piOS

Operating system for my custom processor - pcpu

This is my self-educational project. Homemade OS created because I wanted to make something fun for my processor, and got interested in operating systems.

You can get tools to build and emulate it from here: pcpu-toolchain

In development, don't expect too much from it yet.

Features

• Runs on 16 bit pcpu
• VGA driver
• PS/2 Keyboard
• First userspace process which can be interrupted and resumed
• Kernel library: printf, malloc, strings, data structures, logs
• SD card driver over SPI bus
• TAR filesystem support

Not much yet, but the os is in early development stage now. I will keep the list this updated.

Runing processes in userspace is supported, so this is a real OS now!

Note that all devices are specific to my dev board.

Incoming features

• Kernel threads
• Kernel synchronization primitives
• Main syscall queue and dispatcher
• System design documentation

Build

Build piOS kernel

cd kernel
# build .hex
make
# or build and upload to dev board
make upload
# or build and run in emulator
make pce

If using pce add test.tar archive in main directory for sd card emulation.

OS goals

• Multiprocessing and networking - run simple web server in background
• UNIX-like shell
• Virtual file system with UNIX-like devices
• Virtual memory managment
• Custom user process managment, without kernel thread for each process

Author

piOS (C) 2021-2022 by Piotr Wegrzyn