A tiny set of libraries and a tiny bootloader for creating bare-metal programs for 32-bit x86
"Metalkit" is what I'm calling this set of software modules for assembling simple programs that operate on the bare metal: they run on IA32 PCs without any operating system.
This software is released under the MIT license, so you're free to copy, modify, and distribute it for commercial or noncommercial purposes.
Learning about PC architecture or systems programming.
For hardware (or virtual machine) developers, writing test cases or example programs that demonstrate hardware features.
Simple applications (even games) that can target common virtual machines or emulators (QEMU, VMware, Bochs) as their platform.
It has a nifty bootloader which can bootstrap a 32-bit protected mode program from either a raw floppy disk image (convenient for Virtual Machines), from GRUB (convenient for real PCs), or from a USB thumb drive (supports very large binary images).
When running from a USB disk on a BIOS that supports LBA mode, it can load very large binary images. I tested loading a 128MB image on my IBM Thinkpad.
It has simple PCI bus support. So far it's enough to enumerate the attached devices.
VGA text mode, with a simple Console abstraction.
Fault handlers, and a "red screen of death" for Panic and Unhandled Fault errors.
Support for 16-bit BIOS calls (switching back to real mode temporarily, then back to protected mode)
VESA BIOS graphics.
Interrupt handlers, very simple thread switching.
It has a simple PS/2 keyboard driver.
It supports basic PIT timer configuration.
Tested on VMware, Bochs, and a real PC.
It's easy. On any x86 system with a 32-bit GNU toolchain installed, enter an example directory and type 'make'. You should end up with a '.img' file. You can either:
Reboot your PC, and use grub to boot this file as a 'kernel'.
Point your virtual machine or emulator of choice to boot.img as a floppy disk image.
Use 'dd' to copy the image to a USB disk, then use your BIOS boot menu to select the USB disk. Make sure to copy the image to the entire disk, not a single partition (like /dev/sdX, not /dev/sdX1).
Higher-level libraries for threading.
An optional standard C library (probably newlib), for apps that need one.
Higher-level interfaces for video
A simple single-tasking event driven runloop.
Video, mouse, and keyboard drivers. (For generic PC hardware, and for VMware's mouse and video devices.)