Welcome to the in progress development of reduceOS.
If you would like to learn more about the development of the kernel, scroll down.
reduceOS has switched to a brand new kernel, with cleaner, commented code and more features. This kernel is also written entirely by me, without a base.
To build reduceOS, you need these packages: i686-elf-gcc, nasm, make, grub
To run reduceOS, you need these packages: qemu-system (emulation), grub2-common, and xorriso
BEFORE ANYTHING, run make clean. I may or may not leave build files built on my machine, and if so I apologize (really bad habit) but to prevent anything always CLEAN
There are two targets available to build reduceOS for - RELEASE and DEBUG.
To change the target you want to build, edit the make.config file to have BUILD_TARGET set to either release or debug.
Then, you can run make build iso to build an ISO in out/iso.
Run make targets to get a full list of targets.
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:
reduceOS will commonly fail to initialize a video driver. If this happens you'll see the message that says "BIOS call failed". To fix this, add --force_vga to the boot arguments in GRUB (the only way you'll see the BIOS call failed message is with this anyways)
- IMPORTANT: The kernel's bootloader will automatically ask GRUB for a framebuffer in 1024x768x32 mode. If GRUB provides this, it will set the mode and render it useless.
Occasionally module and debug symbols will fail to load. No way to fix this unless you patch the kernel.
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.
- Highest priority: Exiting tasks after forking will crash.
- High priority: ATAPI drives cannot be read
- High priority: Being in a higher resolution while running tasks will crash the system due to an invalid heap relocation
- Requires further debugging: Loading bitmaps cause more memory leaks than the Titanic had, and if you try to free buffers they crash.
- Medium priority: Memory dumping will crash and corrupt the drive.
- TODO: Merge USB driver handling into kernel
- TODO: device/ directory is not present when running
ls - TODO: DMA in IDE/ATA driver
- TODO: System calls need a better interface(?)
- TODO: ext2 driver deletion functions suck
- Likely will never be fixed: Kernel security is not being upheld with usermode as kernel pages are RW. Not good! (needs to be fixed in allocatePage)
- 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
If I used your code in your repo without properly crediting it, please create a GitHub issue and I will resolve it right away!