DOS

A Simple x86 Operating System written in C.

What's working

Grub2

The Kernel is loaded by Grub2. The boot configuration is located in rootfs/boot/grub/grub.cfg.

Multiboot 2

The Kernel is loaded by Grub2 using the Multiboot 2 protocol. The Kernel is loaded at 0x100000 and is loaded in 32-bit mode.

MBR Parsing

The Kernel parses the MBR and finds its own partition. It does not support extended partitions. Then it setups the filesystem and mounts it.

FAT12/16

The Kernel supports FAT12 and FAT16. It can read files and directories. The Kernel cannot write to FAT12/16.

Ext2

The Kernel supports Ext2. It can read files and directories. The Kernel cannot write to Ext2.

Syscalls

The Kernel supports syscalls via the int 0x80 instruction. Currently the following syscalls are supported:

• sys_exit
• sys_write: Only supports stdout
• sys_read: Only supports stdin

ELF parsing

The Kernel can parse ELF files and execute them. It can also load debug symbols from itself.

Kernel Modules

Currently the Kernel is built as a single binary. In the future it will be split into modules. The Kernel will load the modules from the filesystem.

Networking

The Kernel supports the Intel 82540EM series of network cards. It can send and receive packets. The following protocols are supported:

• ARP
• IPv4
• UDP
• TCP
• DHCP
• DNS

Libc

The Kernel is built on top of a primitive libc. It is located in kernel/libc. There's also a system/libc which is used by the userspace programs and in the future will generate a shared library.

Goals

• Grub2
• Multiboot 2
• MBR Parsing
• FAT12/16
• Ext2
• ISO9660
• x86_64
• Syscalls
• Multitasking
• Virtual Memory
• ELF parsing
• Kernel Modules
• ACPI
• ACPICA
• PCI
• ATA
• ATAPI
• Networking
• Virtual File System
• Init System
• Shell
• Libc