Hey everyone. Didn't expect to see this here. I made this for my operating systems class a few years ago. Unfortunately I can't share the code because the rest of the OS is used as assignments for the class, but it was a fun project.

It's not highlighted much in the writeup, but most of the interaction takes place in the terminal. The original assignments just use text mode. The graphics mode got started when I tried to implement ANSI escape codes in the terminal, but some of the effects weren't possible in text mode. I changed the bootloader to switch the system into a known graphics mode, then implemented a terminal emulator on top of that. From there it was just a small matter of mouse drivers and windowing commands.

JOS is a unix-inspired exokernel. It has virtual memory with thread isolation, a pre-emptive scheduler (round-robin, I think), and IPC. Everything else lives in user-land. As alluded to, the disk drivers even run in a user-land process which has been given access to the disk IO port. My windowing system is also a user-land process, which leases out buffers of memory as windows and has been given access to the memory-mapped screen buffer.