Brew OS

Scope

Brew OS is a hobby operating system project designed for educational purposes to explore core OS concepts including kernel development, process management, memory management, and system-level programming. It's a work in progress.

Requirements

• *nix-based development environment (Linux/MacOS/MSYS2)
• GCC cross-compiler targeting i686
• GNU Binutils tageting i686
• GNU Make
• QEMU (for emulation and testing)

Build Instructions

Build the Project

make

Run in Emulator

make run

Clean Build Artifacts

make clean

Project Structure

brew-os/
├── kernel/           # Kernel code
|   ├── arch/         # Architecture specific code
|   ├── boot/         # Bootloader code
|   ├── drivers/      # Hardware driver code
|   ├── fs/           # Filesystem(s) code
|   ├── include/      # Header files
|   ├── kernel/       # Kernel entry point and misc code
|   ├── lib/          # Freestanding C library code
|   ├── mm/           # (non-arch specific) memory management code
|   ├── linker.ld     # Linker script
|   └── Makefile      # Build configuration
└── README.md         # This file

TODOs

• Improve memory management:
  • Add paging-aware allocator hooks (slab/buddy) so drivers and filesystems can request page-aligned buffers
  • Extend memory_bytes_* stats with fragmentation metrics
  • Implement virtual memory and memory protection systems: per-process page tables, copy-on-write primitives, and guard pages around the kernel heap to catch overflows early.
• Process management and scheduling:
  • Implement a task structure with saved registers, stack setup, and a round-robin scheduler
  • Wire an iret-based context switch from the PIT interrupt handler
• Device drivers
  • Implement a generic character/block device registry with dev-style naming so new drivers (serial, mouse, network) can plug in without touching the shell
  • Generalize filesystem layer: add a VFS interface to multiplex FAT/EXT2 and implement writable EXT2
  • Cache directory entries and support write-back buffers
  • Fix issues with the floppy driver
  • Implement more devices (Mouse input, serial ports, USB, Audio, ...)
  • Implement a modular driver/kernel extension system
• Userland
  • Separate shell from kernel code, and split shell into multiple executables (ls, echo, touch, ...)
  • Implement a bash-like shell with scripting capabilities, piping and redirection, ...
  • Implement more tools and commands (hexdump, text editor, pwd, ...)
  • Remove demo code from kernel sources
• Diagnostics and logging
  • Add a ring-buffered kernel log with severity levels, expose it over serial for cross-machine debugging
  • Extend panic() to dump register state/stack traces
• Miscellaneous
  • Improve POSIX/UNIX compliance

And much much more...