eduOS - A learning operating system

Introduction

eduOS is a Unix-like computer operating system based on a monolithic architecture for educational purposes. It is derived from following tutorials and software distributions.

1. bkerndev - Bran's Kernel Development Tutorial

   The first steps to realize eduOS based on Bran's Kernel Development Tutorial (http://www.osdever.net/tutorials/view/brans-kernel-development-tutorial). In particular, the initialization of GDT, IDT and the interrupt handlers are derived from this tutorial.

2. kprintf, umoddu3, udivdi3, qdivrem, divdi3, lshrdi3, moddi3, strtol, strtoul, ucmpdi2

   This software contains code derived from material licensed to the University of California by American Telephone and Telegraph Co. or Unix System Laboratories, Inc. and are reproduced herein with the permission of UNIX System Laboratories, Inc.

Requirements of eduOS

• Currently, eduOS supports only x86-based architectures.
• Following command line tools have to be installed: make, gcc, binutil, git, qemu, nams, gdb
• The test PC has to use grub as bootloader.

Building eduOS

1. Copy Makefile.example to Makefile and edit this Makefile to meet your individual convenience.
2. Copy include/eduos/config.h.example to include/eduos/config.h and edit this config file to meet your individual convenience.
3. Build kernel with "make"

Start eduOS via qemu

1. Install qemu to emulate an x86 architecture
2. Start emulator with "make qemu"

Boot eduOS via grub

1. Copy eduos.elf as eduos.bin into the directory /boot. (cp eduos.elf /boot/eduos.bin)
2. Create a boot entry in the grub menu. This depends on the version of grub, which is used by the installed Linux system. For instance, we added following lines to /boot/grub/grub.cfg:

   ### BEGIN /etc/grub.d/40_custom ###
   # This file provides an easy way to add custom menu entries.  Simply type the
   # menu entries you want to add after this comment.  Be careful not to change
   # the 'exec tail' line above.
   menuentry "Boot eduOS!" {
          multiboot       /boot/eduos.bin
          boot
   }

Overview of all branches

1. stage0 - Smallest HelloWorld of the World

   Description of loading a minimal 32bit kernel

2. stage1 - Non-preemptive multitasking

   Introduction into a simple form of multitasking, where no interrupts are required.

Usefull Links

1. http://www.gnu.org/software/grub/manual/multiboot/
2. http://techblog.lankes.org/tutorials/