LF OS

This is the 5th(?) attempt at writing an operating system from scratch, where "attempt" means: starting from zero.

Development mainly happens on my Gitlab at https://praios.lf-net.org/littlefox/lf-os_amd64 - check it out!

It can run Doom!

Key difference to previous attempts

• amd64, why use i386 like everyone else when I did not even manage to get a working system there?
• uefi and custom loader, why use Grub like everyone else when I did not even ...... ^
• I'm actually able to program things now
  • I actually became a good software developer in the meantime
  • first attempt was even before finishing school
• there are some docs
• I thought about system design and even wrote some things down
• I don't write throw-away code or just paste tutorials right now
  • maybe later in user space though

Design

This will be a microkernel providing the following inside the kernel

• base system initialization (CPU, physical memory, common bus systems)
• memory management for processes (virtual memory)
• inter-process communication facilities
  • mostly via shared memory and message queues
  • later also via helper userspace programs to make communication between processes A and B over an arbitrary channel between C and D, where A, B, C and D may run on different computers
  • IPC between different computers will be transparent to processes in a later version
• service registry
  • processes announce services (file system, block device, character device, ...)
  • other processes need services
  • ask kernel for process implementing service x
  • IPC to process for service x

All drivers for special hardware (everything not attached to a common bus) are userspace programs that will be designed to recover after crashed. They can store a small amount of information in the kernel (like hard disk x is fully initialized, just read from address $y and port $x) and when they crash, they are just restarted.

Since IPC between processes running on different computers is planned to be transparent, it's actually possible to run a single instance of LF OS on a whole data center (or bigger, but latency).