic-fw_dynamic.bin

Running

Build and run the OS:

make 

Clean build artifacts:

make clean

BeyondOS provides these commands:

• hello - Test printf functionality
• readfile - Read hello.txt from disk
• writefile - Write content to hello.txt
• exit - Exit the shell program