klange's OS Development Repo

I'm writing an OS because I'm bored and want a massive project to suck up the little pieces of my time for the next few years.

Testing it Out

Grab bootdisk.img from the git repo and load it into a virtual machine. The bootdisk will start GRUB with a single menu entry to boot the kernel off of the same diskette.

For example, you can boot the disk in qemu:

qemu -fda bootdisk.img

Or you could set up a VirtualBox machine and load the floppy image.

Goals and Roadmap

Overall, the goal of this project is to write a relatively POSIX-compatible OS from the ground up. With a focus on generic hardware functionality and universal specifications like VESA, I hope to eventually get something fairly complete in terms of what an OS should be. At some times, I may focus on an actual piece of complex hardware (I am looking to write a basic driver for Intel graphics cards based on the X driver and the Mesa components), but in general, I will stick to generic interfaces.

Basic Goals

• Create a working modular monolithic kernel capable of executing arbitrary ELF binaries
• Write, from scratch, a C standard library using past experience in writing standard library functions
• Support POSIX threads
• Implement an existing file system, specifically EXT2
• Be able to manipulate VESA modes to run at an optimal resolution for graphics
• Handle basic networking on a virtual Ethernet device (DHCP, TCP, etc.)

Loftier Goals

Some things are far easier said than done, but I like to say them anyway. The time span for these depends greatly on how quickly the basic goals are completed and can range anywhere from a few months to years from now.

• Create a working implementation of Wayland under VESA (will be slow)
• Port Qt (under Wayland) and some Qt apps
• Support audio in a way that doesn't suck like Linux's mess of libraries and mixers
• Various hardware-specific drivers (primarily for my T410):
  • Intel graphics driver, with acceleration so Wayland isn't slow
  • Realtek wireless driver, with WPA2
  • Specific drivers for the Thinkpad itself (or just acpi?)

Roadmap

Currently, I have a kernel capable of reading its multiboot parameters, which is terribly un-useful. The current, ordered, plan of attack is as follows:

• Finish James M's tutorial (second half), which covers:
  • Paging
  • Heap
  • VFS
  • Initial RAM Disk (except I'll probably use my own format for the directory structure)
  • Multitasking
  • User mode
• Finish basic kernel functionality
  • Loading ELF binaries and executing them in user mode
  • Complete system call table
  • Get a better semblance of users and groups
• Write a file system driver for a real file system
  • Target is EXT2, but might do FAT
  • Move OS development images to some form of virtual drive (VDI or something QEMU compatible)
• Implement a VESA mode handler
  • Requires a Virtual 8086 monitor
  • Need to be able to use graphics modes and still have output, so write a framebuffer terminal
• Complete libc
  • Enough to run basic unix tools...
• Port some basic UNIX tools
  • a shell (bash and zsh, because I like bash, but the office uses zsh)
  • ls, mv, rm, etc.
  • here's a real test: perl
• Implement networking
  • IPv4
  • Ethernet driver for QEMU or VirtualBox

Anything beyond this point is part of the 'Loftier Goals' section

• Wayland compositor
  • based on specifications for a Wayland environment
  • Port some of the Wayland sample applications
  • Write my own!
• Port Qt
  • Specifically, for Wayland
  • Qt is huge and has its own standard library, might need more extensive libc
  • Need to support C++-built stuff, so will probably need a C++ stdlib.
• Audio drivers
  • Maybe before Qt?
  • Should support software mixing at least, hardware under a virtual machine, maybe my Intel hw

References

I'll be more detailed here eventually, but for the most part, I have been using:

• James M's kernel development tutorials
• [Bran's Kernel Development Tutorial}(http://www.osdever.net/bkerndev/) completed
• Skelix's OS tutorial