Welcome to the in progress development of reduceOS.
If you would like to learn more about the development of the kernel, scroll down.
- VESA/VBE graphics drivers
- Filesystem support for EXT2, FAT, and many other UNIX-style device.s
- Support for kernel drivers
- Strong memory manager with liballoc and sbrk support for kernel
- Preemptive multitasking
- ELF file support
- Port of Newlib
YOU WILL NEED A CROSS COMPILER (i686 / x86_64) TO BUILD REDUCEOS
reduceOS requires i686-elf-gcc, make, grub-mkrescue, xorriso
You can emulate reduceOS with qemu-system
Run make targets for a list of targets. To compile reduceOS fully, run make all.
To run reduceOS, you can use the command make qemu.
To use a drive with reduceOS, run make make_drive to create a drive and make qemu_drive to run QEMU with the drive.
You can use the make base target to just build the bare minimum OS.
On build, the kernel and its libc will place their headers in source/sysroot. For the kernel, it will be under sysroot/usr/include/kernel, and for libk it will be under sysroot/usr/include/libk_reduced.
Newlib will place its header files under sysroot/usr/include/. Under no circumstances should this folder be used in modules
PSF files are placed under sysroot/usr/fonts/.
The compiled libk_reduced.a is placed under sysroot/usr/lib, and this path is included in the compiler options for the kernel.
The initial ramdisk and the kernel are placed under sysroot/boot/.
Running qemu make_drive will create an ext2 drive with sysroot as its filesystem.
Scary! I wouldn't do this, but it's possible. Here are some issues I've encountered:
Modules such as the prototype AHCI driver will fail to load. Use the boot argument --skip_modules=<filename> to skip these modules. This should work.
Tasking (last stage) crashes the system The boot argument --no_tasking should help here. Be warned the system will be unstable!
There is no video driver, but I have a COM port! Use the boot argument --headless to put reduceOS into serial-only mode.
If you manage to get reduceOS running, then tell me in our Discord server or in GitHub issues!
reduceOS operates on a semi-modular design, which allows for drivers/modules to be easily made and loaded.
I've written an excellent README for the source/kmods folder, which can be found here - there is also an example module available.
reduceOS will automatically load and handle your modules without needing to modify the parent directory Makefile.
These are going to be moved to GitHub issues.
- Highest priority: New memory subsystem not working with tasking (this is entirely tasking's fault)
- High priority:
vallocsucks - High priority: ATAPI drives cannot be read
- Requires further debugging: Loading bitmaps cause more memory leaks than the Titanic had, and if you try to free buffers they crash.
- TODO: Merge USB driver handling into kernel
- TODO: device/ directory is not present when running
ls - TODO: DMA in IDE/ATA drivers
- Likely will never be fixed: A bitmap that is too large will crash the system
Michael Petch - Patched my terrible interrupts and helped me fix my VMM, even though he didn't have to. Link to this awesome person here
OSDev Wiki - Great resource for anyone looking into OS development. Helped with a ton of the principles and code. Link here
BrokenThorn Entertainment - Incredible tutorials on kernel design, very useful. Link here
ToaruOS - The Misaka kernel and it's modules provide a great example of easy-to-understand, yet robust code. Link here
reduceOS is licensed under the BSD 3-clause license. This license falls under kernel code, kernel modules, libk, polyaniline, and any other source-code elements specific to reduceOS.
For more information on reduceOS licensing, see the LICENSE file.
Other components will usually have a licensing file included, also called LICENSE, in their directories.
If a copyright issue arises, start a GitHub issue or contact me directly for assistance. Thank you!