Apheleia operating system (AOS)

In Greek mythology, Apheleia (Ἀφέλεια) was the spirit and personification of ease, simplicity and primitivity in the good sense ... - Wikipedia

What is AOS?

Apheleia is a small UNIX-like hobby operating system made for fun and as a learning opportunity. It aims to be as minimalistic and simple as possible while still providing basic functionality.

The current tree supports x86_64, x86_32, riscv_64, and riscv_32 builds, x86 BIOS boot, RISC-V emulator and FRISC FPGA images, and a small windowed userland.

What does this repository include?

• the kernel source in kernel/
• the userspace tree in userland/{core,ui,tools,games}
• the staged root filesystem content in root/
• the libc and support libraries in libs/
• build, image, Docker, and emulator helpers in utils/
• some other small miscellaneous libs with common functions/macros

How to build and run?

Docker is the recommended first build path because it brings its own toolchain:

make docker_build

That builds the Docker image if needed and then builds AOS inside it. Use make docker_image only when you want to rebuild the container image without building the OS.

For a local Linux build, install the matching compiler, binutils, emulator, and image tools for the target architecture:

make all
make run

Build options are passed as normal make variables:

make all ARCH=x86_32
make ARCH=riscv_32 TOOLCHAIN=llvm run-spike
make all ARCH=riscv_32 TOOLCHAIN=llvm RISCV_FRISC=true
make all ARCH=riscv_32 TOOLCHAIN=llvm USERLAND=tcc
make all ARCH=riscv_32 TOOLCHAIN=llvm USERLAND=mbrot,tcc

Common build variables:

Variable	Default	Values	Notes
ARCH	x86_64	x86_64, x86_32, riscv_64, riscv_32	target architecture
TOOLCHAIN	gnu	gnu, llvm	compiler/toolchain family
IMAGE_FORMAT	img	img, iso	iso is for x86 images
PROFILE	fast	fast, normal, small, debug, debug_extra	optimization and debug level
RISCV_FRISC	false	true, false	build a FRISC FPGA image
USERLAND	default	default, all, core, or names such as mbrot,tcc	select userland programs; names are added to default, while core keeps only core programs
DOCKER_IMAGE	apheleia:latest	image tag	Docker image name

Successful builds write images to:

bin/apheleia_<version>_<arch>.<format>

License

This entire repo is released under the terms of the GPLv3 (see license). Feel free to reuse, build upon or reference this code as long as your projects respect the GPL i.e. are free software themselves.

~ Happy hacking :^)